[Distribution of myocardial damage in patients with hypertrophic cardiomyopathy: evaluation by exercise thallium-201 scintigraphy].

The characteristic of myocardial damage in hypertrophic cardiomyopathy (HCM) was evaluated as to whether the damage is limited to the hypertrophied wall or extends throughout the entire wall. The myocardial damage was detected by exercise thallium-201 (Tl-201) scintigraphy and was evaluated using circumferential profile analysis, calculation of initial uptake and washout rate. Eleven patients with asymmetrical hypertrophy (ASH), whose septal and posterior wall thickness ratio exceeded 1.3 on left ventriculography and biventriculography, and 13 age-matched control subjects without heart disease were studied. The mean values of initial uptake in both groups did not differ significantly, but the washout rate for the entire heart was significantly decreased only in the HCM group (p < 0.05). All of the regional washout rates (antero-septal, apical and postero-lateral) were significantly decreased in the HCM group (p < 0.05), without any difference between the hypertrophied wall and the non-thickened free wall being noted. These results demonstrated that the analysis of myocardial damage by exercise Tl-201 scintigraphy using calculation of the washout rate is a very sensitive means of detecting myocardial damage in HCM, and that such myocardial damage is not restricted to the hypertrophied wall, but rather extends to the entire wall, including the free wall which is not thickened.