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Author
Block:
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Gioia
Turitto, Seing
Houy, Ravi Gupta, Ronald Pedalino, Nabil El-Sherif, SUNY - Downstate Medical
Center, Brooklyn, NY
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Background: Compared to right ventricular
(RV) pacing, biventricular (BiV) pacing is believed to result in improved
mechanical and electrophysiologic parameters. Tachycardia-dependent T-wave
alternans (TWA) is associated with increased dispersion of ventricular
repolarization and is considered a strong predictor of malignant ventricular
tachyarrhythmias.
Methods: We compared the prevalence of TWA in a group of patients (26
males, 6 females, age: 59+15 years, left ventricular ejection
fraction: 34+14%, with values <35% in 25 patients) during atrial
pacing, atrio-ventricular (AV) pacing from the RV (AV-RV), and AV pacing from
both RV and LV (AV-BiV). The study was conducted during electrophysiology
evaluation and/or following device implantation. Pacing rate was 110/min and
pacing modes were performed in random order for 10 min each. Criteria for
positive TWA were voltage >1.9 μV with ratio (k) >3 for >1 min in >1
orthogonal lead and/or >2 precordial leads.
Results: TWA was induced by atrial pacing in 31% of patients, by AV-RV
pacing in 81% of patients, and by AV-BiV pacing in 40% of patients. There was
a statistically significant increase of all TWA parameters between atrial
pacing and AV-RV pacing (p<0.001) and between AV-BiV and AV-RV pacing
(p<0.01). However, there was no statistically significant difference
between AP and AV-BiV pacing modes.
Conclusions: RV pacing, even for a short duration, is associated with
markers of increased ventricular electrical vulnerability, which are
significantly ameliorated by BiV pacing.
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