Ischemia detected on continuous electrocardiography after acute coronary syndrome: observations from the MERLIN-TIMI 36 (Metabolic Efficiency With Ranolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndrome-Thrombolysis In Myocardial Infarction 36) trial.

Abstract

The purpose of this study was to assess the relationship between ischemia detected on continuous electrocardiographic (cECG) recording and cardiovascular outcomes after acute coronary syndrome (ACS). The small size of prior studies evaluating cECG prevented full evaluation of the risk associated with ischemia across subpopulations and compared with other methods of risk stratification. Ranolazine, a new antianginal agent, reduces ischemic symptoms in patients with chronic angina and after ACS but the anti-ischemic effect, as detected by cECG, is not known. In all, 6,560 patients hospitalized with non-ST-segment elevation ACS were randomly assigned to ranolazine or placebo in the MERLIN-TIMI 36 (Metabolic Efficiency With Ranolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndrome-Thrombolysis In Myocardial Infarction 36) trial. The cECG was performed for 7 days after randomization. Outcomes were followed for a median of 348 days. Clinical events that occurred during cECG recording were excluded from analysis. A total of 6,355 (97%) patients had cECG recordings evaluable for ischemia analysis. Patients with >or=1 episode of ischemia on cECG (n = 1,271, 20%) were at increased risk of cardiovascular death (7.7% vs. 2.7%, p < 0.001), MI (9.4% vs. 5.0%, p < 0.001), and recurrent ischemia (17.5% vs. 12.3%, p < 0.001). The relationship with cardiovascular death was independent of baseline characteristics or elevated biomarkers (adjusted hazard ratio: 2.46, p < 0.001). Ischemia on cECG was associated with significantly worse outcomes in several subgroups. Ranolazine did not reduce the rate of ischemia detected on cECG (19.9% vs. 21.0%, hazard ratio: 0.93, p = 0.21). In more than 6,300 patients with ACS, ischemia detected on cECG occurred frequently and was strongly and independently associated with poor cardiovascular outcomes, including cardiovascular death. Continuous ECG monitoring to detect ischemia after ACS may help to identify patients at increased risk. (Metabolic Efficiency With Ranolazine for Less Ischemia in Non-ST Elevation Acute Coronary Syndromes [MERLIN]; NCT00099788).