Cardiac Hypertrophy in Idiopathic Dilated Congestive Cardiomyopathy

Although clinical studies indicate that patients with idiopathic dilated congestive cardiomyopathy who develop electrocardiographic or angiographic signs of left ventricular (LV) hypertrophy may survive longer, there is little morphologic evidence for such anatomic favorable or unfavorable prognostic groups. We studied 30 autopsied patients who died of dilated cardiomyopathy; of these, 15 died within 1 year of the first symptom of their disease (short-term survivors) and 15 patients died 1–14 years after initial symptoms (long-term survivors). There were no significant differences in sex, race, clinical presentation or cause of death between the groups, but there were significant morphologic differences. In the short-term survivors, average heart weight was S40 g and LV wall thickness was 1.0 cm, whereas in the long-term survivors, the average heart weight was 759 g and LV wall thickness was 1.3 cm (p < 0.001). LV cavity dilatation as measured by maximal transverse diameter from the postmortem angiograms did not differ between the two groups. These patients were compared with 10 autopsied patients with normal hearts and no clinical cardiac disease and 10 autopsied patients with volume overload secondary to valvular regurgitation. An LV hypertrophy/ dilatation index (thickness/diameter) was 0.17 ± 0.07 for the short-term survivors, 0.21 ± 0.07 for the long-term survivors, 0.38 ± 0.07 for volume overload patients, and 0.48:L 0.19 for normal subjects (F = 20.24, p < 0.001). Thus, in patients with hypertrophy due to volume overload, wall thickening increased with dilatation, returning the ratio of wall thickness to cavity size toward normal. In contrast, among the idiopathic congestive cardiomyopathies, dilatation was disproportionate to hypertrophy and the difference was most marked for short-term survivors.