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The effect of procainamide on T wave alternans
N G Kavesh1, S R Shorofsky, S E Sarang
1St. Joseph's Hospital, Syracuse, New York, USA.
Journal of Cardiovascular Electrophysiology
|June 4, 1999
Summary
Procainamide reduced T wave alternans (TWA) magnitude in patients with ventricular tachycardia. This antiarrhythmic drug effect lowered TWA
Area of Science:
- Cardiology
- Electrophysiology
- Pharmacology
Background:
- Microvolt T wave alternans (TWA) measures arrhythmia vulnerability.
- TWA magnitude is known to be heart rate-dependent.
- The impact of antiarrhythmic drugs on TWA remains largely uninvestigated.
Purpose of the Study:
- To investigate the effect of intravenous procainamide on TWA.
- To assess if procainamide alters TWA sensitivity for predicting ventricular tachycardia (VT).
Main Methods:
- Prospective evaluation in 24 subjects with inducible VT.
- TWA measurements were taken at baseline and after procainamide loading.
- Recordings were performed during normal sinus rhythm and atrial pacing at 100 and 120 bpm.
Main Results:
- Procainamide significantly decreased TWA magnitude across all heart rates (P<0.001).
- TWA sensitivity for VT induction decreased with procainamide administration.
- These TWA changes were independent of procainamide's direct antiarrhythmic effect on VT.
Conclusions:
- Acute procainamide loading reduces TWA magnitude.
- This reduction in TWA diminishes its predictive value for sustained VT induction.