Reconstituted High-Density Lipoprotein Shortens Cardiac Repolarization

Objectives We hypothesize that increasing high-density lipoprotein cholesterol (HDL-C) shortens cardiac repolarization. Background HDL-C is inversely associated with sudden death. The relation between HDL-C and repolarization of the heart is unexplored. Methods HDL-C was elevated with reconstituted high-density lipoprotein (rHDL). Cardiac repolarization was studied by recording cardiac transmembrane potentials with the patch clamp technique from isolated rabbit cardiomyocytes that were superfused with rHDL. Infusions with rHDL (40 mg/kg body weight) were performed in dyslipidemic patients and healthy volunteers. Electrocardiograms were recorded to assess cardiac repolarization before and 24 h after infusion with rHDL. Results rHDL as well as purified human apolipoprotein AI shortened repolarization of isolated rabbit cardiomyocytes by similar to 25% (p <0.05). rHDL infusion shortened the heart rate-corrected QT interval on surface electrocardiograms in all participants (p <0.001). Conclusions rHDL shortens cardiac repolarization. These data provide evidence for a novel mechanism of HDL infusion that may contribute to reduction of sudden cardiac death. (J Am Coll Cardiol 2011;58:40-4) (C) 2011 by the American College of Cardiology Foundation