Demographic features and prevalence of myocarditis in patients undergoing transarterial endomyocardial biopsy for unexplained cardiomyopathy

BACKGROUND: The diagnosis of myocarditis is still a challenge. The true incidence of the disease is unknown due to great variation in clinical manifestations. OBJECTIVE: The aim of this study was to identify the demographic features and in-hospital prevalence of myocarditis in patients undergoing transarterial endomyocardial biopsy (EMB) for unexplained cardiomyopathy. PATIENTS AND METHODS: This was a prospective observational study. We recruited all patients with unexplained cardiomyopathy presented at Assiut University Hospital from January 2014 till December 2014. The inclusion criteria were namely acute symptoms of heart failure, worsening of ejection fraction (EF) despite optimized therapy, hemodynamically significant arrhythmias, heart failure with concurrent rash, fever, or peripheral eosinophilia and new-onset cardiomyopathy in the presence of known amyloidosis. We excluded patients with uncontrolled hypertension, diabetes mellitus, ischemic, congenital, rheumatic heart disease, peripartum cardiomyopathy, cardiotoxic exposure, alcoholic and familial cardiomyopathies. All patients were subjected to full examination with ECG, echocardiography and coronary angiography, and then 3 EMB samples via femoral artery were taken from the LV. The histopathological examination of all biopsies was done. RESULTS: Out of the 1100 patients admitted to our department, 15 patients (1.4%), who had unexplained cardiomyopathy were included in our study. Seventy-three percent were males with mean age 37.8 ± 17 y. 87% were from rural areas, and 73.3% presented with dyspnea grade III to IV for a duration period that varied from 2 to 8 weeks. 33% had an EF > 40%. 33 EMB samples from 11 patients were examined. 7 out of 11 patients (63.6%) proved to have myocarditis on pathological examination, 5 of them had active myocarditis, 1 had chronic myocarditis and 1 had borderline myocarditis. Three patients (27.3%) had no pathological evidence of inflammation and one patient (9.1%) had cardiac amyloidosis. Four out of 15 patients (26.7%) did not undergo EMB because of LV thrombus or bleeding tendency. None of our patients had any complication from EMB. CONCLUSION: The in-hospital prevalence of myocarditis is high among patients with unexplained cardiomyopathy. EMB via femoral artery is safe and essential in confirming the diagnosis.