Background: It has been recognized that "cross-talk" occurs between coronary flow and left ventricular (LV) function. This study tested the hypothesis that impairment of coronary flow reserve (CFR) in arterial hypertension is associated with LV systolic and diastolic dysfunction, independent of abnormalities in LV geometry.
Methods: We studied 59 newly diagnosed, never-treated hypertensive patients, using transthoracic Doppler echocardiography including pulsed Tissue Doppler of mitral annulus and CFR on left anterior descending artery (low-dose dipyridamole). The study population was divided into two groups on the basis of age-normalized relative wall thickness (RWTn): 36 patients with normal LV geometry (RWTn < or = 0.41) and 23 patients with LV concentric geometry (RWTn > 0.41).
Results: Patients with LV concentric geometry (RWTn > 0.41) had significantly lower values of midwall shortening (but not of endocardial shortening), longer isovolumic relaxation time (IVRT), lower Tissue Doppler-derived early diastolic velocity (Em), higher ratio of transmitral E velocity to Em, and lower CFR as compared to patients with normal LV geometry (RWTn < or = 0.41). In the whole population, a lower CFR was significantly associated with lower values of midwall shortening and Em, longer IVRT, and higher E/Em ratio. After controlling for heart rate, mean blood pressure, and RWTn, only the relation of CFR with IVRT, Em, and E/Em ratio remained significant.
Conclusions: Reduced midwall mechanics is associated with lower CFR, a relationship that depends on LV concentric geometry. A reduced CFR is associated with both impaired relaxation and increased filling pressure, a relation that is independent of LV geometry and pressure load.