[Myocardial perfusion SPECT and isotopic ventriculography in obstructive and non-obstructive hypertrophic myocardiopathy].

Objective: To evaluate the role of myocardial perfusion SPET and radionuclide ventriculography in patients with hypertrophic cardiomyopathy (HC).

Methods: Exercise myocardial perfusion SPET with 99mTc-tetrofosmin and radionuclide ventriculography were performed in a consecutive series of 101 patients (54 15 years, 50 women, 55 with dynamic obstruction) diagnosed of HC by echo. Follow-up from the diagnosis was 9,9 6,7 years (1 to 28 years).

Results: Thirty six percent of patients had perfusion defects (non reversible in 15 and reversible in 21). In non obstructive HC higher number of patients with non reversible defects (p = 0.01 was obseved and in patients with no reversible defects higher incidence of pathologic Q waves in ECG (p = 0.01), Higher ventricular volumes (p < 0.05), lower ejection fraction (p = 0,0001) and longer time to peak emptying velocity (p < 0.05). There were 4 cardiac deaths, 15 syncopes, 18 pacemakers and 6 myectomy. Ejection fraction was higher in patients with syncope (p = 0,034) and there was no isotopic variable predictive of mortality, pacemaker or myectomy.

Conclusions: Neither SPET nor radionuclide ventriculography have a prognostic role in patients with HC, but patients with syncope have higher values of ejection fraction. Patients with non reversible defects have higher rate of pathologic Q waves in ECG, higher ventricular volumes and lower ejection fraction. This is indicative of evolution to dilated form of HC.