Ultrasound characteristics of myocardial hypertrophy in patients affected by hypertrophic cardiomyopathy.

A study of the extent and local distribution of the heart muscle hypertrophy affecting the left ventricle and the septum has been performed in 70 hypertrophic cardiomyopathy patients. According to these signs the patients have been distributed into 5 types. Type I, where the hypertrophy affected only the interventricular septum, appeared in 14.2% of the cases. In type IIa the anterior wall of the ventricle was simultaneously affected (37.1%), in type IIb it was also the lateral wall of the ventricle (30.0%). Type III manifested hypertrophy of the posterior wall (4.3%), type IV affected the apical portion of the left ventricle (8.5% of the patients). Under the heading of type V there figured patients who had a concentric hypertrophy of the whole left ventricle including the septum (5.7%). Among the obstructive forms we revealed especially the types Ia, IIa, IIb. Using the M-mode alone, detection of the hypertrophy was impossible in such patients who had isolated affection of the dorsal part of the septum, the anterolateral or the apical portion of the left ventricle (type Ib, IV and some of the type IIa and IIb patients--a total of 13%). Signs of asymmetrical septal hypertrophy were lacking in 23% of the patients.