Ventricular tachyarrhythmia after coronary bypass surgery: incidence and outcome.

Background: Ventricular tachyarrhythmia after coronary artery bypass graft is common and the occurrence has been described, but the incidence and risk factors are not well defined.

Aim: To evaluate the incidence of arrhythmias and to detect high-risk populations.

Methods: In this prospective study, 856 consecutive patients undergoing coronary artery bypass graft were monitored for new-onset ventricular tachyarrhythmias: non-sustained monomorphic ventricular tachyarrhythmia, sustained monomorphic ventricular tachyarrhythmia, sustained polymorphic ventricular tachyarrhythmia, and ventricular fibrillation. Detailed analyses of the clinical, demographic, echocardiographic, and surgical findings and arrhythmias occurrence was carried out during 6 months of follow-up.

Results: The incidence of ventricular tachyarrhythmia was 26.6% (17.6% non-sustained monomorphic ventricular tachycardia, 5.5% sustained monomorphic ventricular tachycardia, 0.8% sustained polymorphic ventricular tachycardia, and 2.7% ventricular fibrillation). The strongest degrees of statistical significance were for low ejection fraction (p = 0.01) and ischemic heart disease (p = 0.02). The incidence of ventricular fibrillation (61%) was greatest in the first 48 h after surgery. Postoperative myocardial infarction (p = 0.03) and hemodynamic instability (p = 0.05) were also predictors of arrhythmia occurrence. Recurrence of arrhythmia was highest in the ventricular fibrillation group (52%). The correlations between tachyarrhythmia, age, sex, electrolyte disorders, body mass index, and systemic or pulmonary hypertension were not significant.

Conclusion: In view of the strong relationship between ventricular arrhythmias and low ejection fraction, ischemic heart disease, coronary artery disease severity, postoperative myocardial infection, and hemodynamic impairment, continuous monitoring is necessary, especially in the first 48 h after coronary artery bypass surgery.