| 1. |
- Holmqvist, Fredrik, et al.
(författare)
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Indices of electrical and contractile remodeling during atrial fibrillation in man
- 2006
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 29:5, s. 512-519
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Tidskriftsartikel (refereegranskat)abstract
- Atrial electrical and contractile remodeling have been demonstrated to coincide during atrial fibrillation (AF) in experimental studies. We explored whether electrical and contractile remodeling correlate in man and explored its clinical implications. METHODS: Forty-nine patients with persistent AF were studied. Electrical remodeling was assessed noninvasively using spectral analysis to estimate the average fibrillatory rate (AFR). Atrial contractility was assessed by transesophageal echocardiography (TEE) measurement of left atrial appendage outflow velocity (LAAOV). RESULTS: The AFR was 403+/-43 fibrillations per minute (fpm) and the LAAOV was 0.27+/-0.14 m/s. A significant correlation was found between AFR and LAAOV (r=-0.47, P=0.001). In patients with a LAAOV>or=0.25 m/s, the AFR was 387+/-48 fpm compared to 419+/-31 fpm among patients with LAAOV<0.25 m/s (P<0.01). CONCLUSIONS: This study demonstrates that indices of electrical and contractile remodeling are strongly correlated in persistent AF in man. The interindividual overlap, however, is too large to allow predictions of LAAOV based on fibrillatory frequency alone.
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| 2. |
- Holmqvist, Fredrik, et al.
(författare)
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Noninvasive evidence of shortened atrial refractoriness during sinus rhythm in patients with paroxysmal atrial fibrillation.
- 2009
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 32:3, s. 302-307
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Shortening of the atrial refractory period is the key feature of atrial electrical remodeling during atrial fibrillation (AF). During sinus rhythm (SR), assessment of the atrial refractoriness is hampered by the fact that the atrial repolarization wave (Ta wave) is largely obscured by the following QRST complex. The purpose of this study was to study the Ta wave in subjects with paroxysmal AF during SR with third-degree atrioventricular (AV) block, and in matched controls. METHODS: Fifteen patients (mean age 70 +/- 10 years, five males) with paroxysmal AF undergoing AV-nodal ablation were studied. Fifteen age- and gender-matched subjects (mean age 71 +/- 9 years, five males) with third-degree AV block, without a history of heart disease, were used as controls. Standard 12-lead electrocardiograms (ECGs) were recorded and transformed to orthogonal leads and studied using P-wave signal averaging technique. RESULTS: The P to Ta interval was shorter (408 +/- 47 ms vs 451 +/- 53 ms, P = 0.017) and in Lead Y the Ta peak location was earlier (156 +/- 31 ms vs 187 +/- 34 ms, P = 0.002) in subjects with paroxysmal AF than in the controls. The P-wave duration (126 +/- 15 ms vs 129 +/- 17 ms, P = 0.59) and morphology was similar in AF patients and controls. CONCLUSIONS: In this study, the ECG signs of shorter atrial refractoriness associated with a history of AF are visualized for the first time during SR. The finding of the earlier location of the PTa peak in AF subjects implies that a possible indicator of increased arrhythmia susceptibility may be visible already in the unprocessed ECG.
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| 3. |
- Husser, D, et al.
(författare)
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Determinants and prognostic significance of immediate atrial fibrillation recurrence following cardioversion in patients undergoing pulmonary vein isolation
- 2005
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 28:2, s. 119-125
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Tidskriftsartikel (refereegranskat)abstract
- Background: Immediate recurrence of atrial fibrillation (IRAF) occurs frequently after electrical cardioversion, its electrophysiological determinants and prognostic significance hove, however, not been studied in detail. This Study aimed to explore (1) the association of IRAF with clinical characteristics, pulmonary vein (PV) arrhythmogenicity as well as atrial electrophysiologic properties and (2) the prognostic significance of IRAF for outcome of PV isolation for atrial fibrillation (AF). Methods and Results: The subjects of this study were 41 consecutive patients (30 males, 11 females) who underwent PV isolation for drug-refroctory AF. Following successful initial cordioversion, 19 patients (46%) had IRAF within 2 minutes. Coupling intervals of AF reinitiating beats arising from PVs were shorter (386 +/- 39 vs 490 +/- 136 ms, P=0.008) and prematurity indices (0.38 +/- 0.06 vs 0.51 +/- 0.12, P=0.01) smaller than those of premature beats not initiating AF Patients with IRAF had more frequently AF duration <1 month, a longer P-wave duration, and a longer mid coronary sinus AF cycle length. Multivariate regression analysis revealed coronary sinus AF cycle length ( beta = 0.186, P=0.049), which was closely correlated with conduction time along the coronary sinus (R = 0.716, P = 0.003) to be independently associated with IRAF While early AF recurrence rate (within the first 5 days) following the procedure was higher in the IRAF group (53 vs 18%, P = 0.02), outcome was not different between the two groups thereafter. Conclusions: (1) IRAF is common in patients undergoing PV isolotion for AF, (2) is initiated by premature atrial beats with short coupling intervals, and (3) seems to be associated with conduction disturbances along the coronary sinus. It reflects susceptibility of arrhythmia recurrence within the first 5 days after the procedure, but not thereafter.
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| 4. |
- Höijer, Carl Johan, et al.
(författare)
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Single chamber atrial pacing: A realistic option in sinus node disease: A long-term follow-up study of 213 patients
- 2007
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 30:6, s. 740-747
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Tidskriftsartikel (refereegranskat)abstract
- Background: Despite several decades of experience with atrial pacing, many centers do not apply this mode to any greater extent, mainly because of concerns for the development of future atrioventricular (AV) block or atrial fibrillation. Recent studies have emphasized possible negative effects of right ventricular stimulation, even when AV-synchrony is preserved, and have thus given rise to renewed interest in single chamber atrial pacing for sinus node disease. Methods: This study presents the results of up to 19 years' follow-up of 213 patients with sinus node disease treated with atrial pacing with respect to survival and causes of death, development of atrial fibrillation and AV block, and total mode survival. Patients were divided into two groups: with or without associated atrial tachyarrhythmias at the time of implant. Results are given for all patients and for the two groups separately. Results: The mean follow-up time was 10.1 years. The survival of the entire group was lower after 10 years than that of an age and gender-matched general Swedish population. This was caused by patients with the brady-tachy syndrome (BT) having a significantly higher mortality rate than controls, whereas those with bradycardia only (B) had survival comparable to the general population. Permanent atrial fibrillation (AF) developed in 20% of patients and was significantly more common in patients with BT. The majority of patients with AF (78%) no longer needed any pacing, i.e., did not require ventricular stimulation due to slow ventricular rate. The annual incidence of high grade AV block was 1.8%. If patients with preexisting bundle branch block were excluded, the incidence was 1.6%. No fatal episode of AV block was seen. The overall mode survival at the end of follow-up was 75%, with 155 patients still with atrial pacemakers. Conclusion: Atrial pacing is a safe and reliable mode of pacing in patients with sinus node disease, even in the very long-term.
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| 5. |
- Milasinovic, G, et al.
(författare)
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Reduction of RV pacing by continuous optimization of the AV interval
- 2006
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 29:4, s. 406-412
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Tidskriftsartikel (refereegranskat)abstract
- Background: In patients requiring permanent pacing, preservation of intrinsic ventricular activation is preferred whenever possible. The Search AV+ (SAV+) algorithm in Medtronic EnPulse(TM) dual-chamber pacemakers can increase atrioventricular (AV) intervals to 320 ms in patients with intact or intermittent AV conduction. This prospective, multicenter study compared the percentage of ventricular pacing with and without AV interval extension. Methods: Among 197 patients enrolled in the study, the percentage of ventricular-paced beats was evaluated via device diagnostics at the 1-month follow-up. Patient cohorts were defined by clinician assessment of conduction via a 1:1 AV conduction test at the 2-week follow-up. The observed percentage of ventricular pacing with SAV + ON and the predicted percentage of ventricular pacing with SAV + OFF were determined from the SAV + histogram data for the period between the 2-week and 1-month follow-up visits. Results: Of 197 patients, 110 (55.8%) had intact 1:1 AV conduction, of which 109 had 1-month data. SAV + remained ON in 991109 patients; 10 patients had intrinsic A-V conduction intervals beyond SAV + nominal and therefore SAV + disabled. The mean percentage of ventricular pacing in the 109 patients was SAV+ ON = 23.1% (median 3.7%) versus SAV + OFF = 97.2% (median 99.7%). In 87 patients without 1:1 AV conduction, SAV + was programmed OFF in 6, automatically disabled in 52, and remained ON in 29. In 8 of these patients, 80-100% reduction in ventricular pacing was observed with SAV + ON. Conclusion: The Search AV+ algorithm in the EnPulse pacemaker effectively promotes intrinsic ventricular activation and substantially reduces unnecessary ventricular pacing.
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| 6. |
- Padeletti, Luigi, et al.
(författare)
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Duration of P-wave is associated with atrial fibrillation hospitalizations in patients with atrial fibrillation and paced for bradycardia
- 2007
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 30:8, s. 961-969
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Tidskriftsartikel (refereegranskat)abstract
- Background: A trial fibrillation (AF) is a common problem in pacemaker patients. We conducted a prospective observational study in patients paced for bradycardia with associated paroxysmal or persistent AF, to determine whether P-wave duration may stratify patients at higher risk for AF recurrences and AF-related hospitalizations. The patients were evaluated for the prevalence, cause, and predictors of hospitalization. Methods: We studied 660 consecutive patients (50% male, 72 +/- 9 years) who received a dual-chamber pacemaker. Median value of baseline P-wave duration was equal to 100 ms (25%-75% quartile range equal to 80-120 ms). We used this cut-off to divide the patients into group A (P <= 100 ms), composed of 385 (58.3%) patients, and group B (P > 100 ms), composed of 275 (41.7%) patients. Results: In a median follow-up of 19 months, 173 patients were hospitalized for all causes, 130 for cardiovascular causes, and 85 for AF-related hospitalizations. Multivariate logistic analysis showed that P-wave duration > 100 ms identified patients at higher risk (OR = 1.6, 95% confidence interval (1.1-2.8), P = 0.044) for AF-related hospitalizations. Patients in group B (P > 100 ms) more frequently suffered AF-related hospitalizations (16.4% vs 10.4%, P = 0.02) and underwent more frequent cardioversions (14.5% vs 9.1%, P = 0.029) compared with group A (P < 100 ms). Conclusions: P-wave duration may define the risk of persistent AFrequiring cardioversion or AF-related hospitalization in patients with a pacemaker for bradycardia with associated paroxysmal or persistent AF.
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| 7. |
- Puererfellner, Helmut, et al.
(författare)
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Comparison of two strategies to reduce ventricular pacing in pacemaker patients
- 2008
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 31:2, s. 167-176
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Tidskriftsartikel (refereegranskat)abstract
- Background: Managed Ventricular Pacing (MVP) and Search AV+ (SAV+) are two pacing algorithms designed to reduce ventricular pacing, MVP promotes conduction by operating in AAI/R mode with backup ventricular pacing during atrioventricular block (AVB). SAV+ operates in DDD/R mode with a nominal AV extension of 290 ms during atrial sensing and 320 ms during atrial pacing. The reduction in ventricular pacing was compared with these two algorithms in pacemaker patients. Methods: The EnRhythm and EnPulse clinical studies assessed the Percentage of ventricular pacing (% VP) after 1 month. Each patient's AVB status was assigned using the following hierarchical categories: persistent third-degree AVB (p3AVB), episodic third-degree AVB (e3AVB), second-degree AVB (2AVB), first-degree AVB (1AVB), and no AVB (nAVB). The% VP was tabulated for each AVB status category. Results: Data were available from 322 patients of whom 129 received DDD(R) pacing with the MVP algorithm activated and 193 patients with DDD(R) pacing and the SAV+ function activated, each for a month period. MVP resulted in a significantly lower median % VP than SAV+ in all AVB categories except for p3AVB: nAVB (0.3 vs 2.9, P < 0.0001), 1AVB (0.9% vs 80.6%. P < 0.0001), 2AVB (37.6 vs 99.3. P < 0.002), e3AVB (1.2 vs 42.2, P = 0.02), p3AVB (98.9 vs 100, P = 1.00). Conclusion: MVP resulted in a greater reduction in% VP than SAV+ across all patient groups except persistent third-degree AV block. The greatest reduction in%VP was observed in patients with mildly impaired AV conduction.
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| 8. |
- Yuan, S, et al.
(författare)
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Clinical application of a microcomputer system for analysis of monophasic action potentials
- 1996
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Ingår i: PACE. - : Wiley. - 0147-8389. ; 19:3, s. 297-308
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Tidskriftsartikel (refereegranskat)abstract
- UNLABELLED: Computerized analysis of monophasic action potentials (MAPs) has rarely been reported in clinical setting. We developed a computer system featuring on-line acquisition and user-monitored automatic measurement of multichannel MAPs with the capability of manual corrections. This system has been used in 34 patients in whom two-channel MAPs and 1-lead ECG were digitized during sinus rhythm, pacing, and programmed stimulation (PS). In total, 41, 413 MAPs in 212 data files were measured. The correct determination rate was 100% for MAP onset and plateau, 99.78% (95.76% during PS) for MAP baseline, and 99.96% (54.29% during PS) for QRS onset. The comparison between the computerized and manual measurements in 292 MAPs showed that the former highly agreed with the latter, with the limits of agreement, defined as mean difference +/- 2 SD, being from -4.8-4.9 ms for activation time and from -4.1-6.0 ms for MAP duration measurements. Using this system, two-channel MAPs of more than 300 consecutive beats can be measured in a few minutes, which made it possible to determine the steady state of MAP duration individually, and evaluate the MAP changes during intervention in detail. The clinical routine procedure for testing the effective refractory period and several new MAP parameters were also evaluated using this system.CONCLUSION: The MAP measurement using this computer system is reliable, rapid and accurate; it can therefore replace the manual method and provide more useful information for clinical research.
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| 9. |
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| 10. |
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| 11. |
- Blomström-Lundqvist, C, et al.
(författare)
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Incessant ventricular tachycardia with a right bundle-branch block pattern and left axis deviation abolished by catheter manipulation
- 1990
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 13:1, s. 11-16
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Tidskriftsartikel (refereegranskat)abstract
- A 22-year-old man underwent electrophysiological evaluation for incessant wide QRS complex tachycardia with a pattern of right bundle-branch block and left axis deviation. The right and left ventricles were enlarged and hypokinetic consistent with dilated cardiomyopathy. Ventricular tachycardia was diagnosed by demonstrating capture and fusion beats, atrioventricular dissociation, and His potential activation that began after the onset of each QRS complex. Atrial extrastimuli and rapid atrial pacing failed to terminate the tachycardia and, although ventricular stimulation was successful, the tachycardia spontaneously restarted after one or two sinus beats. The tachycardia was unexpectedly abolished during catheter manipulation in the left ventricle and has not recurred during three-years of follow-up. The picture of a cardiomyopathy resolved. The ease with which the tachycardia was abolished by catheter manipulation implicate a therapeutic potential for catheter ablation of this type of tachycardia.
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| 12. |
- Blomström-Lundqvist, Carina
(författare)
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The safety of reusing ablation catheters with temperature control and the need for a validation protocol and guidelines for reprocessing
- 1998
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 21:12, s. 2563-2570
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate the safety of reusing ablation catheters with temperature control, which has not previously been reported. A review of previously conducted studies on the feasibility of reusing electrode catheters is also presented. From September 1994 to December 1997, 74 deflectable ablation catheters with temperature control (Cordis-Websters and Osypkas) were used during mean 7.6 +/- 8.0 ablation sessions. The catheter tests included visual inspection for surface defects using a magnification glass, impedance measurements, evaluation of the catheter deflection capability, and the integrity of the thermistor and thermocouple. The catheters were sterilized by Sterrad after each use. A total of 41 catheters were rejected after an average 9.1 +/- 8.8 uses (range 1-31). The main reasons for rejection were inaccurate temperature measurements by the thermistor or thermocouple (19%), breakage of or defect in the internal pulling wire (12%), loss or disturbance of electrogram (9%), and loss of deflection capability (8%). The reuse of the catheters has not resulted in any major catheter failures or any major adverse clinical complications. There were no local or systemic infections. It can be concluded that these types of ablation catheters will sustain repeated uses and resterilizations without untoward harm to the patient provided that a thorough validation protocol and guidelines for quality control and rejection of catheters are used. There seems to be no rational for setting a limit for the number of reuses, since most failures occurred at any time of reuse.
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| 13. |
- Blomström-Lundqvist, C, et al.
(författare)
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Transesophageal versus intracardiac atrial stimulation in assessing electrophysiologic parameters of the sinus and AV nodes and of the atrial myocardium
- 1987
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 10:5, s. 1081-1095
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Tidskriftsartikel (refereegranskat)abstract
- Electrophysiological porameters of the sinus and AV nodes and of the atrial myocardium were assessed with both transesophageal atrial stimulation (TAS) and intracardiac atrial stimulation (ICS) in the same patient during the same study. The study group was comprised of nine men and seven women, aged 45 to 79 years, referred for the evaluation of syncope of possible arrhythmogenic origin. Twelve patients were included for analysis. Autonomic inhibition (AI) was obtained in five patients. The most striking result was the significantly longer AERP with TAS (mean 286 ± 9 ms) than with ICS (mean 244 ± 12 ms; p < 0.02). After AI, the AERP was even more prolonged with TAS (mean 332 ± 20 ms) than with ICS (mean 237 ± 8 ms; p < 0.01). Intraatrial and AV nodal conduction times assessed at multiple paced cycle lengths were significantly shorter with TAS than with ICS. There was no difference between TAS and ICS with regard to AVERP, Wenckebach periodicity and H-V intervals. Although a tendency towards shorter sinus node recovery time (SNRT) and sinoatrial conduction time (SACT) was observed with TAS, the difference was not statistically significant. Possible mechanisms of the differences are discussed. It seemed clear that the site of origin of an atrial impulse can have definite effects upon excitability and conduction properties of atrial and AV nodal fibers. Enhanced sympathetic activity during TAS was also suggested. The electrophysiological properties inherent in the TAS technique warrant further elucidation.
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| 14. |
- Emilsson, Kent, 1963-, et al.
(författare)
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An unusual cause of high threshold values at pacemaker implantation
- 1997
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Ingår i: Pacing and Clinical Electrophysiology. - : John Wiley & Sons. - 0147-8389 .- 1540-8159. ; 20:Part: 1, s. 366-7
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Tidskriftsartikel (refereegranskat)abstract
- An 81-year old man with third-degree AV block and weakness underwent an unsuccessful attempt to DDD pacemaker implant caused by hypothyroidism. Administration of thyroxin until he was euthyroid permitted implantation with normal stimulation thresholds.
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| 15. |
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| 16. |
- Gottfridsson, Christer, 1958, et al.
(författare)
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Acute evaluation of transthoracic impedance vectors using ICD leads.
- 2009
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Ingår i: Pacing and clinical electrophysiology : PACE. - : Wiley. - 1540-8159 .- 0147-8389. ; 32:6, s. 762-71
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Minute ventilation (MV) has been proven to be very useful in rate responsive pacing. The aim of this study was to evaluate the feasibility of using implantable cardioverter-defibrillator (ICD) leads as part of the MV detection system. METHODS: At implant in 10 patients, the transthoracic impedance was measured from tripolar ICD, tetrapolar ICD, and atrial lead vectors during normal, deep, and shallow voluntary respiration. MV and respiration rate (RespR) were simultaneously measured through a facemask with a pneumotachometer (Korr), and the correlations with impedance-based measurements were calculated. Air sensitivity was the change in impedance per change in respiratory tidal volume, ohms (Omega)/liter (L), and the signal-to-noise ratio (SNR) was the ratio of the respiratory and cardiac contraction components. RESULTS: The air sensitivity and SNR in tripolar ICD vector were 2.70 +/- 2.73 ohm/L and 2.19 +/- 1.31, respectively, and were not different from tetrapolar. The difference in RespR between tripolar ICD and Korr was 0.2 +/- 1.91 breaths/minute. The regressed correlation coefficient between impedance MV and Korr MV was 0.86 +/- 0.07 in tripolar ICD. CONCLUSIONS: The air sensitivity and SNR in tripolar and tetrapolar ICD lead vectors did not differ significantly and were in the range of the values in pacemaker leads currently used as MV sensors. The good correlations between impedance-based and Korr-based RespR and MV measurements imply that ICD leads may be used in MV sensor systems.
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| 17. |
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| 18. |
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| 19. |
- Jensen, Steen, et al.
(författare)
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Syncope and wide QRS tachycardia.
- 2005
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Ingår i: Pacing Clin Electrophysiol. - : Wiley. - 0147-8389. ; 28:7, s. 708-9
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Tidskriftsartikel (refereegranskat)
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| 20. |
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| 21. |
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| 22. |
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| 23. |
- Kesek, Milos, et al.
(författare)
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U22, a protocol to quantify symptoms associated with supraventricular tachycardia.
- 2009
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 32:S1, s. S105-S108
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The main indication for ablation of supraventricular tachyarrhythmias (SVTA) is symptomatic relief. Specific paroxysmal symptoms cannot be quantified with general measures of quality of life, such as with the SF-36 questionnaire. U22 is a new protocol which measures the effects of arrhythmia on well-being, the intensity of discomfort during an episode, the type and temporal characteristics of dominant symptoms, and the duration and frequency of episodes. Discrete 0-10 scales are used. Unlike SF-36, U22 can be used in individual patients. METHODS: U22 and SF-36 protocols were used in the symptomatic evaluation of 88 patients (mean age = 49.6 +/- 16.4 years; 43 men), who underwent catheter ablation of SVTA. Results: The U22 scores (SD) for (a) well-being (10 being best), (b) effects of arrhythmia on well-being (10 being worst), and (c) discomfort during arrhythmia (10 being worst) were 5.6 (2.7), 7.5 (2.8), and 8.0 (2.4), respectively. For comparison, the physical and mental component summaries of SF-36 were 45.3 (11.0) and 45.2 (12.1), respectively, slightly lower than the expected normal of 50. The intensity of dominant symptom scored by U22 was 9.7 (1.2), 10 being worst. In 29% of patients > or =4 symptoms were equally dominant. Multiple dominant symptoms in U22 were associated with a low general well-being in SF-36. CONCLUSION: We found U22 useful to quantify symptoms associated with SVTA.
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| 24. |
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| 25. |
- LINDE, C, et al.
(författare)
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Pacing in dilated cardiomyopathy
- 1995
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Ingår i: Pacing and clinical electrophysiology : PACE. - : Wiley. - 0147-8389 .- 1540-8159. ; 18:7, s. 1341-1345
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 26. |
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| 27. |
- Michaëlsson, Magnus, et al.
(författare)
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Natural history of congenital complete atrioventricular block
- 1997
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 20:8 Pt 2, s. 2098-2101
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Tidskriftsartikel (refereegranskat)abstract
- An update of studies on the natural history of congenital complete AV block is presented. A risk for heart failure, syncope, and sudden death is present at any age including fetal life. Unfavorable prognostic signs in utero are low and decreasing ventricular rate (VR), hydrops, AV valve regurgitation, and low aortic flow velocity. Indications for pacing in infancy are congestive heart failure, ventricular rate < 55 beats/min in isolated block and < 65 beats/min with associated disease, prolonged OTc, syncope attacks, frequent ventricular ectopic beats, and alternating ventricular pacemakers. Indications for immediate pacing in childhood and adult life are syncope, presyncope, VR rates lower than median for age, periods of junctional exit block, prolongation of QTc and mitral regurgitation, and change of ventricular pacemaker. Pacing is recommended to all patients older than 15 years.
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| 28. |
- Nowinski, K., et al.
(författare)
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Pacing-induced electrophysiological remodeling in hypertrophic obstructive cardiomyopathy--observations on cardiac memory
- 2005
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Ingår i: Pacing Clin Electrophysiol. - : Wiley. - 0147-8389 .- 1540-8159. ; 28:6, s. 561-7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Hypertrophic cardiomyopathy carries an increased risk for sudden cardiac death. While pacing therapy reduces the left ventricular outflow tract gradient and improves symptoms in a subgroup of hypertrophic obstructive cardiomyopathy (HOCM) patients, its electrophysiological consequences are unknown and were therefore assessed in this prospective study. METHODS AND RESULTS: Fifteen consecutive HOCM patients were studied and compared with 14 patients without HOCM paced because of sinus bradycardia. ECG intervals were measured before pacemaker implantation and after > or =3 months of DDD pacing in HOCM patients and > or =5 weeks in controls. Both groups showed similar ECG signs of cardiac memory development. In HOCM patients, with baseline QTc 447 +/- 33 ms, cardiac memory development was not associated with any significant changes in ECG intervals. In contrast, baseline repolarization in control patients was significantly prolonged by 6% (QTc 429 +/- 33 vs 454 +/- 46 ms; P < 0.05). Furthermore, in HOCM patients repolarization was 7% shorter during DDD pacing compared to sinus rhythm (JTc 329 +/- 25 vs 353 +/- 21 ms; P < 0.05), despite a significantly prolonged ventricular activation time (QRS duration 155 +/- 16 vs 91 +/- 9 ms; P < 0.01). CONCLUSIONS: Importantly, the development of cardiac memory-induced different repolarization responses depending on baseline structure and electrophysiology. In HOCM patients repolarization was shorter during right ventricular apical pacing than during normal activation despite prolonged activation time.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Sperzel, Johannes, et al.
(författare)
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Clinical performance of a ventricular automatic capture verification algorithm.
- 2005
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Ingår i: Pacing and clinical electrophysiology : PACE. - : Wiley. - 0147-8389 .- 1540-8159. ; 28:9, s. 933-7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: This study was conducted to evaluate the clinical performance of the ventricular automatic capture feature as implemented in the Insignia I Ultra pacemaker system (Guidant) utilizing a variety of ventricular leads. Currently, the optimal programming of the pacemaker output considers both pacemaker efficiency (prolonging battery longevity) and patient safety (adequate safety margin). The ability of a pacemaker to automatically adjust the ventricular output above the pacing threshold while maintaining the appropriate safety margin has been explored since the early 1970s and is only available today in conjunction with a specific low polarization lead system. METHODS: One hundred and five patients were enrolled from 17 European centers utilizing 31 different types of ventricular leads were followed through their 3-month follow-up visit. There were no restrictions on the type of ventricular leads used. RESULTS: The average mean difference between the commanded autothreshold test (0.652 + 0.335 V) and the manual threshold test (0.651 + 0.335 V) was 0.001 + 0.49 (P < 0.0001). The average mean difference between the ambulatory autothreshold test (0.696 + 0.322 V) and the commanded autothreshold test (0.682 + 0.315 V) was 0.002 + 0.74 (P < 0.0001). Holter recordings confirmed that there were no loss of capture incidences without a backup pulse being delivered. In addition, the mean number of backup pulses delivered in a 24-hour period was less than 0.1% of the total number of paced beats. CONCLUSIONS: This study provided that the automatic capture feature while using a variety of leads accurately determines the ventricular stimulation threshold and safely delivers a backup pulse when required.
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| 33. |
- Sperzel, Johannes, et al.
(författare)
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Performance evaluation of a right atrial automatic capture verification algorithm using two different sensing configurations.
- 2009
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Ingår i: Pacing and clinical electrophysiology : PACE. - : Wiley. - 1540-8159 .- 0147-8389. ; 32:5, s. 579-87
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: This acute data collection study evaluated the performance of a right atrial (RA) automatic capture verification (ACV) algorithm based on evoked response sensing from two electrode configurations during independent unipolar pacing. METHODS: RA automatic threshold tests were conducted. Evoked response signals were simultaneously recorded between the RA(Ring) electrode and an empty pacemaker housing electrode (RA(Ring)-->Can) and the electrically isolated Indifferent header electrode (RA(Ring)-->Ind). The atrial evoked response (AER) and the performance of the ACV algorithm were evaluated off-line using each sensing configuration. An accurate threshold measurement was defined as within 0.2 V of the unipolar threshold measured manually. Threshold tests were designed to fail for small AER (< 0.35 mV) or insufficient signal-to-artifact ratio (SAR < 2). Manual threshold measurements were obtained during RA unipolar and bipolar pacing and compared across device indications. RESULTS: Data were collected from 38 patients with RA bipolar leads from four manufacturers. AER signals were analyzed from 34 patients who were indicated for a pacemaker (five), implantable cardioverter-defibrillator (11), or cardiac resynchronization therapy pacemaker (six) or defibrillator (12). The minimum AER amplitude was larger (P < 0.0001) when recorded from RA(Ring)-->Can (1.6+/-0.9 mV) than from RA(Ring)-->Ind (1.3+/-0.8 mV). The algorithm successfully measured the pacing threshold in 96.8% and 91.0% of tests for RA(Ring)-->Can and RA(Ring)-->Ind, respectively. No statistical difference between the unipolar and bipolar pacing threshold was observed. CONCLUSIONS: The RA(Ring)-->Can AER sensing configuration may provide a means of implementing an independent pacing/sensing method for ACV in the RA. RA bipolar pacing therapy based on measured RA unipolar pacing thresholds may be feasible.
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| 35. |
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| 36. |
- Tesselaar, Erik, et al.
(författare)
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Effect of Cardiac Resynchronization Therapy on Endothelium-Dependent Vasodilatation in the Cutaneous Microvasculature
- 2012
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley-Blackwell. - 0147-8389 .- 1540-8159. ; 35:4, s. 377-384
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Cardiac resynchronization therapy (CRT) improves hemodynamic parameters, exercise capacity, symptoms, functional status, and prognosis among patients with chronic heart failure (CHF). The role of the vascular endothelium in these improvements is largely unknown. In this study, we aimed to investigate whether the endothelium-dependent reactivity of the peripheral microcirculation improves in CHF patients during the first 2 months of CRT. less thanbrgreater than less thanbrgreater thanMethods: We used local heating and iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) to measure endothelial function and smooth muscle function in the cutaneous microvasculature of 11 CHF patients before and 2 months after CRT. less thanbrgreater than less thanbrgreater thanResults: We found that the perfusion response in the skin to local heating was increased 2 months postCRT compared with baseline, both in terms of maximum perfusion (baseline: 113 [90-137] vs 2-months post-CRT: 137 [98-175], P = 0.037) and area under curve (baseline: 1,601 [935-2,268] vs 2-months CRT: 2,205 [1,654-2,757], P = 0.047). Also, the perfusion response to iontophoresis of ACh was improved (Emax: 23.9 [20.6-26.2] vs at 2-months CRT: 31.2 [29.3-33.4], P = 0.005). No difference was found between the responses to SNP before and after CRT. less thanbrgreater than less thanbrgreater thanConclusion: These results show that CRT improves endothelium-dependent vasodilatory capacity in the peripheral microcirculation within 2 months of therapy. The improvement in functional capacity that is seen in patients treated with CRT may, therefore, be in part mediated by an improvement of endothelium-dependent vasodilatory capacity.
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| 37. |
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| 38. |
- Walfridsson, Håkan, et al.
(författare)
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Sensing of atrial fibrillation by a dual chamber pacemaker : How should atrial sensing be programmed to ensure adequate mode shifting?
- 2000
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Ingår i: Pacing and Clinical Electrophysiology. - : John Wiley & Sons. - 0147-8389 .- 1540-8159. ; 23:7, s. 1089-1093
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Tidskriftsartikel (refereegranskat)abstract
- Patients with atrial fibrillation and a DDDR pacemaker were studied to assess mode switching at different atrial sensitivity settings. Thirty-one patients were investigated 7 ± 9 months after pacemaker implantation and 20 of those patients were rein-vestigated 23 ± 9 months after implant. Adequate mods switching was evaluated by stepwise programming the atrial sensitivity setting from maximal to minimal in the bipolar mode. Adequate mode switching was observed in all 31 patients during the first evaluation. The lowermost sensitivity average allowing for mode switching was 1.1 ± 0.7 mV (range 0.3–4.0 mV). A total of 22 (71%) patients demonstrated intermittent mode shifting at sensitivity settings above the atrial sensing threshold. In six (19%) patients, the adequate sensitivity threshold ranged from 0.3 to 0.5 mV, which did not allow for a two-fold sensitivity safety margin. During the second evaluation, adequate mode switching was achieved in all 20 patients, the lowermost sensitivity average allowing for mode switching being 1.1 ± 0.7 mV (range 0.3–2.0 mV). A total of 16 (80%) patients showed intermittent mode shifting at a sensitivity setting above the atrial sensing threshold. In five (25%) patients, the sensitivity threshold ranged from 0.3 to 0.5 mV, which did not allow for a two-fold sensitivity safety margin. Adequate mode switching was achieved in 31 of 31 patients in response to atrial fibrillation on one occasion and in all 20 patients on two occasions. It was necessary to program the atrial sensitivity to the highest possible level (0.3 mV) to ensured adequate mode switching in all cases.
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| 39. |
- Walfridsson, Ulla, et al.
(författare)
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The impact of supraventricular tachycardias on driving ability in patients referred for radiofrequency catheter ablation
- 2005
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 28:3, s. 191-195
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The aim of the present study was to evaluate the occurrence of arrhythmia-related symptoms in patients with supraventricular tachycardia (SVT) referred for radiofrequency catheter ablation (RF ablation) with special focus on driving ability. Methods and Results: Of the 301 patients referred for RF ablation between November 1998 and December 2000 due to SVT 226 were active drivers. The present study is an interview study with structured questions. Hemodynamic symptoms were frequently encountered during tachycardia. The symptoms occurred irrespective of driving. In the 226 active drivers, fatigue was reported in 77%, dizziness in 47%, breaking into a cold sweat in 52%, near-syncope in 50%, and syncope in 14%. Women experienced all symptoms more frequently than men: fatigue (P < 0.05), dizziness (P < 0.01), cold sweat (P < 0.05), near-syncope (P < 0.001), and syncope (P < 0.01). Fifty-seven percent of the patients had experienced tachycardia while driving, and 42% of those patients had to stop because of it. Twenty-four of all patients considered their tachycardia as an obstacle to driving. There was a significant correlation (P < 0.001) between having experienced near-syncope and considering the risk for tachycardia as an obstacle. Conclusions: SVT frequently occurs during driving and is often associated with hemodynamic symptoms including near-syncope and syncope. Women reported tachycardia-related hemodynamic symptoms more often than men. There is a correlation between having experienced near-syncope and considering tachycardia as an obstacle to driving. The risk for serious tachycardia-related symptoms should be considered, especially in occupational drivers.
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| 40. |
- Walfridsson, Ulla, et al.
(författare)
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Wolff-Parkinson-White Syndrome and Atrioventricular Nodal Re-Entry Tachycardia in a Swedish Population: Consequences on Health-Related Quality of Life
- 2009
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 32:10, s. 1299-1306
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Tidskriftsartikel (refereegranskat)abstract
- Background: Living with paroxysmal supraventricular tachycardia affects a patient's whole life situation, but few studies have addressed health-related quality of life (HRQOL) aspects in these patients. The aim was therefore to describe HRQOL in patients with atrioventricular nodal re-entry tachycardia (AVNRT) or Wolff-Parkinson-White (WPW) syndrome, referred for radiofrequency ablation (RF-ablation), compared to age- and gender-matched Swedish reference groups. Methods: HRQOL was assessed with SF-36 and EuroQol (EQ-5D and EQ-VAS) and the patients were asked disease-specific questions. Results: The 97 patients with AVNRT [53 ± 16 years of age/65 women] and 79 patients with WPW [42 ± 15 years of age/26 women] exhibited significantly lower HRQOL scores in SF-36 in the same seven of the eight scales: Physical functioning (PF), role-physical (RP), social functioning (SF), role-emotional (RE), general health (GH), vitality (VT), and mental health (MH) while there was no difference in bodily pain (BP) compared to their respective age- and gender matched Swedish reference group. HRQOL scores were lower for patients with AVNRT compared to WPW in the areas of PF (P < 0.001), BP (P < 0.05), and GH (P < 0.01) in SF-36, and the same was found in EQ-VAS (64.8 vs. 71.2, P < 0.05). Occurrence of episodes of tachycardia more often than once a month compared to less frequently than once a month was associated with significantly lower HRQOL in all eight scales in SF-36 (GH, RE, MH: P < 0.01 and PF, RP, BP, VT, SF: P < 0.001) and EQ-5D index (P < 0.001) and EQ-VAS (P < 0.05) Arrhythmia duration longer than one hour compared to patients with shorter duration of the tachycardia-affected GH in SF-36 negatively (P < 0.05). Patients who experienced symptoms not only during activity but also at rest scored lower in SF-36 GH (P < 0.01) and SF (P < 0.05). Conclusion: Measuring HRQOL in patients with WPW or AVNRT is an important way to evaluate and describe these patients' life situation. These conditions were found to have a pronounced negative impact on HRQOL. The frequency of arrhythmia occurrence is one important factor to consider when setting priorities for treatment with RF-ablation.
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| 41. |
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| 43. |
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| 44. |
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| 45. |
- Björkenheim, Anna, 1980-, et al.
(författare)
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Rhythm Control and its Relation to Symptoms During the First Two Years After Radiofrequency Ablation for Atrial Fibrillation
- 2016
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Ingår i: Pacing and Clinical Electrophysiology. - Hoboken, USA : Wiley-Blackwell Publishing Inc.. - 0147-8389 .- 1540-8159. ; 39:9, s. 914-925
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate rhythm control up to two years after AF ablation and its relation to reported symptoms.Background: The implantable loop recorder (ILR) continuously records the ECG, has an automatic AF detection algorithm and a possibility for patients to activate an ECG recording during symptoms.Methods: Fifty-seven patients (mean age 57±9 years, 60% male, 88% paroxysmal AF) underwent AF ablation following ILR implantation. Device data were downloaded at the ablation and three, six, 12, 18 and 24 months after ablation.Results: Fifty-four patients completed the two-year follow-up. Thirteen (24%) patients had no AF episodes detected by ILR during follow-up. Ten of 41 patients (24%) with AF recurrence were only detected by ILR and AF recurrences were detected earlier by ILR (P<0.001). The median AF burden in patients with AF recurrence was 5.7% (IQR 0.4-14.4) and was even lower in patients with AF only detected by ILR (P = 0.001). Forty-eight % of the patients indicated symptoms via the patient activator but 33% of those recordings were not due to AF. Early AF recurrence (within 3 months) was highly associated with later AF recurrence (P<0.001). AF burden >0.5% and longest >6h before the ablation were independent predictors of AF recurrence during intermittent but not continuous monitoring.Conclusions: After AF ablation, the AF burden was low throughout the 24 months follow-up. Nevertheless, symptoms were commonly indicated but one third of patient activated recordings did not show AF. Continuous monitoring was superior to intermittent follow-up in detecting AF episodes and assessing the AF burden.Clinical trial registration: URL: http://clinicaltrials.gov. Unique Identifier: NCT00697359.
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| 46. |
- Candinas, R, et al.
(författare)
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Impact of fusion avoidance on performance of the automatic threshold tracking feature in dual chamber pacemakers: A multicenter prospective randomized study
- 2002
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 25:11, s. 1540-1545
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Tidskriftsartikel (refereegranskat)abstract
- The Autocapture algorithm enables automatic capture verification on a beat-by-beat basis by recognizing the evoked response signal following each pacemaker stimulus. The algorithm intends to increase patient safety while decreasing energy consumption. However, the occurrence of fusion beats, particularly during dual chamber pacing, may limit the energy saving effect of Autocapture. The aim of this multicenter, prospective, randomized study was to evaluate the impact of the Fusion Avoidance (FA) algorithm on the incidence of fusion beats. Thirty-eight patients (mean age 69 +/- 13 years) with intrinsic AV conduction who were implanted with an Affinity DR were studied. After programming a PV/AV delay of 120/190 ms, patients were randomized to FA On or Off. Each group was further randomized with respect to activation of the AutoIntrinsic Conduction Search (AICS) algorithm. The total number of beats, ventricular paced beats, fusion beats, backup pulses, and threshold searches were analyzed from 24-hour Holter recordings. The number of total beats was comparable in both FA groups. The number of total ventricular paced beats, fusion beats, backup pulses, and threshold searches were significantly reduced in the FA On group (% reduction: 68% P < 0.001, 75% P < 0.01, 95% P < 0.01, and 94% P < 0.05, respectively). The number of ventricular paced beats with full capture was significantly reduced when AICS was activated (P < 0.05). In conclusion, the FA algorithm substantially reduces the amount of ventricular paced beats, fusion beats, unnecessary backup pulses and threshold searches, and therefore, provides added benefits in energy saving obtained by Autocapture.
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| 47. |
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| 48. |
- Farouq, Maiwand, et al.
(författare)
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Successful percutaneous extraction of malpositioned pacemaker lead in the left ventricle after proper dabigatran treatment
- 2022
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Ingår i: PACE - Pacing and Clinical Electrophysiology. - : Wiley. - 1540-8159 .- 0147-8389. ; 45:9, s. 1101-1105
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Tidskriftsartikel (refereegranskat)abstract
- Malpositioned pacemaker lead in the left ventricle (LV) is a rare procedural complication, which causes a special risk of thromboembolic events. Hence, prompt identification and early management of misplaced leads inside the LV is critical. Herein, we present a case of malpositioned pacemaker lead with transient ischemic attacks after the pacemaker implantation. The misplaced ventricular lead was discovered during regular echocardiography. Both leads were extracted percutaneously after dabigatran treatment. To our knowledge, this is the first report of uncomplicated percutaneous extraction of an inadvertently placed LV lead after dabigatran treatment. No neurologic events during a follow-up of 4 years.
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