| 1. |
- Axelsson, Karl-Jonas, et al.
(författare)
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Adaptation of ventricular repolarization dispersion during heart rate increase in humans: A roller coaster process.
- 2021
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Ingår i: Journal of electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 68, s. 90-100
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Tidskriftsartikel (refereegranskat)abstract
- Regional differences in ventricular activation sequence and action potential duration and morphology result in dispersion in ventricular repolarization (VR). VR dispersion is a key factor in arrhythmogenesis. We studied the adaptation of global VR dispersion in humans during normal and abnormal ventricular activation, and the relation to the QT adaptation (hysteresis).We measured global VR dispersion as T amplitude, T area, and ventricular gradient (VG), using continuous Frank vectorcardiography, in response to abrupt and sustained atrial (AP) or ventricular pacing (VP) aiming at 120 bpm, in 21 subjects with permanent pacemakers.Following pacing start, VR adaptation showed an initially rapid and complex tri-phasic pattern, most pronounced for T amplitude. There were major differences in the patterns of VR dispersion adaptation following abrupt AP vs VP, confirming that the adaptation pattern is activation dependent. In response to AP, an instantaneous decrease in VR dispersion occurred, followed by an increase and then a slow decrease, all at a lower level than baseline. In contrast, following VP there was an immediate increase to ~4× baseline in T amplitude and T area (but not in VG), with a subsequent biphasic adaptation lasting longer during VP than AP. The initial rapid changes occurred within the time for QT adaptation to reach steady-state.Our results corroborate and expand data from animal and invasive human studies, showing similarities of the adaptation pattern on different scales. The initial rapidly changing VR adaptation phase presumably reflects a window of increased vulnerability to arrhythmias.
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| 2. |
- Axelsson, Karl-Jonas, et al.
(författare)
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Adaptation of ventricular repolarization duration and dispersion during changes in heart rate induced by atrial stimulation.
- 2020
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Ingår i: Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc. - : Wiley. - 1542-474X. ; 25:3
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Tidskriftsartikel (refereegranskat)abstract
- The duration of ventricular repolarization (VR) and its spatial and temporal heterogeneity are central elements in arrhythmogenesis. We studied the adaptation of VR duration and dispersion and their relationship in healthy human subjects during atrial pacing.Patients 20-50 years of age who were scheduled for ablation of supraventricular tachycardia without preexcitation but otherwise healthy were eligible. Vectorcardiography recordings with Frank leads were used for data collection. Incremental atrial pacing from a coronary sinus electrode was performed by decrements of 10ms/cycle from just above sinus rate, and then kept at a fixed heart rate (HR) just below the Wenckebach rate for ≥5min and then stopped. VR duration was measured as QT and VR dispersion as T area, T amplitude and ventricular gradient. The primary measure (T90 End) was the time to reach 90% change from baseline to the steady state value during and after pacing.A complete study protocol was accomplished in 9 individuals (6 women). VR duration displayed a monophasic adaptation during HR acceleration lasting on average 20s. The median (Q1-Q3) T90 End for QT was 85s (51-104), a delay by a factor >4. All dispersion measures displayed a tri-phasic response pattern during HR acceleration and T90 End was 3-5 times shorter than for VR duration.Even during close to "physiological" conditions, complex and differing response patterns in VR duration and dispersion measures followed changes in HR. Extended knowledge about these responses in disease conditions might assist in risk evaluation and finding therapeutic alternatives.
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| 3. |
- Axelsson, Karl-Jonas, et al.
(författare)
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Adaptation of ventricular repolarization time following abrupt changes in heart rate: comparisons and reproducibility of repeated atrial and ventricular pacing.
- 2021
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Ingår i: American journal of physiology. Heart and circulatory physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 320:1
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Tidskriftsartikel (refereegranskat)abstract
- Adequate adaptation of ventricular repolarization (VR) duration to changes in heart rate (HR) is important for cardiac electromechanical function and electrical stability. We studied the QT and QTpeak adaptation in response to abrupt start and stop of atrial and ventricular pacing on two occasions with an interval of at least 1 mo in 25 study subjects with permanent pacemakers. Frank vectorcardiography was used for data collection. Atrial or ventricular pacing was performed for 8min aiming at a cycle length (CL) of 500ms. We measured the immediate response (IR), the time constant (τ) of the exponential phase, and T90 End, the time to reach 90% change of QT and QTpeak from baseline to steady state during and after pacing. During atrial pacing, the CL decreased on average 45% from mean (SD) 944 (120) to 518 (46) ms and QT decreased on average 18% from 388 (20) to 318 (17) ms. For QT, T90 End was 103 (24) s and 126 (15) s after start versus stop of atrial pacing; a difference of 24 (27) s (P = 0.006). The response pattern was similar for τ but IR did not differ significantly between pacing start and stop. The response pattern was similar for QTpeak and also for QT and QTpeak following ventricular pacing start and stop. The coefficients of variation for repeated measures were 7%-21% for T90 End and τ. In conclusion, the adaptation of VR duration was significantly more rapid following increasing than decreasing HR and intraindividually a relatively reproducible process.NEW & NOTEWORTHY We studied the duration of ventricular repolarization (VR) adaptation and its hysteresis, following increasing and decreasing heart rate by abrupt start and stop of 8-min atrial or ventricular pacing in study subjects with permanent pacemakers and repeated the protocol with ≥1 mo interval, a novel approach. VR adaptation was significantly longer following decreasing than increasing heart rate corroborating previous observations. Furthermore, VR adaptation was intraindividually a reproducible and, hence, robust phenomenon, a novel finding.
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| 4. |
- Bengtsson, Karin, et al.
(författare)
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Cardiac conduction disturbances in patients with ankylosing spondylitis : results from a 5-year follow-up cohort study
- 2019
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Ingår i: RMD Open. - : BMJ Publishing Group Ltd. - 2056-5933. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To describe electrocardiographic (ECG) development in patients with ankylosing spondylitis (AS) and identify associations between baseline characteristics and cardiac conduction disturbances (CCD) at 5-year follow-up.Methods: In a longitudinal cohort study, 172 patients (54% men, mean age (SD) of 50 (13) years at baseline) with AS underwent ECG, physical examination, questionnaires and laboratory testing at baseline and at 5-year follow-up. Descriptive statistics and univariate and age- and sex-adjusted logistic regression analyses were used. CCD included both atrioventricular and intraventricular blocks.Results: Twenty-three of the 172 patients (13.4%) had a CCD at follow-up. Eight patients had developed a new CCD and eight had normalised their ECG. In the age- and sex-adjusted analyses, CCD at baseline (OR 24.8, 95% CI 7.3 to 84.5), male sex (OR 6.4, 95% CI 2.0 to 20.8), history of anterior uveitis (OR 4.4, 95% CI 1.3 to 14.5), higher ASDAS-CRP (OR 2.3, 95% CI 1.3 to 4.0), greater waist circumference (OR 1.3, 95% CI 1.1 to 1.6, per 5 cm), and medication with antiplatelets (OR 7.0, 95% CI 1.5 to 31.8) and beta-blockers (OR 3.4, 95% CI 1.0 to 11.5) were associated with a CCD at follow-up. Higher age and longer symptom duration were highly correlated and were both associated with a CCD at follow-up.Conclusions: The presence of CCD in AS is in part dynamic and associated with both AS and non-AS characteristics. Our results suggest that patients especially prone to present with CCDs are older men with a previous CCD, longer symptom duration, higher AS disease activity, a history of anterior uveitis and medication reflecting cardiovascular disease.
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| 5. |
- Bergfeldt, Lennart, 1950, et al.
(författare)
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Non-invasive electrophysiological differences between women and men:differences in body size not an explanation.
- 2022
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Ingår i: American journal of physiology. Heart and circulatory physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 323:5
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Tidskriftsartikel (refereegranskat)abstract
- There are numerous sex-related differences in cardiac electrophysiology and arrhythmia propensity but very little knowledge about the reasons. Difference in body size has been proposed as one reason and was tested in this study of >20 cardiac electrophysiology parameters in 319 (158 women) apparently healthy 50-64 years old subjects from a randomly enrolled population sample, the SCAPIS pilot study (Swedish CArdio-Pulmonary bioImaging Study), using Frank vectorcardiography. We studied conventional conduction intervals, parameters reflecting electrical heterogeneity (dispersion) in the ventricles, QRS- and T-vector directions, spatial QRS-T angles, and T-vector loop morphology. Body surface area (BSA; two methods) and lean body mass (LBM), both estimated from body weight and height, were used as body size parameters. According to multivariable linear regression analysis adjusted for sex, there was no association between electrophysiological parameters and body size apart from QRS duration and QRSarea. In conclusion, most electrophysiological parameters assessed completely non-invasively and showing statistically significant differences between women and men on the group level show no association with BSA or LBM. Scaling (indexing) the electrophysiological parameters for body size parameters are therefore not an option. As a consequence, the explanation for the sex-related electrophysiological differences should be sought along other lines.
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| 6. |
- Bergfeldt, Lennart, 1950, et al.
(författare)
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Spatial peak and mean QRS-T angles: A comparison of similar but different emerging risk factors for cardiac death.
- 2020
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Ingår i: Journal of electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 61, s. 112-120
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Tidskriftsartikel (refereegranskat)abstract
- The spatial peak and mean QRS-T angles are scientifically but not clinically established risk factors for cardiovascular events including cardiac death. The study aims were to compare these angles, assess their association with hypertension (HT) and diabetes mellitus (DM), and explore the relation between the mean QRS-T angle and the ventricular gradient (VG; reflecting electrical heterogeneity), which both are derived from the QRSarea and Tarea vectors.Altogether 1094 participants (aged 50-65years, 550 women) from the pilot of the population-based Swedish CArdioPulmonary bioImage Study with Frank vectorcardiographic recordings were included and divided into 5 subgroups: apparently healthy n=320; HT n=311; DM n=33; DM+HT n=53; miscellaneous conditions n=377. Abnormal peak and mean QRS-T angles were defined as >95th percentile.Peak QRS-T angles were generally narrower than the mean QRS-T angles; both were narrower in women than in men. Abnormal peak (>124°) and/or mean (>119°) QRS-T angles were found in 73 participants (6.7%). The concordance regarding abnormal versus normal-borderline QRS-T angles was good (Cohen's kappa 0.61). The prevalence of abnormal angles varied from 2.5% in healthy to 21.2% in DM. There was an inverse logarithmical relation between the mean QRS-T angle and the VG.The peak and mean QRS-T angles are not interchangeable but complementary. DM, HT, sex and absence of disease are important determinants of both QRS-T angles. The mean QRS-T angle and the VG relationship is complex. All three VCG derived measures reflect related but differing electrophysiological properties and have potential prognostic value vis-à-vis cardiovascular events.
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| 7. |
- Bergfeldt, Lennart, 1950, et al.
(författare)
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Ventricular repolarization duration and dispersion adaptation after atropine induced rapid heart rate increase in healthy adults.
- 2017
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Ingår i: Journal of electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 50:4, s. 424-432
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Tidskriftsartikel (refereegranskat)abstract
- Proper adaptation of ventricular repolarization (VR) to rapid heart rate (HR) increase is crucial for cardiac electro-mechanical function. The pattern and temporal aspects of this adaptation and its components (duration and dispersion) during normal conduction are, however, incompletely known in humans and were the topic of this study.The VR duration (QT & QTpeak) and dispersion (Tamplitude, Tarea & ventricular gradient; VG) responses were studied by continuous vectorcardiogram after a bolus injection of atropine 0.04mg/kg b.w. in 31 healthy young adults (16 men). The primary measure (T90 End) was the time to reach 90% change from baseline to end value 300s later. Mean (SD) of T90 End was 23 (9) s for a 41% RR decrease, 130 (35) s for a 16% QTend decrease and 110 (36) s for a 19% QTpeak decrease; the response was single-exponential for these measures. For 35-43% decreases of Tamplitude, Tarea & VG, mean (SD) of T90 End were 21 (10), 38 (20) and 40 (23) s and the response pattern was double-exponential with varying overshoot.VR duration and dispersion responses to a very rapid HR increase during normal conduction differed substantially. In contrast to the well-known single-exponential delay in VR duration adaptation the responses of VR dispersion measures were double-exponential and much more rapid. We describe a new and completely non-invasive phenotypic characterization of different components of VR adaptation.
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| 8. |
- Bergfeldt, Ulla, et al.
(författare)
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Cortical activation changes and improved motor function in stroke patients after focal spasticity therapy- an interventional study applying repeated fMRI.
- 2015
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Ingår i: BMC neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Impaired dominant hand function in stroke patients is a common clinical problem. Functional improvement after focal spasticity therapy is well documented but knowledge about central correlates is sparse. Brain activity was therefore followed during therapy with repeated functional magnetic resonance imaging (fMRI). The purpose was to analyse motor function and central nervous system (CNS) correlates in response to a standardized motor task in stroke patients after a comprehensive focal spasticity therapy.
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| 9. |
- Dahlberg, Pia, et al.
(författare)
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Accelerated QT adaptation following atropine-induced heart rate increase in LQT1 patients versus healthy controls: A sign of disturbed hysteresis.
- 2022
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Ingår i: Physiological reports. - : Wiley. - 2051-817X. ; 10:21
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Tidskriftsartikel (refereegranskat)abstract
- Hysteresis, a ubiquitous regulatory phenomenon, is a salient feature of the adaptation of ventricular repolarization duration to heart rate (HR) change. We therefore compared the QT interval adaptation to rapid HR increase in patients with the long QT syndrome type 1 (LQT1) versus healthy controls because LQT1 is caused by loss-of-function mutations affecting the repolarizing potassium channel current IKs , presumably an important player in QT hysteresis. The study was performed in an outpatient hospital setting. HR was increased in LQT1 patients and controls by administering an intravenous bolus of atropine (0.04mg/kg body weight) for 30s. RR and QT intervals were recorded by continuous Frank vectorcardiography. Atropine induced transient expected side effects but no adverse arrhythmias. There was no difference in HR response (RR intervals) to atropine between the groups. Although atropine-induced ΔQT was 48% greater in 18 LQT1 patients than in 28 controls (p<0.001), QT adaptation was on average 25% faster in LQT1 patients (measured as the time constant τ for the mono-exponential function and the time for 90% of ΔQT; p<0.01); however, there was some overlap between the groups, possibly a beta-blocker effect. The shorter QT adaptation time to atropine-induced HR increase in LQT1 patients on the group level corroborates the importance of IKs in QT adaptation hysteresis in humans and shows that LQT1 patients have a disturbed ultra-rapid cardiac memory. On the individual level, the QT adaptation time possibly reflects the effect-size of the loss-of-function mutation, but its clinical implications need to be shown.
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| 10. |
- Dahlberg, Pia, et al.
(författare)
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Spatio-temporal repolarization dispersion before and after exercise in patients with long QT syndrome type 1 vs controls - probing into the arrhythmia substrate.
- 2023
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Ingår i: American journal of physiology. Heart and circulatory physiology. - 1522-1539. ; 325:6
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Tidskriftsartikel (refereegranskat)abstract
- Congenital long QT syndrome (LQTS) carries an increased risk for syncope and sudden death. QT prolongation promotes ventricular extrasystoles which in the presence of an arrhythmia substrate might trigger ventricular tachycardia degenerating into fibrillation. Increased electrical heterogeneity (dispersion) is the suggested arrhythmia substrate in LQTS. In the most common subtype LQT1, physical exercise predisposes for arrhythmia and spatio-temporal dispersion was therefore studied in this context. Thirty-seven patients (57% on beta-blockers) and 37 healthy controls (mean age 31 vs 35, range 6-68 vs 6-72 years) performed an exercise test. Frank vectorcardiography was used to assess spatio-temporal dispersion as Tamplitude, Tarea, the ventricular gradient (VG), and the Tpeak-end interval from 10s-signal averages before and 7±2 min after exercise; during exercise too much signal disturbance excluded analysis. Baseline and maximum heart rates as well as estimated exercise intensity were similar, but heart rate recovery was slower in patients. At baseline QT and heart rate corrected QT (QTcB) were significantly longer in patients (as expected), while dispersion parameters were numerically larger in controls. After exercise QTpeakcB and Tpeak-endcB increased significantly more in patients (18±23 vs 7±10ms and 12±17 vs 2±6ms; p<0.001 and p<0.01). There was, however, no difference in the change in Tamplitude,Tarea and VG between groups. In conclusion, while temporal dispersion of repolarization increased significantly more after exercise in LQT1 patients, there were no signs of exercise-induced increase in global dispersion of action potential duration and morphology. The arrhythmia substrate/mechanism in LQT1 warrants further study.
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| 11. |
- Lundahl, Gunilla, et al.
(författare)
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Automatic identification of a stable QRST complex for non-invasive evaluation of human cardiac electrophysiology.
- 2020
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 15:9
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Tidskriftsartikel (refereegranskat)abstract
- A vectorcardiography approach to electrocardiology contributes to the non-invasive assessment of electrical heterogeneity in the ventricles of the heart and to risk stratification for cardiac events including sudden cardiac death. The aim of this study was to develop an automatic method that identifies a representative QRST complex (QRSonset to Tend) from a Frank vectorcardiogram (VCG). This method should provide reliable measurements of morphological VCG parameters and signal when such measurements required manual scrutiny.Frank VCG was recorded in a population-based sample of 1094 participants (550 women) 50-65 years old as part of the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot. Standardized supine rest allowing heart rate stabilization and adaptation of ventricular repolarization preceded a recording period lasting ≥5 minutes. In the Frank VCG a recording segment during steady-state conditions and with good signal quality was selected based on QRST variability. In this segment a representative signal-averaged QRST complex from cardiac cycles during 10s was selected. Twenty-eight morphological parameters were calculated including both conventional conduction intervals and VCG-derived parameters. The reliability and reproducibility of these parameters were evaluated when using completely automatic and automatic but manually edited annotation points.In 1080 participants (98.7%) our automatic method reliably selected a representative QRST complex where its instability measure effectively identified signal variability due to both external disturbances ("noise") and physiologic and pathophysiologic variability, such as e.g. sinus arrhythmia and atrial fibrillation. There were significant sex-related differences in 24 of 28 VCG parameters. Some VCG parameters were insensitive to the instability value, while others were moderately sensitive.We developed an automatic process for identification of a signal-averaged QRST complex suitable for morphologic measurements which worked reliably in 99% of participants. This process is applicable for all non-invasive analyses of cardiac electrophysiology including risk stratification for cardiac death based on such measurements.
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| 12. |
- Vahedi, Farzad, et al.
(författare)
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Instability of repolarization in LQTS mutation carriers compared to healthy control subjects assessed by vectorcardiography
- 2013
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Ingår i: Heart Rhythm. - : Elsevier BV. - 1547-5271 .- 1556-3871. ; 10:8, s. 1169-1175
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Potassium channel dysfunction in congenital and acquired forms of long QT syndrome types 1 and 2 (LQT1 and LQT2) increases the beat-to-beat variability of the (IT interval. OBJECTIVE To study about the little known variability (instability) of other aspects of ventricular repolarization (VR) in humans by using vectorcardiography. METHODS Beat-to-beat analysis was performed regarding vectorcardiography derived RR, QRS, and QT intervals, as well as T vector- and T vector loop-based parameters during 1-minute recordings of uninterrupted sinus rhythm at rest in 41 adult LQT1 (n = 31) and LQT2 (n = 10) mutation carriers and 41 age- and sex-matched control subjects. The short-term variability for each parameter, describing the mean orthogonal distance to the line of identity on the Poincare plot, was calculated. RESULTS Mutation carriers showed significantly larger (by a factor 2) instability in most VR parameters compared to controls despite higher instantaneous heart rate variability (STVRR) in the control group. The longer the (IT interval, the greater was its instability, and the instability of VR dispersion measures. CONCLUSIONS A greater instability of most aspects of VR already at rest seems to be a salient feature in both LQT1 and LQT2, which might pave the way for early afterdepolarizations and torsades de pointes ventricular tachycardia. In contrast, no signs of increased VR dispersion per se were observed in mutation carriers.
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| 13. |
- Aagaard, Per, 1957, et al.
(författare)
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Early repolarization in ECG. Definition, prevalence and prognostic significance
- 2015
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Ingår i: Läkartidningen. - 0023-7205. ; 112
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Tidskriftsartikel (refereegranskat)abstract
- Early repolarization defined as antero-lateral ST-segment elevation exists in 1-2 % of the general population and has been considered a benign ECG finding for decades. However, early repolarization, defined as infero-lateral J-waves, has in recent studies been associated with an increased - albeit low - risk of sudden and cardiovascular death. This ECG pattern is present in 3-13% of the general population. However, exercise training can induce all types of early repolarization, and the prevalence in the athletic population rises to 20-90%. There is large variability between sports (higher in endurance athletes) and also throughout the season (higher during times of peak fitness). In athletes, early repolarization, regardless of type, is considered benign. In asymptomatic non-athletes, the absolute risk is too low to use this ECG finding in clinical practice. In individuals with J-wave syndrome, on the other hand, ICD implantation should be strongly considered to prevent sudden cardiac death.
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| 14. |
- Aagaard, Philip, et al.
(författare)
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Early Repolarization in Middle-Age Runners-Cardiovascular Characteristics.
- 2014
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 46:7, s. 1285-1292
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: This study aimed to assess the prevalence and patterns of early repolarization (ER) in middle-age long-distance runners, its relation to cardiac structure and function, and its response to strenuous physical activity. Methods: Male first-time cross-country race participants >45 yr were assessed pre-and postrace by medical history and physical examination, 12-lead ECG, vectorcardiography, blood tests, and echocardiography. ER was defined either as ST elevation or J wave and categorized according to localization and morphology. Results: One hundred and fifty-one subjects (50 +/- 5 yr) were evaluated before the race, and 47 subjects were evaluated after the race. Altogether, 67 subjects (44%) had ER. Subjects with versus without ER had a lower resting HR (56 +/- 8 vs 69 +/- 9 bpm, P = 0.02), lower body mass index (24 +/- 2 vs 25 +/- 3 kg.m(-2), P < 0.001), higher training volume (3.0 +/- 2.6 vs 2.1 +/- 2.7 h.wk(-1), P = 0.03), and faster 30-km running times (194 +/- 28 vs 208 +/- 31 min, P = 0.01). Vectorcardiography parameters in subjects with ER showed more repolarization heterogeneity: vector gradient (QRS-T-area) (120 +/- 25 vs 92 +/- 29 mu Vs, P < 0.001), T-area (105 +/- 18 vs 73 +/- 23 mu Vs, P < 0.001), and T-amplitude (0.63 +/- 0.13 vs 0.53 +/- 0.16 mm, P < 0.001); these parameters were inversely related to HR (r = -0.37 to -0.48, P < 0.001). ER disappeared in 15 (75%) of 20 subjects after the race. Conclusions: ER is a common finding in middle-age male runners. This ECG pattern, regardless of morphology and localization, is associated with normal cardiac examinations including noninvasive electrophysiology, features of better physical conditioning, and disappears after strenuous exercise in most cases. These findings support that ER should be regarded as a common and training-related finding also in middle-age physically active men.
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| 15. |
- Aagaard, Per, 1957, et al.
(författare)
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Heart Rate and Its Variability in Response to Running-Associations with Troponin
- 2014
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Ingår i: Medicine and Science in Sports and Exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131. ; 46:8, s. 1624-1630
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The objective of this study is to investigate the time course of autonomic tone changes after a first-time endurance running race participation and associations with postexertional high-sensitivity troponin (hsTnT) levels in middle-aged males. Methods: Male (n = 42) first-time long-distance running race (Lidingoloppet 30 km) participants >= 45 yr (50.5 +/- 5) were examined. HR and HR variability (HRV) in the time domain (SDANN) was measured continuously from 2 d before to 4 d after the race using a wireless cardiovascular monitor that also recorded arrhythmia episodes. In addition, subjects were assessed pre- and postrace by medical history and physical examination, 12-lead ECG, blood tests including hsTnT, and echocardiography. Results: Compared with corresponding prerace values, nighttime (2: 00-4: 00 a.m.) HR was significantly elevated (63.6 +/- 9.4 vs 53.9 +/- 8.3 bpm, P < 0.001) on the first night postrace, whereas HRV remained reduced for a median of 64 h (interquartile range, 51-102 h). A prolonged HR recovery period (r = 0.48, P = 0.005) and a larger reduction in postrace HRV (r = -0.49, P = 0.003) correlated with higher postrace hsTnT levels. The association between reduced HRV and higher hsTnT remained significant after multivariate analysis (A = -0.48, P = 0.01). No sustained ventricular arrhythmias were recorded, but atrial fibrillation occurred in two subjects. Conclusion: Endurance running race participation caused a prolonged alteration of autonomic tone. More marked and prolonged changes were associated with higher levels of hsTnT, suggesting that the magnitude of troponin increase after strenuous exercise may reflect the magnitude of exercise-induced cardiovascular stress.
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| 16. |
- Aagaard, Per, 1957, et al.
(författare)
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Preparticipation Evaluation of Novice, Middle-Age Long-Distance Runners.
- 2013
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Ingår i: Medicine and science in sports and exercise. - 0195-9131 .- 1530-0315. ; 45:1, s. 130-137
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Tidskriftsartikel (refereegranskat)abstract
- Abstract PURPOSE: To assess the cardiovascular health and risk profile in middle-aged males making an entry to participate for their first time in a long-distance race. METHODS: Male first-time participants ≥45 years in the world's largest cross-country running race, the Lidingöloppet, were evaluated with a medical history and physical exam, European risk-SCORE, 12-lead ECG, echocardiography and blood tests. Further diagnostic work-up was performed when clinically indicated. RESULTS: Of 265 eligible runners, 153 (58%, age 51±5 y) completed the study. While the 10-year fatal cardiovascular event risk was low (SCORE: 1% (IQR: 0 - 1%)), mild abnormalities were common, e.g. elevated blood-pressure (19%), left ventricular hypertrophy (6%), elevated LDL cholesterol (5%). ECG changes compatible with "athlete's heart" were present in 82%, e.g. sinus bradycardia (61%) and/or early repolarization (32%). ECG changes considered training-unrelated were found in 24%, e.g. prolonged QTc: 13%; left axis deviation: 5.3%; left atrial enlargement: 4%). In 14 runners (9%) additional diagnostic work-up was clinically motivated, and 4 (2%) were ultimately discouraged from vigorous exercise due to QTc intervals >500 ms (n=2), symptomatic atrioventricular block (n=1), and a cardiac tumor (n=1). The physician exam and the ECG identified 12 of the 14 subjects requiring further evaluation. CONCLUSIONS: Cardiovascular evaluation of middle-aged men, including a physician exam and a 12-lead ECG, appears useful to identify individuals requiring further testing prior to vigorous exercise. The additional yield of routine echocardiography was small.
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| 17. |
- Aagaard, Philip, et al.
(författare)
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Tidig repolarisation på EKG - Definitioner, prevalens och prognostisk betydelse.
- 2015
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Ingår i: Läkartidningen. - 1652-7518. ; 112
-
Tidskriftsartikel (refereegranskat)abstract
- Early repolarization defined as antero-lateral ST-segment elevation exists in 1-2 % of the general population and has been considered a benign ECG finding for decades. However, early repolarization, defined as infero-lateral J-waves, has in recent studies been associated with an increased - albeit low - risk of sudden and cardiovascular death. This ECG pattern is present in 3-13% of the general population. However, exercise training can induce all types of early repolarization, and the prevalence in the athletic population rises to 20-90%. There is large variability between sports (higher in endurance athletes) and also throughout the season (higher during times of peak fitness). In athletes, early repolarization, regardless of type, is considered benign. In asymptomatic non-athletes, the absolute risk is too low to use this ECG finding in clinical practice. In individuals with J-wave syndrome, on the other hand, ICD implantation should be strongly considered to prevent sudden cardiac death.
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| 18. |
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| 19. |
- Aunes-Jansson, Maria, et al.
(författare)
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T wave inversions following ablation of 125 posteroseptal accessory pathways
- 2006
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Ingår i: Int J Cardiol. - : Elsevier BV. - 0167-5273. ; 106:1, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cardiac memory, electrophysiological remodeling induced by periods of altered ventricular activation, has been observed after resumption of normal activation following ablation of overt accessory pathways. We studied the occurrence and temporal characteristics of cardiac memory (inferior T wave inversions) after ablation of overt posteroseptal accessory pathways. METHODS: T wave changes were assessed in the frontal plane (leads II, aVF, and III) up to one year after the ablation in 125 consecutive patients. T wave polarity immediately after ablation was compared with the pre ablation delta wave polarity and the dominant QRS force in each lead. The number of inferior leads (0-3) with post ablation T wave changes (estimate of degree of cardiac memory) was analyzed in relation to estimates of the degree of preexcitation (accessory pathway refractoriness and QRS duration) prior to ablation. RESULTS: Electrocardiogram (ECG) signs of cardiac memory were present in 123 (98%) of the patients within one day after ablation. The post ablation T wave vector had the same direction as the vector of the pre-excited QRS complex (and delta wave) creating inferior T wave inversions. There was no correlation between the degree of preexcitation pre ablation and the extent of cardiac memory post ablation. A majority (about 90%) of ECGs recorded 3-6 months after the procedure, showed complete or almost complete normalization. CONCLUSIONS: T wave inversions were present in the vast majority of patients, persisted in some patients beyond 3 months, and might be misinterpreted as inferior wall ischemia.
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| 20. |
- Axelsson, Karl-Jonas, et al.
(författare)
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Hjärtats arbetsminne har trolig koppling till långt QT-syndrom
- 2019
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Ingår i: Läkartidningen. - 1652-7518. ; 116
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Tidskriftsartikel (refereegranskat)abstract
- Hjärtats arbetsminne synkroniserar och stabiliserar dess elektromekaniska funktion och tiden för kranskärlsgenomblödningen vid förändringar i hjärtfrekvensen. Långt QT-syndrom (LQTS) beror oftast på funktionsrubbningar i jonkanalproteiner som deltar i regleringen av hjärtats arbetsminne. Kunskaper om detta kan därför få betydelse för individualiserad behandling vid asymtomatiskt LQTS.
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| 21. |
- Bergfeldt, Lennart, 1950, et al.
(författare)
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Additional diagnostic testing for selected syncope patients.
- 2003
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Ingår i: The evaluation and treatment of syncope. A handbook for clinical practice. Benditt DG, Blanc J-J, Brignole M, Sutton R, eds.. - New York : Blackwell Publishing, Inc,/ Futura Division. ; , s. 96-101
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 22. |
- Bergfeldt, Lennart, 1950, et al.
(författare)
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Analysis of initial rhythm, witnessed status and delay to treatment among survivors of out-of-hospital cardiac arrest in Sweden.
- 2010
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Ingår i: Heart. - : BMJ Group. - 1355-6037 .- 1468-201X. ; 96:22, s. 1826-1830
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background The characteristics of patients who survive out-of-hospital cardiac arrest (OHCA) are incompletely known. The characteristics of survivors of OHCA during a period of 16 years in Sweden are described. Methods All the patients included in the Swedish Cardiac Arrest Registry between 1992 and 2007 in whom cardiopulmonary resuscitation was attempted and who were alive after 1 month were included in the survey. Results In all, 2432 survivors were registered. Information on initial rhythm at their first ECG recording was missing in 11%. Of the remaining 2165 survivors, 80% had a shockable rhythm and 20% had a non-shockable rhythm. Only a minority with a shockable rhythm among the bystander-witnessed cases were defibrillated within 5 min after cardiac arrest. This proportion did not change during the entry period. Among survivors found in a non-shockable rhythm, the majority were bystander-witnessed cases and a few had a delay from cardiac arrest to ambulance arrival of <5 min. Of all survivors, more women (27%) than men (18%) were found in a non-shockable rhythm (p<0.0001). During the 16 years in which the register was used for this study, the proportion of survivors found in a shockable rhythm did not change significantly. The cerebral performance categories score indicated better cerebral function among patients found in a shockable rhythm than in those found in a non-shockable rhythm. Conclusion Among survivors of OHCA, a substantial proportion was found in a non-shockable rhythm and this occurred more frequently in women than in men. The proportion of survivors found in a shockable rhythm has not changed markedly over time. Survivors found in a shockable rhythm had a better cerebral performance than survivors found in a non-shockable rhythm. The proportion of survivors who were bystander-witnessed and found in a shockable rhythm and defibrillated early is still remarkably low.
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| 23. |
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| 24. |
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| 25. |
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| 26. |
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| 27. |
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| 28. |
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| 29. |
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| 30. |
- Bergfeldt, Lennart, 1950, et al.
(författare)
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Miscellaneous diagnostic procedures: when are they indicated
- 2006
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Ingår i: The evaluation and treatment of syncope. A handbook for clinical practice. 2nd edition. Benditt DG, Blanc J-J, Brignole M, Sutton R, eds.. - New York : Blackwell Publishing. ; , s. 130-135
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 31. |
- Bergfeldt, Lennart, 1950
(författare)
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Repolarization variability - Friend or foe?
- 2016
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Ingår i: Journal of electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 49:2, s. 214-5
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Tidskriftsartikel (refereegranskat)
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| 32. |
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| 33. |
- Björck, Staffan, et al.
(författare)
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Atrial Fibrillation, Stroke Risk, and Warfarin Therapy Revisited: A Population-Based Study.
- 2013
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Ingår i: Stroke; a journal of cerebral circulation. - 1524-4628. ; 44, s. 3103-3108
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose—Atrial fibrillation (AF) is a major risk factor for ischemic stroke. This study aims to update the knowledge about AF and associated stroke risk and benefits of anticoagulation. Methods—We extracted data from the hospital, specialized outpatient, and primary healthcare and drug registries in a Swedish region with 1.56 million residents. We identified all individuals who had received an AF diagnosis during the previous 5 years; all stroke events during 2010; and patients with AF aged ≥50 years who had received warfarin during 2009. Results—AF had been diagnosed in 38 446 subjects who were alive at the beginning of 2010 (prevalence of 3.2% in the adult [≥20 years] population); ≈46% received warfarin therapy. In 2010, there were 4565 ischemic stroke events and 861 intracranial hemorrhages. AF had been diagnosed in 38% of ischemic events (≥50% among those aged ≥80 years) and in 23% of intracranial hemorrhages. An AF diagnosis was often lacking in hospital discharge records after stroke events. Warfarin therapy was associated with an odds ratio of 0.50 (confidence interval, 0.43–0.57) for ischemic stroke and, despite an increased risk of intracranial hemorrhage, an odds ratio of 0.57 (confidence interval, 0.50–0.64) for the overall risk for stroke. Conclusions—AF is more common than present guidelines suggest. The attributable risk of AF for ischemic stroke increases with age and is close to that of hypertension in individuals aged ≥80 years. Because a majority of patients with AF with increased risk for stroke had not received anticoagulation therapy, there is a large potential for improvement.
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| 34. |
- Blomström-Lundqvist, Carina, et al.
(författare)
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Effect of Catheter Ablation vs Antiarrhythmic Medication on Quality of Life in Patients With Atrial Fibrillation : The CAPTAF Randomized Clinical Trial
- 2019
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Ingår i: JAMIA Journal of the American Medical Informatics Association. - Chicago : American Medical Association (AMA). - 1067-5027 .- 1527-974X .- 0098-7484 .- 1538-3598. ; 321:11, s. 1059-1068
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Quality of life is not a standard primary outcome in ablation trials, even though symptoms drive the indication. OBJECTIVE To assess quality of life with catheter ablation vs antiarrhythmic medication at 12 months in patients with atrial fibrillation. DESIGN, SETTING, AND PARTICIPANTS Randomized clinical trial at 4 university hospitals in Sweden and 1 in Finland of 155 patients aged 30-70 years with more than 6 months of atrial fibrillation and treatment failure with 1 antiarrhythmic drug or beta-blocker, with 4-year follow-up. Study dateswere July 2008-September 2017. Major exclusionswere ejection fraction <35%, left atrial diameter > 60 mm, ventricular pacing dependency, and previous ablation. INTERVENTIONS Pulmonary vein isolation ablation (n= 79) or previously untested antiarrhythmic drugs (n= 76). MAIN OUTCOMES AND MEASURES Primary outcomewas the General Health subscale score (Medical Outcomes Study 36-Item Short-Form Health Survey) at baseline and 12 months, assessed unblinded (range, 0 [worst] to 100 [best]). There were 26 secondary outcomes, including atrial fibrillation burden (% of time) from baseline to 12 months, measured by implantable cardiac monitors. The first 3 months were excluded from rhythm analysis. RESULTS Among 155 randomized patients (mean age, 56.1 years; 22.6% women), 97% completed the trial. Of 79 patients randomized to receive ablation, 75 underwent ablation, including 2 who crossed over to medication and 14 who underwent repeated ablation procedures. Of 76 patients randomized to receive antiarrhythmic medication, 74 received it, including 8 who crossed over to ablation and 43 for whom the first drug used failed. General Health score increased from 61.8 to 73.9 points in the ablation group vs 62.7 to 65.4 points in the medication group (between-group difference, 8.9 points; 95% CI, 3.1-14.7; P=.003). Of 26 secondary end points, 5 were analyzed; 2 were null and 2 were statistically significant, including decrease in atrial fibrillation burden (from 24.9% to 5.5% in the ablation group vs 23.3% to 11.5% in the medication group; difference -6.8%[95% CI, -12.9% to -0.7%]; P=.03). Of the Health Survey subscales, 5 of 7 improved significantly. Most common adverse events were urosepsis (5.1%) in the ablation group and atrial tachycardia (3.9%) in the medication group. CONCLUSIONS AND RELEVANCE Among patients with symptomatic atrial fibrillation despite use of antiarrhythmic medication, the improvement in quality of life at 12 months was greater for those treated with catheter ablation compared with antiarrhythmic medication. Although the study was limited by absence of blinding, catheter ablation may offer an advantage for quality of life.
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| 35. |
- Blomström-Lundqvist, C, et al.
(författare)
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Hjärtrytmrubbningar
- 2009
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Ingår i: Läkemedelsboken. - : Apoteket AB. ; , s. 272-287
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 36. |
- Blomström-Lundqvist, C, et al.
(författare)
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Rytmrubbningar
- 2005
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Ingår i: Läkemedelsboken 2005/2006. - Stockholm : Apoteket AB. ; , s. 250-263
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 37. |
- Blomström-Lundqvist, C, et al.
(författare)
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Rytmrubbningar
- 2007
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Ingår i: Läkemedelsboken 2007/2008. - Sundbyberg : Stockholm Apoteket AB, Alfa Print. - 9185574570 ; , s. 254-267
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 38. |
- Boriani, Giuseppe, et al.
(författare)
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Safety and efficacy of dronedarone from clinical trials to real-world evidence : implications for its use in atrial fibrillation
- 2019
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Ingår i: Europace. - : Oxford University Press. - 1099-5129 .- 1532-2092. ; 21:12, s. 1764-1775
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Tidskriftsartikel (refereegranskat)abstract
- Efficacy and safety of dronedarone was shown in the ATHENA trial for paroxysmal or persistent atrial fibrillation (AF) patients. Further trials revealed safety concerns in patients with heart failure and permanent AF. This review summarizes insights from recent real-world studies and meta-analyses, including reports on efficacy, with focus on liver safety, mortality risk in patients with paroxysmal/persistent AF, and interactions of dronedarone with direct oral anticoagulants. Reports of rapidly progressing liver failure in dronedarone-prescribed patients in 2011 led to regulatory cautions about potential liver toxicity. Recent real-world evidence suggests dronedarone liver safety profile is similar to other antiarrhythmics and liver toxicity could be equally common with many Class III antiarrhythmics. Dronedarone safety concerns (increased mortality in patients with permanent AF) were raised based on randomized controlled trials (RCT) (ANDROMEDA and PALLAS), but comedication with digoxin may have increased the mortality rates in PALLAS, considering the dronedarone-digoxin pharmacokinetic (PK) interaction. Real-world data on apixaban-dronedarone interactions and edoxaban RCT observations suggest no significant safety risks for these drug combinations. Median trough plasma concentrations of dabigatran 110 mg during concomitant use with dronedarone are at acceptable levels, while PK data on the rivaroxaban-dronedarone interaction are unavailable. In RCTs and real-world studies, dronedarone significantly reduces AF burden and cardiovascular hospitalizations, and demonstrates a low risk for proarrhythmia in patients with paroxysmal or persistent AF. The concerns on liver safety must be balanced against the significant reduction in hospitalizations in patients with non-permanent AF and low risk for proarrhythmias following dronedarone treatment.
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| 39. |
- Borland, Maria, 1967, et al.
(författare)
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Effects of 3months of detraining following cardiac rehabilitation in patients with atrial fibrillation.
- 2022
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Ingår i: European review of aging and physical activity : official journal of the European Group for Research into Elderly and Physical Activity. - : Springer Science and Business Media LLC. - 1813-7253. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Atrial fibrillation negatively impacts physical fitness and health-related quality of life. We recently showed that 3months of physiotherapist-led exercise-based cardiac rehabilitation improves physical fitness and muscle function in elderly patients with permanent atrial fibrillation and concomitant diseases. Little is, however, known about the consequences for physical fitness, physical activity level, and health-related quality of life after ending the rehabilitation period.Prospective 3months follow-up study of 38 patients out of 40 eligible (10 women) who, as part of a randomized controlled trial, had completed a 3months physiotherapist-led cardiac rehabilitation resulting in improved physical fitness,. In the current study, the participants were instructed to refrain from exercise for 3months after completion of the rehabilitation period. Primary outcome measure was physical fitness measured as highest achieved workload using an exercise tolerance test. Secondary outcome measures were muscle function (muscle endurance tests), physical activity level (questionnaire and accelerometer), and health-related quality of life, (Short Form-36), as in the preceding intervention study. We used the Wilcoxon Signed Rank test to analyse differences between the end of rehabilitation and at follow-up. The effect size was determined using Cohen's d .Exercise capacity and exercise time significantly decresead between end of rehabilitation and at follow-up (p<.0001 for both). A significant reduction in shoulder flexion repetitions (p=.006) was observed as well as reduced health-related quality of life in the Short Form-36 dimensions Physical Function (p=.042), Mental Health (p=.030), and Mental Component Score (p=.035). There were, however, no changes regarding objective and subjective physical activity measurements.In older patients with permanent atrial fibrillation, previously achieved improvements from physiotherapist-led exercise-based cardiac rehabilitation in physical fitness and muscle function were lost, and health-related quality of life was impaired after ending the rehabilitation period. A strategy for conserving improvements after a rehabilitation period is essential.
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| 40. |
- Borland, Maria, 1967, et al.
(författare)
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Exercise-based cardiac rehabilitation improves physical fitness in patients with permanent atrial fibrillation - A randomized controlled study
- 2020
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Ingår i: Translational Sports Medicine. - : Hindawi Limited. - 2573-8488. ; 3:5, s. 415-425
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this multicenter randomized controlled trial was to compare physiotherapist-led exercise-based cardiac rehabilitation (PT-X) with physical activity on prescription (PAP) with regard to physical fitness, physical activity, health-related quality of life (HR-QoL), and metabolic risk markers in patients with permanent atrial fibrillation. Ninety six patients (28 women), age 74 (5) years, and ejection fraction >= 45% were randomized. An exercise tolerance test (primary outcome measure), muscle endurance tests, HR-QoL, physical activity assessments (questionnaire and accelerometer), and blood sampling were performed. The PT-X consisted of 60-minute group sessions and home-based exercise, both twice a week. The PAP consisted of 40 minutes of active walking, 4 times a week. Eighty seven patients completed the study. Exercise tolerance (maximum exercise capacity) improved significantly after PT-X (n = 40) but not after PAP (n = 47) (16 vs -3 W; P < .0001). Muscle endurance also improved after PT-X: shoulder flexion left arm (7 vs -1 repetition; P < .001), heel-lift right leg (4 vs 1 repetition; P < .05), left leg (4 vs -1 repetition; P < .001), and shoulder abduction (17 vs -4 s; P < .010). PAP significantly increased energy expenditure. Health-related quality of life and lab-tests did not differ. PT-X improved physical fitness in patients with permanent atrial fibrillation.
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| 41. |
- Braunschweig, Frieder, et al.
(författare)
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Paroxysmal regular supraventricular tachycardia: the diagnostic accuracy of the transesophageal ventriculo-atrial interval.
- 2011
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Ingår i: Annals of Noninvasive Electrocardiology. - 1542-474X. ; 16:4, s. 327-335
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To establish the diagnostic accuracy of the transesophageal ventriculo-atrial (VA) interval in patients with paroxysmal supraventricular tachycardia (PSVT) and normal baseline electrocardiogram (ECG). Methods: The transesophageal VA interval during tachycardia was recorded in 318 patients (age 45 ± 17 years, 58% female) with PSVT and a normal surface ECG between attacks. Subsequently, all patients underwent an ablation procedure establishing the correct tachycardia diagnosis. Results: AV nodal reentrant tachycardia (AVNRT), AV reentrant tachycardia through a concealed accessory pathway (AVRT), and ectopic atrial tachycardia (EAT) were found in 213, 95, and 10 cases, respectively. Receiver operating characteristic curve analysis identified an optimal cutoff for a binary categorization of AVNRT versus AVRT/EAT at ≤80 ms (area under the curve 0.891). Owing to a biphasic distribution, AVNRT was very likely at VA intervals ≤90 ms with a sensitivity, specificity, and positive predictive value (PPV) of 87%, 91%, and 95%. In the range 91–160 ms the corresponding values for AVRT were 88%, 95%, and 88% (90%, 99%, and 98% in male patients). In the small group with VA intervals >160 ms (n = 29), the diagnosis was less clear (PPV of 67% for AVNRT). Conclusions: In patients with sudden onset regular tachycardia and a normal ECG during sinus rhythm, a transesophageal VA interval of ≤80 ms has the highest diagnostic accuracy to diagnose AVNRT versus AVRT/EAT. Overall, the biphasic distribution of VA intervals suggests considering AVNRT at 90 ms and below and AVRT between 91 and 160 ms (in particular in male patients) while the diagnosis is vague at VA intervals above 160 ms.
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| 42. |
- Braunschweig, Frieder, et al.
(författare)
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Transient repolarization instability following the initiation of cardiac resynchronization therapy.
- 2011
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Ingår i: EP Europace. - : Oxford University Press (OUP). - 1532-2092. ; 13:9, s. 1327-1334
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Tidskriftsartikel (refereegranskat)abstract
- Aims Cardiac resynchronization therapy (CRT) may cause changes in ventricular repolarization (VR), particularly in the initial phase of treatment. This study investigated the effect of CRT cessation and re-initiation on parameters of VR duration and heterogeneity at different paced heart rates. Methods Cardiac resynchronization therapy was inactivated for 2 weeks in 16 treatment responders to CRT. QT and JT intervals were measured on the surface electrocardiogram at 60, 70, and 80 bpm (randomized order) and vectorcardiography (VCG) was performed with CRT ‘on’ (day 0), ‘off’ (day 0, 1, 7, and 14) and after CRT re-initiation (day 14, 15, 16, and 21). On day 0 (‘on’) and 14 (‘off’) echocardiography, the 6 min walking distance and brain natriuretic peptide were assessed. Results The QT interval at baseline (CRT ‘on’), measured at 60, 70, and 80 bpm, was 482 ± 31, 468 ± 37, and 457 ± 39 ms, respectively, and decreased by 5, 5, and 6% during the first week following CRT cessation (all P< 0.05). Immediately after re-initiation on day 14, it increased again by 20 ± 18 (4%; P< 0.05), 34 ± 39 (8%; P< 0.01), and 16 ± 38 ms (4%, ns) followed by a gradual decrease towards previous ‘off’ levels. Similar changes were observed for the JT interval. Ventricular repolarization duration was significantly shortened by increasing the paced heart rate from 60 to 70 and 80 bpm. Vectorcardiography parameters reflecting VR gradients (ST-vector magnitude, Tarea, and Tavplan) increased significantly (by 31, 45, and 71%) after CRT cessation. A similar but non-significant pattern was observed after CRT re-initiation. Conclusion The increase in repolarization duration and gradients observed after CRT initiation suggests a transient state of VR instability that can be attenuated by programming of higher paced heart rates during the initial phase of treatment.
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| 43. |
- Brignole, M., et al.
(författare)
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Comparative assessment of right, left, and biventricular pacing in patients with permanent atrial fibrillation
- 2005
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Ingår i: Eur Heart J. - 0195-668X. ; 26:7, s. 712-22
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Left ventricular (LV) and biventricular (BiV) pacing are potentially superior to right ventricular (RV) apical pacing in patients undergoing atrioventricular (AV) junction ablation and pacing for permanent atrial fibrillation. METHODS AND RESULTS: Prospective randomized, single-blind, 3-month crossover comparison between RV and LV pacing (phase 1) and between RV and BiV pacing (phase 2) performed in 56 patients (70+/-8 years, 34 males) affected by severely symptomatic permanent atrial fibrillation, uncontrolled ventricular rate, or heart failure. Primary endpoints were quality of life and exercise capacity. Compared with RV pacing, the Minnesota Living with Heart Failure Questionnaire (LHFQ) score improved by 2 and 10% with LV and BiV pacing, respectively, the effort dyspnoea item of the Specific Symptom Scale (SSS) changed by 0 and 2%, the Karolinska score by 6 and 14% (P<0.05 for BiV), the New York Heart Association (NYHA) class by 5 and 11% (P<0.05 for BiV), the 6-min walked distance by 12 (+4%) and 4 m (+1%), and the ejection fraction by 5 and 5% (P<0.05 for both). BiV pacing but not LV pacing was slightly better than RV pacing in the subgroup of patients with preserved systolic function and absence of native left bundle branch block. Compared with pre-ablation measures, the Minnesota LHFQ score improved by 37, 39, and 49% during RV, LV, and BiV pacing, respectively, the effort dyspnoea item of the SSS by 25, 25, and 39%, the Karolinska score by 39, 42, and 54%, the NYHA class by 21, 25, and 30%, the 6-min walking distance by 35 (12%), 47 (16%), and 51 m (19%) and the ejection fraction by 5, 10, and 10% (all differences P<0.05). CONCLUSIONS: Rhythm regularization achieved with AV-junction ablation improved quality of life and exercise capacity with all modes of pacing. LV and BiV pacing provided modest or no additional favourable effect compared with RV pacing.
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| 44. |
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| 45. |
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| 46. |
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| 47. |
- Chaudhry, U., et al.
(författare)
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Idiopathic ventricular fibrillation – Long term prognosis in relation to clinical findings and ECG patterns in a Swedish cohort
- 2019
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Ingår i: Journal of Electrocardiology. - Philadephia : Churchill Livingstone Inc. Medical Publishers. - 0022-0736 .- 1532-8430. ; 56, s. 46-51
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Tidskriftsartikel (refereegranskat)abstract
- Background: Idiopathic ventricular fibrillation (IVF) is a rare cause of sudden cardiac arrest which may pose therapeutic and prognostic challenges. To date, the only effective treatment for survivors of cardiac arrest is the insertion of an implantable cardioverter-defibrillator (ICD). We sought to review the long-term outcome of a Swedish cohort with IVF.Methods and results: Fifty patients with IVF diagnosis between 1988 and 2016 (mean age at index 34.3, 56% male), were followed for a median 13.8 years in this retrospective multicenter observational study. No cardiac mortality was reported. 32% (n = 16) of patients had recurrence of ventricular fibrillation or sustained ventricular tachycardia, requiring ICD therapy, at a median time of 1.9 years (range 0.1–20.3) from the index event. Annual incidence rate of ventricular tachyarrhythmia was 3.1%. Abnormal ECG at baseline did not predict appropriate ICD therapy (p = 0.56). During the follow-up period, 14% (n = 7) patients received a cardiac diagnosis. Follow-up genetic testing was low (26%), however did confirm pathogenic mutations in three cases.Conclusion: Idiopathic VF is a rare diagnosis with a relatively good prognosis provided ICD therapy is initiated. Routine clinical follow-up is recommended due to potential late emerging cardiac pathology. ECG changes are common, but have no prognostic value in determining the risk of ventricular arrhythmias recurrence. Screening for genetic diseases has previously been low, and this calls for improvement, especially since cheaper and more comprehensive genetic panels are now readily available.
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| 48. |
- Dahlberg, Pia, et al.
(författare)
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QT correction using Bazett's formula remains preferable in long QT syndrome type 1 and 2
- 2021
-
Ingår i: Annals of Noninvasive Electrocardiology. - : John Wiley & Sons. - 1082-720X .- 1542-474X. ; 26:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The heart rate (HR) corrected QT interval (QTc) is crucial for diagnosis and risk stratification in the long QT syndrome (LQTS). Although its use has been questioned in some contexts, Bazett's formula has been applied in most diagnostic and prognostic studies in LQTS patients. However, studies on which formula eliminates the inverse relation between QT and HR are lacking in LQTS patients. We therefore determined which QT correction formula is most appropriate in LQTS patients including the effect of beta blocker therapy and an evaluation of the agreement of the formulae when applying specific QTc limits for diagnostic and prognostic purposes.Methods: Automated measurements from routine 12-lead ECGs from 200 genetically confirmed LQTS patients from two Swedish regions were included (167 LQT1, 33 LQT2). QT correction was performed using the Bazett, Framingham, Fridericia, and Hodges formulae. Linear regression was used to compare the formulae in all patients, and before and after the initiation of beta blocking therapy in a subgroup (n = 44). Concordance analysis was performed for QTc >= 480 ms (diagnosis) and >= 500 ms (prognosis).Results: The median age was 32 years (range 0.1-78), 123 (62%) were female and 52 (26%) were children <= 16 years. Bazett's formula was the only method resulting in a QTc without relation with HR. Initiation of beta blocking therapy did not alter the result. Concordance analyses showed clinically significant differences (Cohen's kappa 0.629-0.469) for diagnosis and prognosis in individual patients.Conclusion: Bazett's formula remains preferable for diagnosis and prognosis in LQT1 and 2 patients.
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| 49. |
- Danielsson, B., et al.
(författare)
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Drug use and torsades de pointes cardiac arrhythmias in Sweden: a nationwide register-based cohort study
- 2020
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Objective To study the occurrence of torsades de pointes (TdP) ventricular tachycardia in relation to use of drugs labelled with TdP risk, using two nationwide Swedish registers. Design Prospective register-based cohort study. Setting Entire Sweden. Participants Persons aged >= 18 years prescribed and dispensed any drug classified with TdP risk during 2006-2017, according to CredibleMeds. Persons with a registered TdP diagnosis during the study period, using drugs labelled with known (TdP 1), possible (TdP 2) or conditional (TdP 3) risk at the incident of TdP were examined. Primary outcome measures Occurrence of TdP in relation to exposure rates for individual drugs with TdP risk. Secondary outcome measures Concurrent use of more than one TdP-labelled drug in a person with a TdP diagnosis. Results During the study period, 410 TdP cases using drugs with TdP risk labels at the incident were registered; 205 women and 205 men, mean age 74.0 and 71.5 years, respectively. Antidepressants dominated (129/410, 30%), followed by antiarrhythmics (17%). Diuretics and gastric acid-secretion inhibitors, with TdP risk related to induction of hypokalaemia or hypomagnesaemia, were used in 56% and 32% of the 410 TdP cases, respectively. Among the most used antidepressants, citalopram with known TdP 1 risk was associated with both a higher absolute number and incidence of TdP per 100 000 users (two to four times), compared with mirtazapine with possible (TdP 2), and sertraline with conditional (TdP 3) risk. Multiple risk factors, including advanced age, cardiovascular disease and treatment with more than one TdP-classified drug, were frequently observed. Conclusions Antidepressants followed by antiarrhythmics dominated among TdP risk drugs used by adults with TdP diagnosis, the majority being >= 65 years. TdP risk class and concomitant medication should be considered when prescribing antidepressants to older patients.
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| 50. |
- Diamant, Ulla-Britt, 1955-, et al.
(författare)
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Electrophysiological phenotype in the LQTS mutations Y111C and R518X in the KCNQ1 gene
- 2013
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Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 115:10, s. 1423-1432
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Tidskriftsartikel (refereegranskat)abstract
- Long QT syndrome is the prototypical disorder of ventricular repolarization (VR), and a genotype-phenotype relation is postulated. Furthermore, although increased VR heterogeneity (dispersion) may be important in the arrhythmogenicity in long QT syndrome, this hypothesis has not been evaluated in humans and cannot be tested by conventional electrocardiography. In contrast, vectorcardiography allows assessment of VR heterogeneity and is more sensitive to VR alterations than electrocardiography. Therefore, vectorcardiography was used to compare the electrophysiological phenotypes of two mutations in the LQT1 gene with different in vitro biophysical properties, and with LQT2 mutation carriers and healthy control subjects. We included 99 LQT1 gene mutation carriers (57 Y111C, 42 R518X) and 19 LQT2 gene mutation carriers. Potassium channel function is in vitro most severely impaired in Y111C. The control group consisted of 121 healthy subjects. QRS, QT, and T-peak to T-end (Tp-e) intervals, measures of the QRS vector and T vector and their relationship, and T-loop morphology parameters were compared at rest. Apart from a longer heart rate-corrected QT interval (QT heart rate corrected according to Bazett) in Y111C mutation carriers, there were no significant differences between the two LQT1 mutations. No signs of increased VR heterogeneity were observed among the LQT1 and LQT2 mutation carriers. QT heart rate corrected according to Bazett and Tp-e were longer, and the Tp-e-to-QT ratio greater in LQT2 than in LQT1 and the control group. In conclusion, there was a marked discrepancy between in vitro potassium channel function and in vivo electrophysiological properties in these two LQT1 mutations. Together with previous observations of the relatively low risk for clinical events in Y111C mutation carriers, our results indicate need for cautiousness in predicting in vivo electrophysiological properties and the propensity for clinical events based on in vitro assessment of ion channel function alone.
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