Myocarditis and long-term survival in peripartum cardiomyopathy

Background: The reported mortality rate of peripartum cardiomyopathy (PPCM) is high, although the potential for spontaneous recovery of ventricular function is well established. The prevalence of myocarditis in PPCM has varied widely between studies. The purposes of this study were to define the long-term prognosis in a referral population of patients with PPCM, to determine the prevalence of myocarditis on endomyocardial biopsy in this population, and to identify clinical variables associated with poor outcome. Methods: We analyzed clinical, echocardiographic, hemodynamic, and histologic features of 42 women with PPCM evaluated at our institution over a 15-year period. Each patient underwent an extensive evaluation, including echocardiography, endomyocardial biopsy, and right heart catheterization. Data were analyzed to identify features at initial examination associated with the combined end point of death or cardiac transplantation by the use of Kaplan-Meier survival curves and a Cox proportional hazards model. Results: Three (7%) patients died and 3 (7%) patients underwent heart transplantation during a median follow-up of 8.6 years. Endomyocardial biopsy demonstrated a high prevalence of myocarditis (62%), but the presence or absence of myocarditis was not associated with survival. Of the prespecified variables assessed, only decreased left ventricular stroke work index was associated with worsened outcome. Conclusions: In patients with PPCM, (1) long-term survival is better than has been historically reported, (2) the prevalence of myocarditis is high, and (3) decreased left ventricular stroke work index is associated with worse clinical outcomes.