Relationship of mechanical and electrical dispersion and coronary artery disease in patients on renal replacement therapy

Abstract

Abstract Introduction: Since coronary artery disease (CAD) is the leading cause of death in patients on renal replacement therapy (RRT), detection of asymptomatic CAD before the impairment of left ventricular (LV) systolic function is of great clinical importance. Aim To investigate the relationship between electrical and mechanical dispersion and CAD in angina free RRT patients with preserved LV ejection fraction (LVEF). Material and methods A total of 78 patients (mean age 59 ± 13 years, 54% male), with LVEF ≥ 50% were included in this prospective study. Electrical dispersion was defined as the difference between the longest and shortest corrected QT interval. The duration of mechanical contraction was determined by myocardial strain analysis. Mechanical dispersion was defined as the standard deviation of mechanical contraction durations of all LV segments (MD_SD) or the difference between the longest and shortest duration of mechanical contraction (MD_delta). A coronary calcium score using cardiac computed tomography was assessed in a subgroup of 20 patients without known CAD. Results Documented CAD was present in 14% of study patients. There was no significant correlation between electrical and mechanical dispersion (p > 0.05). In contrast to electrical dispersion, mechanical dispersion was independently associated with CAD (odds ratio 1.05, 95% confidence interval 1.01–1.09, p = 0.010). In patients without documented CAD, MD_delta was strongly correlated with total coronary calcium score (r = 0.57; p = 0.01), while QTc dispersion was not. Conclusion Electrical and mechanical dispersion are not correlated in dialysis patients. Unlike electrical dispersion, mechanical dispersion is associated with both documented CAD and silent coronary atherosclerosis in patients with end stage renal failure on RRT.