Coronary flow, VO2 peak and anaerobic threshold in patients with dilated cardiomyopathy

Background Coronary flow is influenced by several determinants and may change according to external stimuli. In patients with dilated cardiomyopathy (DC), adaptive mechanisms could induce alterations in coronary flow, possibly related to oxygen consumption. Methods In 67 consecutive patients with DC (mean age 52.06 ± 13.84, 52 male gender, left ventricle ejection fraction (LVEF) 29.49% ± 8.68) and normal coronary angiography findings, coronary flow in left anterior descending (LAD), right coronary artery (RC) and left circumflex (LCx) was reported as TIMI frame count (TFC). All patients underwent a cardiopulmonary test with VO2 peak and anaerobic threshold (AT) measurement, New York Heart Association (NYHA) class stratification, two-dimensional echocardiographic evaluation including LVEF and left ventricle end-diastolic diameter (LVEDD) assessment. All patients were receiving optimal medical treatment. Results In a multivariate analysis, a statistically significant correlation was found between VO2 peak and TFC (B 7.61, p < 0.001, R2 0.61 for LAD; B 3.42, p < 0.001, R2 0.33 for RC); an inverse correlation was found between AT and TFC (B − 9.77, p < 0.001, R2 0.61 for LAD; B − 4.26, p < 0.001, R2 0.33 for RC). Conclusions Coronary flow is related to VO2 peak and AT in patients with DC, suggesting a “compensatory” mechanism.