The usefulness of left ventricular endomyocardial biopsy in clinical decision making in patients with unexplained heart failure

Introduction
In recent years, the recommendations for an endomyocardial biopsy (EMB) were significantly extended. However, the proposed criteria are based on the consensus of experts and require further clinical trials.

Aim
To present the results of our diagnostic and therapeutic management based on left ventricular EMB (LV-EMB) in patients with unexplained heart failure (HF).

Material and methods
LV-EMBs were performed between August 2016 and March 2019. Bioptates analysis included histological, immunohistochemical and viral genome examinations. Patients meeting the inclusion criteria had additional immunosuppressive treatment.

Results
LV-EMBs were performed in 30 patients. The mean ± SD age was 38.9 ±7.6 years. About 75% of patients were in NYHA class III or IV, eight were in cardiogenic shock, and four required intra-aortic balloon pump support. Fourteen patients had myocarditis and four had a viral infection. In 9 patients, steroid therapy was implemented. During the mean ± SD observational period of 10.5 ±8.1 months, all patients survived, and 11 had an ejection fraction (EF) of over 35%, of whom 6 (66%) were on additional immunosuppressive therapy and 5 (24%) on standard HF therapy (HR = 2.85; 95% CI: 0.86–9.36; p = 0.08). An increase of > 20 percentage points in the absolute EF was observed in 4 (44%) patients on steroid therapy and 3 (14%) on standard HF therapy (HR = 2.32; 95% CI: 0.51–10.39; p = 0.27).

Conclusions
An LV-EMB performed by skilled physicians is a safe procedure, verifies the cardiac magnetic resonance results, and allows the use of additional therapeutic options in patients with unexplained HF.