Ischemic QRS prolongation as a biomarker of severe myocardial ischemia

•The study contains both data from dogs and human subjects.•We use a novel method for quantifying ischemic severity.•QRS distortion indicates decreased arterial flow in dogs undergoing ACO.•QRS distortion could potentially be used as a biomarker for severe myocardial ischemia.

BackgroundPrevious studies have shown that QRS prolongation is a sign of depressed collateral flow and increased rate of myocardial cell death during coronary occlusion. The aims of this study were to evaluate ischemic QRS prolongation as a biomarker of severe ischemia by establishing the relationship between prolongation and collateral flow experimentally in a dog model, and test if the same pattern of ischemic QRS prolongation occurs in man.MethodsDegree of ischemic QRS prolongation was measured using a novel method in dogs (n = 23) and patients (n = 52) during coronary occlusion for 5 min. Collateral arterial flow was assessed in the dogs.ResultsThere was a significant correlation between QRS prolongation and collateral flow in dogs (r = 0.61, p = 0.008). Magnitude and temporal evolution of prolongation during ischemia were similar for dogs and humans (p = 0.202 and p = 0.911).ConclusionQuantification of ischemic QRS prolongation could potentially be used as a biomarker for severe myocardial ischemia.