[Hypertrophic cardiomyopathy. Data from Doppler echocardiography].

Hypertrophic cardiomyopathy (HCM) often involves the interventricular septum in the absence of any other cardiac or systemic abnormality capable of explaining this hypertrophy. M mode echocardiography shows septal hypertrophy and a posterior left ventricular wall of normal thickness. Two-dimensional echocardiography gives a better idea of the spatial distribution of the hypertrophy, especially in the short axis parasternal views. Obstruction to left ventricular ejection is another feature of this condition but presence of the obstruction remains a subject of controversy. Doppler studies give easy access to the changes in intraventricular hemodynamics and thereby contribute to fueling the controversy between supporters of intraventricular obstruction and those who prone the theory of hypercontractility. Color coded Doppler enables visualisation of the acceleration of blood flow in the left ventricular outflow tract and the demonstration of mitral regurgitation, which is always present in HCM with obstruction. The echocardiographic evaluation has been facilitated by the recent introduction of transesophageal probes. Doppler studies of mitral blood flow also enable evaluation of left ventricular diastolic function. The evaluation of left ventricular relaxation is often difficult and inaccurate in patients with supraventricular arrhythmias, intraventricular conduction defects or mitral regurgitation. Nevertheless, Doppler echocardiography remains the most reliable and useful method of evaluating HCM.