Estimating myocardial damage and the need for surgery in patients with valvular heart disease by Tl-201 SPECT.

Left ventricular myocardial disorders due to volume overload were investigated by Tl-201 myocardial SPECT (Tl-201 SPECT) in patients with aortic or mitral regurgitation, and its utility for timing cardiac valve replacement was studied. There were significant correlations between Tl-201 scores and electrocardiographic changes and the New York Heart Association classification. There also were favorable correlations between Tl-201 scores and the left ventricular end-diastolic dimension and between Tl-201 scores and left ventricular ejection fraction, and a close relationship between the presence of a left ventricular myocardial disorder and left ventricular diameter. These results suggest that myocardial perfusion abnormalities and left ventricular myocardial disorders may accompany left ventricular dilatation owing to volume overload. After valve replacement, left ventricular end-diastolic dimension normalized, and Tl-201 scores improved slightly, suggesting normalization of myocardial perfusion. When moderate or more severe Tl-201 defects are present on Tl-201 SPECT images, in addition to inverted Tl-201 waves on the electrocardiogram or a left ventricular end-diastolic dimension of 65 mm or more, cardiac valve replacement should be considered.