Blood pressure and heart rate predict outcome in patients acutely admitted with suspected myocarditis without previous heart failure

OBJECTIVE: The study investigated the prognostic impact of blood pressure and heart rate in patients acutely admitted with suspected myocarditis without previous heart failure who underwent endomyocardial biopsy. METHODS AND RESULTS: In our prospectively planned study SBP, DBP, mean arterial blood pressure (MAP) and ECGs on admission were analyzed retrospectively in 175 patients with suspected myocarditis, who underwent endomyocardial biopsy between 1994 and 2007. Patients were followed up for a median of 53 ± 41 months, corresponding to a total follow-up of 9337 patient months. The primary endpoint was the time to cardiac death or heart transplantation, which occurred in 39 patients (22%). Baseline SBP was inversely associated with primary endpoint occurrence. Per 1 mmHg increase in SBP, the hazard ratio for the primary endpoint decreased by 4.3% hazard ratio = 0.96, confidence interval (CI) = 0.94-0.98, P < 0.001. The increased risk at a SBP below the mean value was confirmed after adjusting for the known independent predictors immunohistological signs of inflammation in biopsy samples, New York Heart Association functional class, and lack of β-blocker treatment (hazard ratio = 2.78, CI = 1.25-6.18, P = 0.012). In the presence of all risk predictors, hazard ratio for primary endpoint was 4.97 (CI = 2.28-10.83, P < 0.001). In a subgroup analysis of patients without β-blocker treatment, atrial fibrillation or pacemaker, a high heart rate was also associated with poor outcome (hazard ratio = 2.92, CI = 1.02-8.29, P = 0.045). CONCLUSION: In patients with suspected myocarditis without previous chronic heart failure low SBP, DBP and MAP were predictors of poor outcome. However, in patients not treated with β-blockers, a high heart rate was a predictor for cardiac death or heart transplantation.