A medicament (A) for treating myocardial diseases associated with hypertrophy contains a bradycardic agent (I) and optionally another cardiac drug (II). ACTIVITY : Cardiant. In tests in a cat having severe hypertrophic cardiomyopathy, oral administration of cilobradine (Ia) twice daily at 0.3 mg/kg marked reduced the clinical symptoms (e.g. by reducing pain and normalizing the ECG) and also caused regression of the myocardial hypertrophy after 1 and 2 years. MECHANISM OF ACTION : Calcium ion channel blocker; beta -receptor blocker; i f channel blocker.