Prognostic significance of repetitive ventricular response in chronic coronary artery disease

A prospective study was conducted in 267 patients with angiographically defined coronary artery disease without documented ventricular tachycardia to determine the prognostic significance of repetitive ventricular response (RVR) after programmed electrical stimulation (PES). The patients were classified inducible if RVR with 3 or more echo beats (RVR greater than or equal to 3) could be induced. 89 patients without previous myocardial infarction (MI), 61 survivors of MI occurring between 6 weeks and 3 months before and 117 patients who had survived longer than 3 months after MI were studied. A standardized stimulation protocol with single (S1S2) and double (S1S2S3) extrastimuli during ventricular drive at a cycle length of 600, 500 and 430 ms with a current strength below 5 mA at the right ventricular apex was employed. Ventricular responses with 3 to 5 echo beats (RVR3-5) and with 6 and more echo beats (RVR greater than or equal to 6) were distinguished. In 68 (25%) patients RVR3-5 and in 38 (14%) patients RVR greater than or equal to 6 was observed; in 11 patients with RVR greater than or equal to 6 sustained VT was initiated which was monomorphic in 5 of them. The occurrence of RVR greater than or equal to 6 was related to the time interval to prior MI and most frequently found within 3 months of MI. A higher incidence of RVR greater than or equal to 6 was observed in more advanced CAD, although the angiographic findings were unable to predict the results of PES. During a mean follow up of 20 months 11 patients died, 8 suddenly, 3 in cardiac failure. Those who died had more extensive CAD, RVR greater than or equal to 3 was found in 4 of them and nonsustained VT in one. The sensitivity of RVR greater than or equal to 3 as a predictor of sudden death (SD) was 36% and the specifity 60%. The predictive value of inducibility of RVR greater than or equal to 3 as indicator of SD was 4% and the predictive value of noninducibility was 98%. It is concluded that in patients with chronic CAD without spontaneous VT, RVR with 3 more echo beats does not identify a predisposition to die suddenly.