Coronary flow reserve and ischemic-like electrocardiogram in patients withsymptomatic mitral valve prolapse

The purpose of the present study was to determine whether coronary microvas cular function is impaired in patients with symptomatic mitral valve prolap se (MVP) and whether ischemia-like EGG, if present, is related to coronary microvascular dysfunction. Twenty chest pain patients with normal coronary angiograms and MVP proven b y echocardiogram were included. Both treadmill exercise test (TET) and coro nary hemodynamic study were done in each patient. Coronary flow reserve (CF R) was determined by measuring coronary sinus flow (CSF) or great cardiac v enous flow (GCVF) both at baseline and after dipyridamole 0.56 mg/kg IV for 4 minutes (maximum). AU patients were divided into 2 groups with either ne gative (TET-) or positive results of TET (TET+). Another 10 subjects with a typical chest pain, normal coronary angiograms, echocardiogram and TET were used as controls. There were no differences in GCVF, either at baseline or after dipyridamole infusion, among the 3 groups. Calculated CFR using GCVF was similar among the 3 groups. However, baseline CSF was higher in the TET+ group (TET- vs T ET+ vs control: 77 +/- 24 vs 96 +/- 31 vs 75 +/- 12 ml/min, p < 0.05) and m aximum CSF was lower in the TET- group (TET- vs TET+ vs control: 167 +/- 25 vs 219 +/- 85 vs 238 +/- 80 ml/min, p < 0.05). Calculated CFR using CSF wa s significantly reduced in both the TET- (2.26 +/- 0.4) and TET+ groups (2. 31 +/- 0.7) as compared with the control subjects (3.18 +/- 0.95, p < 0.01) . There were no differences in any of the hemodynamic parameters between th e TET- and TET+ groups. Coronary microvascular function could be impaired in patients with symptoma tic MVP. Such impairment, when presented, was probably regional and outside the territory of the left anterior descending coronary artery. However, it was irrelevant to the presence of ischemic-like ECC during exercise.