Use of programmed electrical stimulation to predict sudden death after myocardial infarction.

The use of programmed ventricular stimulation to identify patients at risk for sudden cardiac death following myocardial infarction has not yet been firmly established. The repetitive ventricular response following extrastimuli does not appear to be useful in identifying patients at risk and should not be used to guide antiarrhythmic therapy. Similarly, the response to single and/or double ventricular extrastimuli delivered at twice diastolic threshold from a single right ventricular site during normal sinus rhythm and ventricular pacing also does not appear to be helpful in identifying patients at risk for life-threatening ventricular arrhythmias. A more vigorous stimulation protocol that involves more than one right ventricular site and increased current strength may be necessary to elicit a predictive electrophysiologic response. The need for a more vigorous stimulation is suggested by two preliminary studies. Confirmation of initial reports is necessary. The predictive value of the response to programmed ventricular stimulation must be compared with other noninvasive and invasive measurements of left ventricular dysfunction and the degree of spontaneous ventricular ectopy to determine its superiority or to ascertain multiple variables that can be used together to identify those patients most likely to die suddenly after myocardial infarction. Stimulation protocols used during programmed stimulation must have sufficient sensitivity without sacrificing specificity. A concerted effort using uniform stimulation protocols in large numbers of patients is essential to resolve this important clinical problem.