HAND1 loss-of-function within the embryonic myocardium reveals survivable congenital cardiac defects and adult heart failure.

Aims: To examine the role of the basic Helix-loop-Helix (bHLH) transcription factor HAND1 in embryonic and adult myocardium.

Methods And Results: Hand1 is expressed within the cardiomyocytes of the left ventricle (LV) and myocardial cuff between embryonic days (E) 9.5-13.