AN ECHOCARDIOGRAPHIC STUDY OF THE CLINICOPATHOLOGICAL POLYMORPHISM OF HYPERTROPHIC CARDIOMYOPATHY

An echocardiographic Study of 322 adults (age : 40 +/- 16 years), belonging to 20 families with hypertrophic cardiomyopathy (HCM), was undertaken. Affected subjects had a LV diastolic wall thickness > 13 mm. The patients were classified according to the distribution of left ventricular hypertrophy (LVH) and by Maron's classification : 189 subjects were normal, 127 were affected and 6 could not been classified. By Maron's classification : 3 % were type I, 33 % were type II, 58 % were type III and 6 % were type IV. LVH was asymmetrical in 95 % of cases (septum/posterior wall ratio > 1.3). The familial distribution of LVH of the 4 families in which HCM was genetically related to different loci (chromosome 11, 14 exon 13, 14 exon 8, fifth locus); the LVH was analysed from two short axis LV parasternal views and each plane was divided into 5 segments. The distribution of LVH was said to be identical between two first degree relations when all the same segments were affected, similar when they differed by only 1 or 2 segments and different when they differed by 3 or more segments. In the 26 pairs studied, LVH was identical in 2/26 (8 %), similar in 11/26 (42 %) and different in 13/26 (50 %). Familial HCM usually gives rise to asymetrical LVH affecting the septum and free wall. An identical distribution in 50 % of affected first degree relatives.