[The association of coronary slow flow with time to peak systolic strain]

Tissue deformation time is an important factor in regional myocardial contractile functions. The aim of this study was to evaluate the association of coronary slow flow (CSF) with time to peak systolic strain.

The study included 25 patients (23 men, 2 women; mean age 48.4±11.9 years) who were found to have CSF on coronary angiography and 20 healthy controls (16 men, 4 women; mean age 51±11.3 years) with normal coronary angiograms. Coronary slow flow was determined using the TIMI frame count (TFC) method. Echocardiographic recordings were obtained from standard apical and parasternal views. Color Doppler myocardial images were acquired at 160-200/sec frame rates. Time to peak systolic strain was measured from the basal, mid, and apical segments of all left ventricular walls.

There were no significant differences between the patients and controls with respect to left ventricular systolic functions (ejection fraction 67±5% vs. 66±4%). TIMI frame counts were greater in the CSF group compared to the controls (left anterior descending artery 42.8±7.7 vs. 17.9±3.5; circumflex artery 37.7±6.5 vs. 16.6±2.9; right coronary artery 41.2±6.4 vs. 17.3±2.7, respectively; p<0.001). All peak systolic strain values measured at 18 segments of the left ventricle walls on color Doppler myocardial images were significantly higher in the CSF group compared to the controls (p<0.001). In both groups, the mean peak systolic strain values obtained in the same walls were shorter in the mid segments compared with basal segments (p<0.05), but mid and apical segments did not differ significantly in this respect (p>0.05).

Our study is the first to demonstrate prolonged peak systolic strain times in CSF. This prolongation might be used as a predictor for the deterioration of regional myocardial contractile functions in CSF patients.