| 1. |
- Memarian, Ensieh, et al.
(författare)
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Associations between physical activity and autonomic function during deep breathing test : the Swedish CArdioPulmonary bioImage Study (SCAPIS).
- 2023
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Ingår i: Clinical Autonomic Research. - : Springer. - 0959-9851 .- 1619-1560. ; 33:4, s. 411-420
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The deep breathing test (DBT) is a sensitive test of cardiovagal function. The aim of this study was to explore associations between physical activity and sedentary time, measured by accelerometer, and autonomic function, using DBT.METHODS: In the Swedish Cardio-Pulmonary bioImage Study, men and women aged 50-64 were randomly invited from the general population. A total of 4325 subjects who underwent DBT and assessment of physical activity and sedentary time by accelerometery were included. ECG files from 1-min DBT were used to calculate measures of respiratory sinus arrhythmia [RSA; expiration-inspiration (E-I) difference and E/I ratio], heart rate variability [HRV; root mean square of successive differences (RMSSD), standard deviation of heart rates and mean circular resultant]. Low RSA and HRV was defined as the lowest 10% in the population.RESULTS: For accelerometer-assessed physical activity, there were significant associations between high percentage of sedentary time and low E/I (p < 0.01), and low RMSSD (p < 0.01) in an age- and sex-adjusted model, and between percentage of sedentary time and low RMSSD (p = 0.04) in a risk factor-adjusted model. Low RMSSD was less common in those with a high percentage of moderate to vigorous physical activity (p = 0.04, after risk-factor adjustment). These associations became non-significant when further adjusting for heart rate.CONCLUSION: We report associations between degree of physical activity and indices of autonomic dysfunction in a large population. The relationships were no longer significant after adjustments for heart rate, indicating that the relationship between physical activity and cardiovagal function partly is accounted for by reduced heart rate.
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| 2. |
- Stokke, Mathis K, et al.
(författare)
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Absence of ECG task force criteria does not rule out structural changes in genotype positive ARVC patients
- 2020
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Ingår i: International Journal of Cardiology. - : Elsevier. - 0167-5273 .- 1874-1754. ; 317, s. 152-158
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: In Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC), electrophysiological pathology has been claimed to precede morphological and functional pathology. Accordingly, an ECG without ARVC markers should be rare in ARVC patients with pathology identified by cardiac imaging. We quantified the prevalence of ARVC patients with evidence of structural disease, yet without ECG Task Force Criteria (TFC).METHODS AND RESULTS: We included 182 probands and family members with ARVC-associated mutations (40 ± 17 years, 50% women, 73% PKP2 mutations) from the Nordic ARVC Registry in a cross-sectional analysis. For echocardiography and cardiac MR (CMR), we differentiated between "abnormalities" and TFC. "Abnormalities" were defined as RV functional or structural measures outside TFC reference values, without combinations required to fulfill TFC. ECG TFC were used as defined, as these are not composite parameters. We found that only 4% of patients with ARVC fulfilled echocardiographic TFC without any ECG TFC. However, importantly, 38% of patients had imaging abnormalities without any ECG TFC. These results were supported by CMR data from a subset of 51 patients: 16% fulfilled CMR TFC without fulfilling ECG TFC, while 24% had CMR abnormalities without any ECG TFC. In a multivariate analysis, echocardiographic TFC were associated with arrhythmic events.CONCLUSION: More than one third of ARVC genotype positive patients had subtle imaging abnormalities without fulfilling ECG TFC. Although most patients will have both imaging and ECG abnormalities, structural abnormalities in ARVC genotype positive patients cannot be ruled out by the absence of ECG TFC.
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| 3. |
- Platonov, Pyotr, et al.
(författare)
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Permanent atrial fibrillation in patients without structural heart disease is not associated with signs of infection by Chlamydia pneumoniae and Helicobacter pylori.
- 2008
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Ingår i: Acta Cardiologica. - 0001-5385. ; 63:4, s. 479-484
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The objective of this study was to explore the role of Chlamydia pneumoniae and Helicobacter pylori infections in patients with idiopathic permanent atrial fibrillation. METHODS AND RESULTS: Sera from 72 patients with permanent atrial fibrillation without structural heart disease (mean age 69.6 years, 23 women) were analysed for IgG antibodies against Chlamydia pneumoniae and Helicobacter pylori and compared in a I:I age- and sex-matched case:control manner with those pooled from a healthy reference population of 72 individuals from the same geographical area. After excluding patients with other possible or definite factors known either to cause atrial fibrillation or to affect the prevalence of seropositivity to these agents, the frequency of seropositivity due to one or both of the infectious agents was compared. Serum C-reactive protein (CRP) level was assessed using immunoturbidimetry technique. Both agents were equally common in men and women. Neither seropositivity to Chlamydia pneumoniae (76% vs. 83%, patients vs. control subjests, ns) nor to Helicobacter pylori (57% contra 55%, patients vs. controls, ns) alone reached significance in the comparisons between patients with atrial fibrillation and control subjects. Serum CRP was higher in patients with AF (5.3 mg/L vs. 2.8 mg/L, P < 0.001). CONCLUSIONS: Though presence of permanent AF is associated with elevated CRP levels, this elevation is not the result of earlier infections with Chlamydia pneumoniae or Helicobacter pylori or their combination.
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| 4. |
- Andlauer, Robin, et al.
(författare)
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Influence of left atrial size on P-wave morphology : differential effects of dilation and hypertrophy
- 2018
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Ingår i: Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology. - : Oxford University Press (OUP). - 1532-2092. ; 20:3, s. 36-44
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Chronic left atrial enlargement (LAE) increases the risk of atrial fibrillation. Electrocardiogram (ECG) criteria might provide a means to diagnose LAE and identify patients at risk; however, current criteria perform poorly. We seek to characterize the potentially differential effects of atrial dilation vs. hypertrophy on the ECG P-wave. Methods and results: We predict effects on the P-wave of (i) left atrial dilation (LAD), i.e. an increase of LA cavity volume without an increase in myocardial volume, (ii) left atrial concentric hypertrophy (LACH), i.e. a thickened myocardial wall, and (iii) a combination of the two. We performed a computational study in a cohort of 72 anatomical variants, derived from four human atrial anatomies. To model LAD, pressure was applied to the LA endocardium increasing cavity volume by up to 100%. For LACH, the LA wall was thickened by up to 3.3 mm. P-waves were derived by simulating atrial excitation propagation and computing the body surface ECG. The sensitivity regarding changes beyond purely anatomical effects was analysed by altering conduction velocity by 25% in 96 additional model variants. Left atrial dilation prolonged P-wave duration (PWd) in two of four subjects; in one subject a shortening, and in the other a variable change were seen. Left atrial concentric hypertrophy, in contrast, consistently increased P-wave terminal force in lead V1 (PTF-V1) in all subjects through an enlarged amplitude while PWd was unaffected. Combined hypertrophy and dilation generally enhanced the effect of hypertrophy on PTF-V1. Conclusion: Isolated LAD has moderate effects on the currently used P-wave criteria, explaining the limited utility of PWd and PTF-V1 in detecting LAE in clinical practice. In contrast, PTF-V1 may be a more sensitive indicator of LA myocardial hypertrophy.
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| 5. |
- Axelsson, Jimmy, et al.
(författare)
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Ejection fraction in left bundle branch block is disproportionately reduced in relation to amount of myocardial scar
- 2018
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 0022-0736 .- 1532-8430. ; 51:6, s. 1071-1076
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The relationship between left ventricular (LV) ejection fraction (EF) and LV myocardial scar can identify potentially reversible causes of LV dysfunction. Left bundle branch block (LBBB) alters the electrical and mechanical activation of the LV. We hypothesized that the relationship between LVEF and scar extent is different in LBBB compared to controls. Methods: We compared the relationship between LVEF and scar burden between patients with LBBB and scar (n = 83), and patients with chronic ischemic heart disease and scar but no electrocardiographic conduction abnormality (controls, n = 90), who had undergone cardiovascular magnetic resonance (CMR) imaging at one of three centers. LVEF (%) was measured in CMR cine images. Scar burden was quantified by CMR late gadolinium enhancement (LGE) and expressed as % of LV mass (%LVM). Maximum possible LVEF (LVEFmax) was defined as the function describing the hypotenuse in the LVEF versus myocardial scar extent scatter plot. Dysfunction index was defined as LVEFmax derived from the control cohort minus the measured LVEF. Results: Compared to controls with scar, LBBB with scar had a lower LVEF (median [interquartile range] 27 [19–38] vs 36 [25–50] %, p < 0.001), smaller scar (4 [1–9] vs 11 [6–20] %LVM, p < 0.001), and greater dysfunction index (39 [30–52] vs 21 [12–35] % points, p < 0.001). Conclusions: Among LBBB patients referred for CMR, LVEF is disproportionately reduced in relation to the amount of scar. Dyssynchrony in LBBB may thus impair compensation for loss of contractile myocardium.
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| 6. |
- Loewe, Axel, et al.
(författare)
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Left and Right Atrial Contribution to the P-wave in Realistic Computational Models
- 2015
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Ingår i: Lecture Notes in Computer Science. - Cham : Springer International Publishing. - 0302-9743 .- 1611-3349. ; 9126, s. 439-447
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Konferensbidrag (refereegranskat)abstract
- ECG markers derived from the P-wave are used frequently to assess atrial function and anatomy, e.g. left atrial enlargement. While having the advantage of being routinely acquired, the processes underlying the genesis of the P-wave are not understood in their entirety. Particularly the distinct contributions of the two atria have not been analyzed mechanistically. We used an in silico approach to simulate P-waves originating from the left atrium (LA) and the right atrium (RA) separately in two realistic models. LA contribution to the P-wave integral was limited to 30% or less. Around 20% could be attributed to the first third of the P-wave which reflected almost only RA depolarization. Both atria contributed to the second and last third with RA contribution being about twice as large as LA contribution. Our results foster the comprehension of the difficulties related to ECG-based LA assessment.
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| 7. |
- Karlsson, Mattias, et al.
(författare)
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Drug Dependent Circadian Variations in AV-nodal Properties During Atrial Fibrillation
- 2022
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Ingår i: 2022 Computing in Cardiology, CinC 2022. - 2325-8861 .- 2325-887X. - 9798350300970 ; 2022-September
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Konferensbidrag (refereegranskat)abstract
- The heart rate during atrial fibrillation (AF) is highly dependent on the conduction properties of the atrioventricular (AV) node, which can be affected using β-blockers or calcium channel blockers, often chosen empirically. Thus, characterization of the AV nodal conduction properties could contribute to personalized treatment of AF. We have created a mathematical network model of the AV node where continuous estimation of the refractory period and conduction delay from 24-hour ambulatory ECGs from patients with permanent AF (n=59) was achieved using a problem-specific genetic algorithm. Circadian variations in the resulting model parameter trends were quantified using cosinor analysis, and differences between treatment with β-blockers and calcium blockers were assessed using a linear-mixed effect approach. The mixed-effects analysis indicated increased refractoriness relative to baseline for all drugs. For the β-blockers, an additional decrease in circadian variation for parameters representing conduction delay was observed. This indicates that the two drug types have quantifiable differences in their effects on AV-nodal conduction properties. The proposed method enables analysis of circadian variation in AV node conduction delay and refractoriness from 24h ambulatory ECG, which can be used to monitor and possibly predict the effect of rate control drugs.
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| 8. |
- Plappert, Felix, et al.
(författare)
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Tilt-Induced Changes in RR Series Characteristics : An AV Node Simulation Study
- 2022
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Ingår i: 2022 Computing in Cardiology, CinC 2022. - 2325-8861 .- 2325-887X. - 9798350300970 - 9798350310139 ; 2022-September
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Konferensbidrag (refereegranskat)abstract
- In the ECG recordings during tilt test, changes in RR series characteristics can be observed. The purpose of the present study is to investigate to what extent these changes can be explained by changes in the atrial input and in the atrioventricular (AV) nodal characteristics induced by the autonomic nervous system (ANS). Average RR series characteristics (mean, rmssd and sample entropy) and average atrial fibrillatory rate (AFR) were obtained from 24 patients during supine, head-down tilt (HDT), and head-up tilt (HUT). Simulations were performed using an AV node model consisting of a network of interacting node; each node with a refractory period (R) and conduction delay (D) dependent on the stimulation history. In an extension to the AV node model, R and D were scaled to account for ANS induced changes and simulations were performed with the original and extended model, respectively. The atrial impulse series entering the AV node was modelled as a point process with time-varying mean and std determined by the AFR. The clinical RR mean, RR rmssd and RR sample entropy decreased from supine to HDT and decreased further from HDT to HUT. Simulation results indicate that the model must account for ANS-induced changes to replicate the observed response in RR series characteristics, while alterations in the atrial input alone are insufficient to replicate the response.
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| 9. |
- Fenner, Merle Friederike, et al.
(författare)
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Effect of selective IK,ACh inhibition by XAF-1407 in an equine model of tachypacing-induced persistent atrial fibrillation
- 2020
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Ingår i: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 177:16, s. 3778-3794
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose: Inhibition of the G-protein gated ACh-activated inward rectifier potassium current, IK,ACh may be an effective atrial selective treatment strategy for atrial fibrillation (AF). Therefore, the anti-arrhythmic and electrophysiological properties of a novel putatively potent and highly specific IK,ACh inhibitor, XAF-1407 (3-methyl-1-[5-phenyl-4-[4-(2-pyrrolidin-1-ylethoxymethyl)-1-piperidyl]thieno[2,3-d]pyrimidin-6-yl]azetidin-3-ol), were characterised for the first time in vitro and investigated in horses with persistent AF. Experimental Approach: The pharmacological ion channel profile of XAF-1407 was investigated using cell lines expressing relevant ion channels. In addition, eleven horses were implanted with implantable cardioverter defibrillators enabling atrial tachypacing into self-sustained AF. The electrophysiological effects of XAF-1407 were investigated after serial cardioversions over a period of 1 month. Cardioversion success, drug-induced changes of atrial tissue refractoriness, and ventricular electrophysiology were assessed at baseline (day 0) and days 3, 5, 11, 17, and 29 after AF induction. Key Results: XAF-1407 potently and selectively inhibited Kir3.1/3.4 and Kir3.4/3.4, underlying the IK,ACh current. XAF-1407 treatment in horses prolonged atrial effective refractory period as well as decreased atrial fibrillatory rate significantly (~20%) and successfully cardioverted AF, although with a decreasing efficacy over time. XAF-1407 shortened atrioventricular-nodal refractoriness, without effect on QRS duration. QTc prolongation (4%) within 15 min of drug infusion was observed, however, without any evidence of ventricular arrhythmia. Conclusion and Implications: XAF-1407 efficiently cardioverted sustained tachypacing-induced AF of short duration in horses without notable side effects. This supports IK,ACh inhibition as a potentially safe treatment of paroxysmal AF in horses, suggesting potential clinical value for other species including humans.
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| 10. |
- Buhl, Rikke, et al.
(författare)
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Atrial fibrillatory rate as predictor of recurrence of atrial fibrillation in horses treated medically or with electrical cardioversion
- 2022
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Ingår i: Equine Veterinary Journal. - : Wiley. - 0425-1644 .- 2042-3306. ; 54:6, s. 1013-1022
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Tidskriftsartikel (refereegranskat)abstract
- Background: The recurrence rate of atrial fibrillation (AF) in horses after cardioversion to sinus rhythm (SR) is relatively high. Atrial fibrillatory rate (AFR) derived from surface ECG is considered a biomarker for electrical remodelling and could potentially be used for the prediction of successful AF cardioversion and AF recurrence. Objectives: Evaluate if AFR was associated with successful treatment and could predict AF recurrence in horses. Study design: Retrospective multicentre study. Methods: Electrocardiograms (ECG) from horses with persistent AF admitted for cardioversion with either medical treatment (quinidine) or transvenous electrical cardioversion (TVEC) were included. Bipolar surface ECG recordings were analysed by spatiotemporal cancellation of QRST complexes and calculation of AFR from the remaining atrial signal. Kaplan-Meier survival curve and Cox regression analyses were performed to assess the relationship between AFR and the risk of AF recurrence. Results: Of the 195 horses included, 74 received quinidine treatment and 121 were treated with TVEC. Ten horses did not cardiovert to SR after quinidine treatment and AFR was higher in these, compared with the horses that successfully cardioverted to SR (median [interquartile range]), (383 [367-422] vs 351 [332-389] fibrillations per minute (fpm), P <.01). Within the first 180 days following AF cardioversion, 12% of the quinidine and 34% of TVEC horses had AF recurrence. For the horses successfully cardioverted with TVEC, AFR above 380 fpm was significantly associated with AF recurrence (hazard ratio = 2.4, 95% confidence interval 1.2-4.8, P =.01). Main limitations: The treatment groups were different and not randomly allocated, therefore the two treatments cannot be compared. Medical records and the follow-up strategy varied between the centres. Conclusions: High AFR is associated with failure of quinidine cardioversion and AF recurrence after successful TVEC. As a noninvasive marker that can be retrieved from surface ECG, AFR can be clinically useful in predicting the probability of responding to quinidine treatment as well as maintaining SR after electrical cardioversion.
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