| Abstract: | Background and hypothesis: To investigate the mechanism of regional left ventricular diastolic filling disturbance in hypertrophic cardiomyopathy (HCM), we assessed the relationship between abnormalities of regional ventricular rapid filling and regional coronary microcirculation using radionuclide ventriculography and exercise 201thallium (201Tl) myocardial scintigraphy with sector analysis. Methods: Thirty patients with HCM and 14 patients with atypical chest pain syndrome (controls) were studied. Left ventricular images (left anterior oblique view) were obtained by electrocardiogram-gated 99mtechnetium radionuclide an-giography and were divided into three sectors radiating from the geometric center. The time-activity curves and their first derivative curves were analyzed, and the peak filling rate (PFR), the ratio of the time-to-peak filling rate per diastolic interval (TPFR/T) were calculated for the global left ventricle and for the lateral and septal sectors. Exercise stress 201Tl myocardial scintigraphy was also performed, and early and delayed images were obtained. The regional washout rate (WR) was then evaluated for the lateral and septal sectors. Results: In HCM patients, the regional PFR in the septal sector (corresponding to the region of hypertrophic myocardium) was 285 ± 76%/s, and was significantly lower than that in the controls (398 ± 90%/s, p <0.01). The regional TPFR/T in the septal sector (32 ± 10%) was prolonged compared with the value of 21 ± 5% in the controls (p <0.05). The regional WR in the septal sector was 21 ± 9%, and was significantly lower than that in the controls (43 ± 5%, p <0.01). Moreover, regional WR correlated positively with regional PFR (r = 0.5, p < 0.05) and showed a weak negative relationship with regional TPFR/T (r = -0.4, p <0.07) in the septal sector. Conclusions: These results suggest that regional impairment of rapid filling might be related to a disturbance of the coronary microcirculation in HCM. |
