Significant variability in the mode of ventricular tachycardia induction and its implications for interpretation of acute drug testing

Karen J. Beckman, Carlos E. Velasco, Jack Krafchek, Huang Ta Lin, Sharon A. Magro, Christopher R.C. Wyndham

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12 Scopus citations


Fifty-four patients with previous myocardial infarction and sustained ventricular tachycardia on fibrillation underwent two electrophysiologic studies in the drug-free state within 72 hours. Although the concordance of overall ventricular tachycardia induction over the 2 days was good (87% of patients), there was variability in the number of extrastimuii needed to induce sustained ventricular tachycardia on each day in 60% of patients. Of those in whom ventricular tachycardia was inducible on both days, 40% required additional extrastimuli and 20% required fewer extrastimuli. A change by two or more extrastimuli was found in 12% of patients. There was no correlation between the variability observed and multiple clinical and laboratory parameters (including the aggressiveness of the stimulation protocol); however, the direction of the variability (easier or harder to induce) correlated with changes in ventricular refractoriness. Inherent day-to-day variability may affect the reproducibility of electrophysiologic studies and influence the results of serial drug testing.

Original languageEnglish (US)
Pages (from-to)718-726
Number of pages9
JournalAmerican Heart Journal
Issue number3
StatePublished - Sep 1988


ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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