Right ventricular functions in patients with slow coronary flow.

Objective: The objective of this study was to evaluate right ventricular systolic and diastolic functions with the use of conventional and tissue Doppler echocardiography in patients with slow coronary flow (SCF).
Methods and Results: Patients who were detected to have SCF but otherwise normal epicardial coronary arteries between October 2010 and July 2011 were included in our study. The control group was selected from the patients with normal coronary arteries but no SCF. All patients underwent echocardiography to evaluate left and right cardiac functions with conventional methods and tissue Doppler imaging. The study consisted of 86 patients [59 (68.6%) males, mean age: 54 +/- 10 years) with SCF. Sixty-six subjects [42 (63.6%) males, mean age: 55 +/- 8 years] with normal coronary arteries without SCF constituted the control group.Tissue Doppler findings of left ventricular systolic and diastolic functions were significantly disturbed in the SCF group (myocardial performance index: 0.37+/- 0.02 vs. 0.28 +/- 0.02, P<0.001; E/A ratio: 0.9 +/-0.1 vs. 1.1 0.1, P < 0.001). However, when the right ventricular functions were considered, no significant difference was observed between the 2 groups (myocardial performance index: 0.25 +/- 0.10 vs. 0.25 +/- 0.10, P = 0.9; E/A ratio: 0.50 +/- 0.06 vs. 0.50 +/- 0.08, P= 0.3; TAPSE: 26.2 +/- 2.2 vs. 25.9 +/- 2.2, P = 0.6).
Conclusions: Preserved right ventricular diastolic and systolic functions in contrast to the impaired left ventricular functions in patients with SCF was the main finding of our study. The exact mechanisms of this new finding should be investigated by further studies.