Assessment of coronary blood flow in non-ischemic dilated cardiomyopathy with the TIMI frame count method

Objective: We aimed to evaluate coronary blood flow by means of the TIMI (Thrombolysis in Myocardial Infarction) frame count in patients with idiopathic dilated cardiomyopathy who had angiographically proven normal coronary arteries and compare the results with those of healthy subjects. Methods: This retrospective study included 62 patients with idiopathic dilated cardiomyopathy (34 men, 28 women; mean age 59.7±10.6 years) and 62 control subjects without dilated cardiomyopathy (28 men, 34 women; mean age 56.6±9.8 years). All patients and control subjects had angiographically proven normal coronary arteries. Dilated cardiomyopathy patients had a left ventricular ejection fraction 45%. The TIMI frame count was determined for each major coronary artery in each patient. Statistical analysis was performed using Student’s t test, Chi-square test and Pearson correlation analysis. Results: The TIMI frame counts for each major epicardial coronary artery were found to be significantly higher in patients with idiopathic dilated cardiomyopathy compared to control subjects (corrected TIMI frame count for left anterior descending coronary artery: 37.0±12.5 vs 28.7±11.6, respectively, p 0.001; left circumflex coronary artery: 37.7±12.1 vs 31.0±12.5, respectively, p=0.003; right coronary artery: 37.4±12.6 vs 30.7±11.6, respectively, p=0.003). Mean TIMI frame count had significant although weak positive correlation with left ventricular end-diastolic diameter (r=0.350, p 0.001) and left ventricular end-systolic diameter (r=0.358, p 0.001). Conclusion: We have shown that patients with idiopathic dilated cardiomyopathy and angiographically normal coronary arteries have higher TIMI frame counts for all three coronary vessels, indicating impaired coronary blood flow, compared to control subjects without dilated car- diomyopathy.