A rare familial cardiomyopathy characterized by the dilation of left ventricle and progressively impairing of systolic ventricular function, in the absence of abnormal loading conditions or coronary artery disease sufficient to cause global systolic impairment. The disease may cause heart failure or arrhythmia. The disease is isolated when no additional atypical cardiac or extracardiac manifestations are present. [From Orphanet]