Prognostic significance of nonsustained ventricular tachycardia identified postoperatively after coronary artery bypass surgery in patients with left ventricular dysfunction.

INTRODUCTION: Nonsustained ventricular tachycardia (NSVT) occurs frequently in the postoperative period (< or = 30 days) after coronary artery bypass graft (CABG) surgery, a setting where many factors may play a role in its genesis. The prognosis of NSVT in this setting in patients with left ventricular (LV) dysfunction is unknown. This study was designed to assess its significance. METHODS AND RESULTS: We compared the outcome of untreated patients enrolled in the Multicenter Unsustained Tachycardia Trial with coronary artery disease (CAD), LV dysfunction, and NSVT identified postoperatively after CABG (n = 228; mean age 67 years, 84% males) versus nonpostoperative settings (n = 1,302; mean age 66 years, 85% males). Sustained monomorphic ventricular tachycardia was induced in 27% and 33% (P = 0.046) of patients with postoperative and nonpostoperative NSVT, respectively. The 2- and 5-year rates of arrhythmic events were 6% and 16%, respectively, in postoperative patients versus 15% and 29% in nonpostoperative patients (unadjusted P = 0.0020, adjusted P = 0.0082). The 2- and 5-year overall mortality rates were 15% and 36%, respectively, for postoperative patients versus 24% and 47% for nonpostoperative patients (unadjusted P = 0.0005, adjusted P = 0.027). Patients whose NSVT was identified early (<10 days) versus late (10-30 days) after CABG had significantly lower 2- (13% vs 23%) and 5-year (30% vs 52%) mortality rates (unadjusted P = 0.024, adjusted P = 0.018). CONCLUSION: In this population of patients with CAD and LV dysfunction, the occurrence of postoperative NSVT, especially within 10 days after CABG, portends a far better outcome than when it occurs in nonpostoperative settings. This suggests that in a such setting, NSVT represents a less specific risk factor for future events and should be considered when assigning risk and treatment of similar patients.

Duke Scholars

Author Kerry L. Lee Biostatistics & Bioinformatics, Division of Biostatistics