Significance of timing programmed electrical stimulation after acute myocardial infarction

• Published in: Journal of the American College of Cardiology 1986-12, Vol.8 (6), p.1279-1288
• Main Authors: Kuck, Karl-Heinz, Costard, Angelika, Schlüter, Michael, Kunze, Klaus-Peter
• Format: Article
• Language: English
• Subjects: Arrhythmias, Cardiac - etiology; Biological and medical sciences; Cardiac Pacing, Artificial; Cardiology. Vascular system; Coronary heart disease; Electrocardiography; Exercise Test; Heart; Humans; Medical sciences; Myocardial Infarction - complications; Myocardial Infarction - physiopathology; Refractory Period, Electrophysiological; Risk
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/S0735-1097(86)80298-4

To assess the influence of time on the inducibility by programmed electrical stimulation of ventricular arrhythmias after acute myocardial infarction, 18 patients were studied on day 5 and day 24 after infarction with a stimulation protocol employing a maximum of three right ventricular extrastimuli during sinus rhythm and at three paced cycle lengths. All patients were without documented sustained ventricular arrhythmia (sustained ventricular tachycardia or ventricular fibrillation) before the investigation. Sustained ventricular arrhythmia was induced in two patients on day 5, but in nine on day 24 after infarction. This difference in incidence was statistically significant (p < 0.05), as was the change in the distribution ratio of induced sustained ventricular arrhythmia from day 5 to day 24 (p < 0.05). The types of arrhythmia induced on day 24 were sustained ventricular tachycardia with a mean cycle length of 207 ms in six cases (five mono-morphic, one polymorphic), and ventricular fibrillation in three cases. These nine patients did not differ from the remaining nine patients in maximal serum creatine kinase, infarct site, number of stenosed coronary arteries, global left ventricular ejection fraction (47 ±7% versus 46 ± 10%) and results of 24 hour ambulatory electrocardiographic (Holter) monitoring, but they had a significantly shorter right ventricular effective refractory period (223 ± 10 ms versus 259 ± 28 ms; p < 0.05). During the follow-up period of 24 ± 5 months no patient died, had syncopal attacks or developed spontaneous episodes of sustained ventricular arrhythmia. The timing of programmed electrical stimulation with a maximum of three right ventricular extrastimuli strongly influences the inducibility of sustained ventricular arrhythmias after acute myocardial infarction. The high inducibility on day 24 after infarction of sustained polymorphic ventricular arrhythmias or of monomorphic ventricular tachycardias with a short cycle length did not correlate with the good clinical course of this group of patients.