[Significance of decreased washout rate in hypertrophic cardiomyopathy by exercise Tl-201 myocardial scintigraphy].

UNLABELLED

A clinical significance of decreased washout rate (WR) in hypertrophic cardiomyopathy by exercise thallium-201 myocardial scintigraphy was evaluated. Thirty-six patients with hypertrophic cardiomyopathy and normal coronary angiogram were categorized into 3 groups according to initial distribution (ID) and WR: decreased ID group (17 patients, ID group), normal ID but decreased WR group (9 patients, WR group) and normal ID and normal WR group (10 patients, N group).

RESULTS

(1) Cardio-thoracic-ratio and left ventricular end-diastolic pressure were higher in WR group than in other 2 groups. (2) Resting ejection fraction and left ventricular end-diastolic volume index did not differ in three groups. (3) Exercise ejection fraction was increased in N group, whereas it was not increased in ID or WR groups. It was increased in 47% of ID group, but were decreased or not changed in all patients of WR group. In conclusion, decreased WR in patients with hypertrophic cardiomyopathy may strongly suggest left ventricular myocardial damage.