Abstract
Title: |
Does
Biventricular Pacing Decrease the Incidence of Microvolt T-Wave Alternans? |
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Presentation
Start: |
Sunday,
Mar 30, 2003, 10:00 AM -11:00 AM |
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Topic: |
Clinical
Electrophysiology--Ventricular Arrhythmias |
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Author
Block: |
Raymond
C. Leung, Sajad
Gulamhusein, Alberta Van Schaik, Katherine Kavanagh, University of Alberta,
Edmonton, AB, Canada |
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Background: Biventricular pacing (BiVP)
improves symptoms and hemodynamics in heart failure patients with ventricular
conduction delay. Controversy exists as to why a significant reduction of
ventricular arrhythmia was observed in patients with BiVP. Presence of
microvolt T-wave alternans (TWA) during rapid atrial pacing is independently
predictive of ventricular arrhythmic events. We hypothesize that BiVP reduces
ventricular arrhythmias by repolarization resynchronization as measured by a
reduction of TWA. Methods: Patients (n=13) with permanent BiVP were
studied. TWA were measured by spectral method using Heartwave system
(Cambridge Heart) at rapid atrial (AAI) and various ventricular (DDD) pacing
modes. TWA were interpreted by standard protocol. Results: Four
patients were excluded due to AV block at <105 bpm. The results of the
remaining 9 patients are shown below. In AAI pacing, 8 of the 9 patients
(89%) have positive TWA. Comparatively, frequency of positive TWA was reduced
to 67% (6/9; RRR=25%; p=0.57) in DDD-RV, 44% (4/9; RRR=50%; p=0.13) in DDD-LV
and 22% (2/9; RRR=75%; p=0.018) in DDD-BiV. Conclusion: BiVP improves
repolarization properties as measured by a reduction of TWA, thus
contributing to the reduction of ventricular arrhythmias through this novel
mechanism.
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