Electrocardiographic, echocardiographic and ventriculographic characterization of hypertrophic non-obstructive cardiomyopathy.

HNCM tends to have more diffuse or generalized hypertrophy than HOCM, although these two types are not fundamentally different in aetiology (genetic). Extreme ASH is primarily related to a hereditary factor while HNCM, including apical hypertrophy, seems to be based on an abnormal disposition to produce myocardial hypertrophy in response to endogenous or exogenous stimulation such as catecholamines, chronic anoxia, hypertension or even aging. Hypertension by itself, however, can not be a cause of apical hypertrophy. The configuration of left ventricular hypertrophy in HCM can be divided roughly into several patterns: ASH, apical, postero-inferior, generalized or diffuse types, etc. ASH is not an essential morphology for HNCM. Apical hypertrophy is the only specific hypertrophic pattern which shows characteristic ECG abnormalities (giant negative T waves and high QRS voltage in left precordial leads). Inverted T waves combined with high QRS voltage tends to be a reflection of a localized hypertrophic portion in the left ventricular free wall. Abnormal Q waves associated with left axis deviation usually suggest marked septal hypertrophy. They seem to be related to conduction disturbances in myopathic septum.