Inducibility of sustained monomorphic ventricular tachycardia as a prognostic indicator in survivors of recent myocardial infarction: a prospective evaluation in relation to other prognostic variables
T Cripps,
ED Bennett,
AJ Camm,
and
DE Ward
Department of Cardiological Sciences, St. George's Hospital Medical School, London, England.
The prognostic significance of sustained monomorphic ventricular tachycardia inducible with up to three extrastimuli was assessed in relation to other prognostic markers, including clinical assessment, signal-average electrocardiogram (ECG), Holter monitoring, ejection fraction measurement and exercise testing, in 75 patients after recent myocardial infarction. Among eight patients with inducible sustained monomorphic ventricular tachycardia, six suffered arrhythmic events during a median follow-up period of 16 months. No patient without inducible sustained monomorphic ventricular tachycardia suffered an arrhythmic event. Multivariate analysis showed that of all the variables examined, inducible sustained monomorphic ventricular tachycardia was the only independent predictor of arrhythmic events during the follow-up period. The sensitivity for predicting arrhythmic events by this response was 100%, the specificity 97% and the positive predictive accuracy 75%. Individually, the other prognostic variables were less sensitive and much less accurate predictors of arrhythmic events, but the combination of the occurrence of acute phase complications or frequent ectopic activity with an abnormal signal-averaged ECG approached the sensitivity and accuracy of inducible sustained monomorphic ventricular tachycardia. The prognostic utility of programmed ventricular stimulation in patients with recent myocardial infarction is limited because comparable information can be obtained less invasively. However, the test may have a role in selecting therapy in patients judged to be at risk from arrhythmias on the basis of noninvasive assessment.
