Background. We sought to determine the relationship between 99mTc-sestamibi washout and myocardial properties in hypertrophic cardiomyopathy (HCM) patients. Methods and Results. Twenty-four HCM patients underwent biventricular cardiac cathe- terization, with a micromanometer-tipped catheter, both at rest and during atrial pacing, echocardiography and myocardial 99mTc-sestamibi scintigraphy at rest. The 99mTc-sestamibi washout rate (WR) was calculated using initial and delayed planar images. The HCM patients were divided into two groups as follows: Group A consisted of 13 patients showing 99mTc-sestamibi WR < 22.5%; group B of 11 patients showing 99mTc-sestamibi WR ≥ 22.5%. Significant correlations were observed between 99mTc-sestamibi WR and percentage changes in pressure half-time (T1/2), as well as those in the maximum first derivative LV pressure (LV dP/dtmax)(r = .43, P = .033; r =-.63, P = .001). The percentage changes in LV dP/dtmax and those in T1/2 were significantly more reduced in group B than in group A (P < .05). The biphasic force-frequency relation was more frequently observed in group B than in group A (82% vs. 18%). Conclusion. Increased 99mTc-sestamibi washout is associated with an impaired contractile reserve and prolonged relaxation, suggesting that myocardial 99mTc-sestamibi scintigraphy may be useful in noninvasively detecting the early impairment of myocardial function in HCM patients.
All Science Journal Classification (ASJC) codes
- Radiology Nuclear Medicine and imaging
- Cardiology and Cardiovascular Medicine