Ventricular vulnerability assessed by programmed ventricular stimulation in patients with and without late potentials.

Abstract

Late potentials can be recorded noninvasively with the averaging technique in about one-third of patients with coronary heart disease in whom ventricular tachyarrhythmias have not been previously documented. The prognostic significance of these findings has not yet been established. Therefore, the presence or absence of late potentials was correlated to the results of programmed ventricular stimulation (single and double premature stimuli during sinus rhythm and a paced ventricular rhythm, cycle lengths 500, 430, 370, and 330 msec) in 110 male patients (age 52 + 5.9 years, mean SD). The end of the stimulation protocol was reached as soon as 4 or more ventricular echo beats (defined as an abnormal response) were induced. Late potentials were recorded in 40 patients (36.4%). The duration of late potentials was less than 20 msec in 12 patients, between 20 and 39 msec in 16 patients, and 40 msec or more in another 12 patients. In those patients with late potentials, four or more consecutive ventricular echo beats (repetitive ventricular response) were recorded more frequently (63%) than in those without (33%). The incidence of abnormal responses increased from 42% in those with late potentials of less than 20 msec to 56% in those with late potentials of between 20 to 39 msec and to 92% in those with late potentials of 40 msec or more. There was a significant correlation between left ventricular function and presence and duration of late potentials (X2 = 12.96; p < .0115) and between left ventricular function and the results of programmed ventricular stimulation (X2 = 16.24; p < .0003). In contrast, late potentials and the results of programmed ventricular stimulation were less closely associated (X2 = 5.49; p < .0643). In conclusion, late potentials proved to be a noninvasive indicator of abnormal left ventricular function, indicating an increase in ventricular vulnerability in patients that were free of symptomatic ventricular tachyarrhythmias. The predictive value of both late potentials and repetitive ventricular responses alone or in combination with regard to the occurrence of ventricular tachycardia or sudden death is still to be established. Circulation 68, No. 2, 275-281, 1983. IT HAS RECENTLY become possible to record electrical activity originating from abnormally conducting myocardium from the body surface with high-gain amplification and the averaging technique.1 16 These signals, which result from delayed ventricular activation (late potentials), have been recorded in patients with documented ventricular tachycardia. In a pilot study in postmyocardial infarction patients, we were able to show that the presence of late potentials predicted subsequent occurrence of ventricular tachycardia. 5 However, late potentials can also be recorded in about From the Medical Hospital B (Cardiology), University of Dusseldorf. Supported by the Johann A. Wiulfing Stiftung and the Sonderforschungsbereich 30 (Kardiologie) of the Deutsche Forschungsgemeinschaft. Address for correspondence: Prof. Dr. G. Breithardt, Medizinische Klinik B, Universitat Dusseldorf, Moorenstrasse 5, D-4000 Dusseldorf, Germany. Received July 23, 1982; revision accepted April 25, 1983. one-third of patients without previously documented ventricular tachycardia, especially those with left ventricular akinesia or dyskinesia.'3 The significance of these findings with respect to predicting the development of ventricular tachycardia has not yet been established. The purpose of this study was to correlate the presence of late potentials to the results of programmed ventricular stimulation in a group of patients in whom ventricular tachycardia has not been previously documented to get more insight into the mechanisms and potential prognostic value of late potentials in these patients. Patients and methods. One hundred ten male patients (mean age + SD 52 + 5.9 years) without previously documented tachycardia or fibrillation and without a history of resuscitation or syncope were studied. The findings in 27 patients concerning the noninvasive recording of late potentials have been included in a previous report.'3 All patients were informed about the Vol. 68, No. 2, August 1983 275 by guest on July 14, 2011 http://circ.ahajournals.org/ Downloaded from