Left ventricular function in patients with coronary slow flow: a tissue Doppler study

OBJECTIVES
This study, was designed to assess left ventricular systolic and diastolic functions with conventional and tissue Doppler echocardiography in patients with the coronary slow flow phenomenon (CSFP).

STUDY DESIGN
The study included 22 patients (12 males, 10 females; mean age 48±12 years) with angiographically diagnosed CSFP but with otherwise normal epicardial coronary arteries. Twenty-two subjects (14 males, 8 females; mean age 47±11 years) with angiographically normal coronary arteries constituted the control group. Left ventricular systolic and diastolic functions were assessed by conventional and tissue-Doppler echocardiography before angiography. The diagnosis of CSFP was made using the TIMI frame count (TFC) method. TIMI frame counts were determined for the left anterior descending (LAD), circumflex (Cx), and right coronary (RCA) arteries.

RESULTS
Patients with CSFP had significantly higher values of corrected TFC for the LAD, TFC for Cx and RCA, and the mean TFC (p<0.001). There were no significant differences in ejection fraction and mitral annular peak systolic velocity between the two groups. Conventional echocardiography showed significantly lower maximal velocity of early diastolic filling (E), ratio of maximal early to late diastolic filling (E/A), and longer isovolumetric relaxation time (IVRT) in the patient group (p<0.01, p<0.001, and p=0.001, respectively). Maximal velocity of atrial diastolic filling (A) and deceleration time of early diastolic filling (DT) were similar. Among tissue Doppler parameters, Em and Em/Am were significantly lower (p<0.001); IVRTm (p=0.001) and DTm (p=0.02) were significantly higher in the patient group. TIMI frame counts were negatively correlated with E, E/A, Em, and Em/Am, and positively correlated with DT, IVRT, DTm, IVRTm, and E/Em.

CONCLUSION
Coronary slow flow phenomenon is associated with left ventricular diastolic and systolic dysfunctions, requiring a close follow-up in this patient group.