Prospective Evaluation of Diagnostic Performance and Safety of Implementing a Biventricular Approach for Endomyocardial Biopsy in Patients With Suspected Myocarditis

Background: Previous retrospective analyses have suggested that biventricular (BV) endomyocardial biopsy (EMB) is superior to right (RV) or left ventricular (LV) EMB only in diagnosing patients with suspected myocarditis. Aim: To prospectively assess the feasibility, safety and diagnostic yield of BV EMB in consecutive patients with suspected myocarditis. Methods: Five to six EMBs were taken from the RV and LV under fluoroscopic guidance. Biopsies were analyzed in a core lab by highly experienced investigators (KK, RK) Myocarditis/myocardial in[[Unable to Display Character: fl]]ammation was de[[Unable to Display Character: fi]]ned as the detection of ≥14 infiltrating leukocytes/mm2 (CD3 T-lymphocytes and/or CD68 macrophages) in addition to enhanced HLA class II expression in professional antigen-presenting immune cells. Results: 100 consecutive patients (mean age 44 ± 15 years) with clinically suspected myocarditis were included. RV EMB was attempted in 100 patients, in 3 the procedure was abandoned due to unsatisfying positioning on the guiding catheter, in 1/97 RV EMBs were inadequate with no myocardial tissue obtained. LV EMB was attempted in 97 patients, in 3, LV EMB was not performed due to presence of LV thrombi, in 1/97 patient LV EMBs were inadequate with no myocardial tissue obtained. Major complication rate for LV EMB was 0% and for RV EMB, 1% (pericardial tamponade requiring surgical revision). Results of adequate BV EMBs were analyzed in 92 patients. On BV EMB, myocarditis was diagnosed in 61/92 patients. When considering LV EMB only, the diagnosis would have been missed in 3/61, when considering RV EMB only in 7/61 patients. Conclusion: BV EMB is feasible and safe in the majority of patients with suspected myocarditis and yields in a superior diagnostic performance as compared to a single ventricle EMBs.