PREVALENCE AND PROGNOSTIC-SIGNIFICANCE OF COMPLEX VENTRICULAR ARRHYTHMIAS AFTER CORONARY ARTERIAL BYPASS GRAFT-SURGERY

To assess the prevalence and long-term prognostic significance of complex ventricular arrhythmias after coronary arterial bypass graft surgery, 126 patients were studied by 24-hour ambulatory electrocardiographic recordings and cardiac catheterizations (including left ventricular, coronary arterial and bypass graft angiograms) before and 3 months after surgery, and then prospectively followed-up for a mean of 50 months. Complex ventricular arrhythmias (ventricular premature complexes > 30/hour, multiform and/or repetitive complexes) occurred more commonly after than before surgery (in 49 126 vs. 30 126 patients, P < 0.05). In 18 patients (14%) who had significant worsening of ventricular arrhythmias, the ejection fraction decreased significantly (from 56 ± 13% to 50 ± 15%, P < 0.05) after operation. During the period of follow-up, there were 4 witnessed sudden cardiac deaths. Complex ventricular arrhythmias tended to be more prevalent in patients who died suddenly (in 100%) compared to survivors (in 37%), but their presence did not predict the subsequent sudden death when ejection fraction was included in the stepwise regression model. None of the patients with an ejection fraction over 40% suffered sudden death despite the prevalence of complex arrhythmias in 32% of these patients. Thus, complex ventricular arrhythmias tend to occur more frequently after than before bypass surgery and their occurrence appears to be related to impairment of left ventricular function. Patients with well preserved ventricular function are at low risk of dying suddenly despite presence of complex ventricular arrhythmias after surgery. © 1990.