Coronary hemodynamics in left ventricular hypertrophy, as evidenced by<sup>13</sup>N-ammonium positron emission tomography

Abstract

In patients with left ventricular hypertrophv (LVH), coronary hemodynamics was studied by 13 N-ammonium positron emission tomography (PET). We examined 38 patients aged 53,22±9,57 years, who had LVH in the presence of hypertensive disease. A control group comprised 15 individuals without a history of cardiovascular diseases The structural and functional parameters on the left ventricle were determined by echocadiography. Myocardial blood flow (МBР) was evaluated at rest and during a dipyridamole test, by using PET. The coronагу reserve (CR) and resistanсe were calculated. In the patients with LVH and in the controls, the mean resting values of MBF did not differ significantly (73,3±12,8 versus 73,4±16,6 ml/min per 100 g of tissue, the differences wen insignificant). During the dipyridamole test, the values of MBF and CR were significantly lower in the patients with LVH (140,4±35,1 versus 219,86±69,2 ml/min per 100 g of tissue (p<0,5) and (1,94±0,62 versus 2,95±0,41 (p<0,05), respectively). In the presence of vasodilatation, coronary resistance was substantially less in the control group (0,54±0,16 versus 0,89±0,24; p<0,05). There was no correlation between the coronary hemodynamic parameters and the left ventricular myocardial mass index. CR was substantially less in the concentric type of LVH than that in the eccentric type (1,77±0,44 versus 2,11±0,51; p<0,05). All patients with concentric LVH showed impaired left ventricular diastolic function (LVDF) whereas the latter was observed only in case in the eccentric type. In LVH, resting МBF did not virtually differ from the normal values; however, the coronary bed responded to dipyridamole-induced vasodilatation to a substantially lesser degree. The decrease in CR was largely marked in concentric hypertrophy and associated with LVDF.