Vectorcardiographic QRS area as a predictor of response to cardiac resynchronization therapy

Cardiac resynchronization therapy(CRT)is a good treatment for heart failure accompanied by ventricular conduction abnormalities.Current ECG criteria in international guidelines seem to be suboptimal to select heart failure patients for CRT.The criteria QRS duration and left bundle branch block(LBBB)QRS morphology insufficiently detect left ventricular activation delay,which is required for benefit from CRT.Additionally,there are various definitions for LBBB,in which each one has a different association with CRT benefit and is prone to subjective interpretation.Recent studies have shown that the objectively measured vectorcardiographic QRS area identifies left ventricular activation delay with higher accuracy than any of the current ECG criteria.Indeed,various studies have consistently shown that a high QRS area prior to CRT predicts both echocardiographic and clinical improvement after CRT.The beneficial relation of QRS area with CRT-outcome was largely independent from QRS morphology,QRS duration,and patient characteristics known to affect CRT-outcome including ischemic etiology and sex.On top of QRS area prior to CRT,the reduction in QRS area after CRT further improves benefit.QRS area is easily obtainable from a standard 12-lead ECG though it currently requires off-line analysis.Clinical applicability will be significantly improved when QRS area is automatically determined by ECG equipment.

Hemolysis results in impaired intestinal microcirculation and intestinal epithelial cell injury

AIM:To study the effect of circulating cell-free oxy-hemoglobin(FHb) on intestinal microcirculation and intestinal epithelial injury in a rat model. METHODS:To induce elevated intravascular circulating FHb,male Sprague-Dawley rats received water or FHb infusion.Microcirculatory changes in jejunum,ileum and colon were evaluated using fluorescent microspheres.Intestinal injury was quantified as plasmatic release of ileal lipid binding protein(iLBP) and verified by histological analysis of the ileum. RESULTS:Water and FHb infusions resulted,when compared with saline infusion,in reduced intestinal microcirculation(after 30 min P<0.05,or better;after 60 min FHb infusion P<0.05 for jejunum and colon) .Circulating FHb levels correlated significantly with release of iLBP(Spearman r=0.72,P=0.0011) .Epithelial cell injury of the villi was histologically observed after water and FHb infusions. CONCLUSION:This study shows that circulating FHb leads to a reduction in intestinal microcirculatory blood flow with marked injury to intestinal epithelial cells. These data support the hypothesis that circulating FHb contributes to the development of intestinal injury.