[Ischemic clinical forms of hypertrophic cardiomyopathies: differential diagnosis with myocardial infarction. Apropos of 15 cases].

This study reports 15 cases of ischaemic clinical forms of hypertrophic cardiomyopathy (HCM). In this retrospective study over a 3 year period, 15 patients with HCM presented with clinical and electrocardiographic signs simulating unstable angina (N = 5) or myocardial infarction (N = 10). All patients had chest pain lasting at least 20 minutes with pseudo-ischaemic ECG changes. Two patients were given thrombolytic therapy. The clinical and enzymatic outcome and results of complementary investigations (including coronary angiography) confirmed the absence of coronary artery disease. The diagnostic of HCM was made by echocardiography. These cases were all apparently primary forms of HCM without intraventricular pressure gradient under basal conditions. Three of the patients were known cases of HCM but the condition was diagnosed after the ischaemic presentation in the other cases. Eight of them had however been considered to have had coronary insufficiency for an average of 5 years. The clinical presentation of HCM represents a difficult differential diagnostic problem with myocardial infarction. Echocardiography is of little help in distinguishing the 2 diseases as septal hypokinesis is often observed in HCM. The clinical course usually reestablishes the diagnosis within a few hours but the delay is often too long in this situation of therapeutic emergency and the indications of thrombolysis may be wrongly posed. Although there is no available formal means of distinguishing the two conditions, this study underlines that this clinical form of HCM is not rare and that the diagnosis should be keep in mind with the other differential diagnoses of myocardial infarction.