Atypical left bundle branch block in dilative "burned-out" phase of hypertrophic cardiomyopathy.

We present the case of a 70-year-old man admitted in congestive heart failure. The patient was diagnosed 22 years ago of hypertrophic cardiomyopathy (HC). ECG showed a very peculiar and pathological form of left bundle branch block (LBBB). 2D-echocardiogram revealed a dilated left ventricle (LV) and ejection fraction of 25%. LV remodeling represents an important component of the pathophysiology of HC and, paradoxically, some patients develop LV wall thinning, systolic dysfunction, and congestive heart failure (in the absence of coronary artery disease). This evolution is designated as "end-stage" or "burned-out"phase. We present this rare LBBB and his pathological evolution along the time as unique manifestation of this "burned-out" phase. The mechanism of this wall thinning remains unclear but changes in ECG may alert us about it.