Repolarization changes underlying long-term cardiac memory due to right ventricular pacing: noninvasive mapping with electrocardiographic imaging.
نویسندگان
چکیده
BACKGROUND Cardiac memory refers to the observation that altered cardiac electrical activation results in repolarization changes that persist after the restoration of a normal activation pattern. Animal studies, however, have yielded disparate conclusions, both regarding the spatial pattern of repolarization changes in cardiac memory and the underlying mechanisms. The present study was undertaken to produce 3-dimensional images of the repolarization changes underlying long-term cardiac memory in humans. METHODS AND RESULTS Nine adult subjects with structurally normal hearts and dual-chamber pacemakers were enrolled in the study. Noninvasive electrocardiographic imaging was used before and after 1 month of ventricular pacing to reconstruct epicardial activation and repolarization patterns. Eight subjects exhibited cardiac memory in response to ventricular pacing. In all subjects, ventricular pacing resulted in a prolongation of the activation recovery interval (a surrogate for action potential duration) in the region close to the site of pacemaker-induced activation from 228.4±7.6 ms during sinus rhythm to 328.3±6.2 ms during cardiac memory. As a consequence, increases are observed in both apical-basal and right-left ventricular gradients of repolarization, resulting in a significant increase in the dispersion of repolarization. CONCLUSIONS These results demonstrate that electrical remodeling in response to ventricular pacing in human subjects results in action potential prolongation near the site of abnormal activation and a marked dispersion of repolarization. This dispersion of repolarization is potentially arrhythmogenic and, intriguingly, was less evident during continuous right ventricular pacing, suggesting the novel possibility that continuous right ventricular pacing at least partially suppresses pacemaker-induced cardiac memory.
منابع مشابه
Repolarization Changes Underlying Long-Term Cardiac Memory Due to Right Ventricular Pacing: Noninvasive Mapping with ECGI
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6 List of original papers 7 List of abbreviations 8 Introduction 9 Cardiac cellular electrophysiology 12 Recording cardiac electricity 16 Electrocardiography (ECG) 16 Vectorcardiography (VCG) 16 Pacemaker treatment 20 Sick Sinus Syndrome 21 Hypertrophic Obstructive Cardiomyopathy (HOCM) 21 Wolff-Parkinson-White Syndrome (WPW syndrome) 22 Aims 23 Material and Methods 24 Studies I and II 24 Study...
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عنوان ژورنال:
- Circulation. Arrhythmia and electrophysiology
دوره 5 4 شماره
صفحات -
تاریخ انتشار 2012