The association of heart rate with adverse outcomes and recurrent heart failure hospitalization in peripartum cardiomyopathy.

Introduction: Understanding predictors of adverse outcomes in patients with peripartum cardiomyopathy (PPCM) is essential for risk stratification and prognosis. The aim of this study is to examine the relationship between heart rate (HR) at diagnosis and adverse outcomes in PPCM.

Methods: We conducted a multi-center cohort study to identify patients with PPCM (1993-2017) who met the inclusion criteria: left ventricular ejection fraction (LVEF) <40%, development of heart failure within the last month of pregnancy or within 5 months of delivery, and no other identifiable cause of heart failure with reduced ejection fraction. The primary composite outcome of major adverse events included recurrent heart failure hospitalization, need for extra-corporeal membrane oxygenation, left ventricular assist device, orthotopic heart transplant, or all-cause death. Using Cox proportional hazards models, we examined the relationship between categories of HR at diagnosis and adverse outcomes.

Results: A total of 177 women met criteria (81 with HR <100 bpm, 54 with HR 100-119 bpm, 42 with HR ≥120 bpm) with a mean age of 32 ± 7 years and median follow-up 3.6 years (IQR 1.1-8.2); 48 (27%) experienced the composite outcome. In a multivariable model adjusting for age, race, preeclampsia and hypertension, women with HR ≥ 120 bpm were four times more likely to experience major adverse events compared to women with HR < 100 bpm (HR 4.1, 95% CI 1.6-10.4) at the time of diagnosis. In a second multivariable model adjusting for the above covariates plus LVEF < 30%, QTc, and systolic blood pressure, those with HR ≥ 120 bpm were more likely to experience major adverse events compared to those with HR < 100 bpm (HR 3.31 (1.01-10.9), p = 0.049). Patients with HR <100 bpm were significantly more likely to have survival free from adverse events in survival analysis (p = 0.03).

Conclusion: Sinus tachycardia at diagnosis was associated with lower LVEF on presentation and higher rates of major adverse events in PPCM. Tachycardia may be an early prognostic indicator of outcomes in PPCM and could help identify high-risk patients for closer follow-up and earlier intervention.