Letter by Andreoletti et al regarding article, "contribution and risks of left ventricular endomyocardial biopsy in patients with cardiomyopathies: a retrospective study over a 28-year period".

BACKGROUND Use of left ventricular (LV) endomyocardial biopsy (EMB) to investigate cardiomyopathies is currently discouraged because it is considered riskier than and as contributive as right ventricular (RV) biopsy. The aim of our study is to report our experience with this option and to discuss its advantages and disadvantages. METHODS AND RESULTS In our center from 1983 to 2010, 4221 patients underwent diagnostic EMB. In particular, 2396 (56.8%) underwent biventricular EMB, 1153 (27.3%) underwent selective LVEMB, and 672 (15.9%) underwent selective RVEMB. The rate of complications and histological findings were retrospectively analyzed. The periprocedural major complication rate (perforation with or without cardiac tamponade, embolization) was 0.33% for LVEMB and 0.45% for RVEMB, with a significant decrease in the rate of major complications with time (from 1.6% and 1.9% in 1983-1988 to 0% and 0.3% in 2007-2013, respectively; P<0.001 for both), denoting a steep learning curve. No patients died. When the structural and functional abnormalities affected exclusively the LV, the diagnostic yield of LVEMB was 97.8% compared with 53% for RVEMB. Conversely, when the echocardiographic presence of increased wall thickness, local or global ventricular dilation, or dysfunction also involved the RV, the diagnosis was reached in 98.1% of LVEMBs and 96.5% of RVEMBs. This discrepancy was particularly evident for myocarditis, whereas in infiltrative and storage diseases, the histological abnormalities were always detectable in both ventricles. CONCLUSIONS LVEMB is a safe procedure with very low transient complications, comparable to RVEMB. It appears diagnostically more contributive than RVEMB in patients with cardiomyopathies and clinically preserved RV.