Relationship Between Nonsustained Ventricular Tachycardia After Non–ST-Elevation Acute Coronary Syndrome and Sudden Cardiac Death

Abstract

Most studies examining the relationship between ventricular tachycardia (VT) after acute coronary syndrome and sudden cardiac death (SCD) were performed before widespread use of reperfusion, revascularization, or contemporary medical therapy and were limited to ST-elevation myocardial infarction. The incidence and prognostic implications of VT in patients with non-ST-elevation acute coronary syndrome receiving contemporary care have not been examined. The Metabolic Efficiency With Ranolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndrome-Thrombolysis in Myocardial Infarction 36 (MERLIN-TIMI 36) trial randomized 6560 patients hospitalized with a non-ST-elevation acute coronary syndrome to ranolazine or placebo in addition to standard therapy. Continuous ECG recording was performed for the first 7 days after randomization and evaluated in a blinded core laboratory. SCD (n=121) was assessed over a median follow-up of 1 year. A total of 6345 patients (97%) had continuous ECG recordings evaluable for analysis. Compared with patients with no VT (n=2764), there was no increased risk of SCD in patients with only ventricular triplets (n=1978, 31.2%) (1.4% versus 1.2%); however, the risk of SCD was significantly greater in patients with VT lasting 4 to 7 beats (n=1172, 18.5%) (SCD, 2.9%; adjusted hazard ratio, 2.3; P<0.001) and in patients with VT lasting at least 8 beats (n=431, 6.8%) (SCD, 4.3%; adjusted hazard ratio, 2.8; P=0.001). This effect was independent of baseline characteristics and ejection fraction. VT occurring within the first 48 hours after admission was not associated with SCD. Nonsustained VT is common after admission for non-ST-elevation acute coronary syndrome, and even short episodes of VT lasting 4 to 7 beats are independently associated with the risk of SCD over the subsequent year. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00099788.