THE PREDICTIVE VALUE OF ADMISSION HEART-RATE ON MORTALITY IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

The purpose of this study was to assess the predictive value of admission heart rate (HR) for in-hospital and 1 year post-discharge mortality in a large cohort of patients hospitalized for acute myocardial infarction (MI). Data were derived from the SPRINT-2 secondary prevention study population, and included 1044 patients (aged 50-79), hospitalized in 14 coronary care units in Israel with acute MI in the years 1985-1986, before the beginning of thrombolytic therapy in acute MI. Demographic, historical and medical data were collected for each patient. All deaths during initial hospitalization and 1 year post-discharge were recorded. In-hospital mortality was 5.2% for 294 patients with HR <70 beats/min, 9.5% for 532 patients with HR 70-89 beats/min, and 15.1% for 323 patients with HR greater than or equal to 90 beats/min (p < 0.01). One year post-discharge mortality was 4.3% for patients with HR <70 beats/min, 8.7% for patients with HR 70-80 beats/min and 11.8% for patients with HR greater than or equal to 90 beats/min (p < 0.01). An increasing trend of mortality with higher HR was confined to patients with mild CHF (p = 0.02) and likely to patients with absent CHF (p = 0.06), but this post hoc observation requires confirmation in larger groups. The combination of high admission HR (greater than or equal to 90 beats/min) and a systolic blood pressure <120 mmHg was a powerful predictor of in-hospital mortality. Multivariate analysis showed that admission HR was an independent risk factor for in-hospital and 1 year post-discharge mortality. An increase in HR of 15 beats/min was associated with average estimated increases of in-hospital and 1 year post-discharge mortality of 36 and 45%, respectively. This study demonstrates that elevated admission HR is an independent predictor of in-hospital and subsequent mortality in patients with acute MI. Admission HR is associated with mortality in patients with mild CHF and likely also in counterparts without CHF. The association is clearly seen in men and is of similar magnitude, although not statistically significant for 1-year mortality, in women.