Sex differences in patients with acute myocarditis: a cohort study

Abstract Background Sex differences in patients with acute myocarditis (AM) are poorly understood. Purpose We aimed to study sex differences in AM patients including medical history, clinical presentations, diagnostics, and in-hospital outcomes. Methods We enrolled 215 patients with a diagnosis of AM at a tertiary hospital between January 2000 and December 2018 into a retrospective cohort study. All patients were hospitalized on an intensive care unit (ICU) with continuous monitoring. We compared sex differences in clinical presentation including ECG, prior medical history, cardiac biomarkers, cardiac imaging (echocardiography and cardiac MRI) and in-hospital outcomes including incident arrhythmia. Results Median age was 38 years and 27% were female. Overall, the most common presenting symptoms were chest pain (84%), dyspnea (34%) and fever (29%). Compared to men, women presented more often with dyspnea (47% vs 29%, p=0.015), were older (49 vs 36 years, p<0.001) and had more comorbidities including hypertension (33% vs 18%, p=0.032) and diabetes (14% vs 4%, p= 0.033). In the presenting ECG, female patients were more likely to present with T-wave inversion (46% vs 27%, p=0.017) and less likely with ST elevation (9% vs 39%, p<0.001) compared to male patients. The overall hospital stay was longer in women compared to men (7 vs 5 days, p=0.021) with no difference in the length of ICU stay (2.8 vs 3.0 days, p=0.782). Cardiac biomarkers including high-sensitivity troponin T (median 426 vs 665 ng/l, p=0.415) and CK-MB (median 23 vs 24 U/l, p=0.888) were not different, but women had higher NT-proBNP levels (median 2380 vs 353 ng/l, p=0.032). Left ventricular ejection fraction (LVEF) was similar between sexes, both by transthoracic echocardiography (55% vs 55%, p=0.864) and cardiac MRI (58% vs 56%, p=0.919). During monitoring, atrial fibrillation/atrial flutter occurred in 4% of patients, non-sustained ventricular tachycardia in 15%, sustained ventricular tachycardia in 4% and ventricular fibrillation/cardiac arrest in 2%. While we did not find a sex difference in atrial fibrillation/atrial flutter, women tended to have more severe ventricular arrhythmia (Figure). Conclusion Women constituted a quarter of our AM cohort. Compared to men, women were older at the time of AM diagnosis, had more comorbidities, showed different clinical and ECG findings, and were hospitalized longer. While LVEF was similar, women had higher levels of NT-proBNP.Central Illustration