High heart rate associated early repolarization causes J-waves in both zebra finch and mouse.

ABSTRACT: High heart rates are a feature of small endothermic-or warm-blooded-mammals and birds. In small mammals, the QT interval is short, and local ventricular recordings reveal early repolarization that coincides with the J-wave on the ECG, a positive deflection following the QRS complex. Early repolarization contributes to short QT-intervals thereby enabling brief cardiac cycles and high heart rates. We therefore hypothesized high hearts rates associate with early repolarization and J-waves on the ECG of endothermic birds. We tested this hypothesis by comparing isolated hearts of zebra finches and mice and recorded pseudo-ECGs and optical action potentials (zebra finch, n = 8; mouse, n = 8). In both species, heart rate exceeded 300 beats per min, and total ventricular activation was fast (QRS <

SUBMITTER: Offerhaus JA 

PROVIDER: S-EPMC7953022 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature