Effects of ageing on pro-arrhythmic ventricular phenotypes in incrementally paced murine Pgc-1 β (-/-) hearts.

Effects of ageing on pro-arrhythmic ventricular phenotypes in incrementally paced murine Pgc-1β (-/-) hearts. Pflugers Arch. 2017 Aug 18;: Authors: Ahmad S, Valli H, Edling CE, Grace AA, Jeevaratnam K, Huang CL Abstract A range of chronic clinical conditions accompany cardiomyocyte energetic dysfunction and constitute independent risk factors for cardiac arrhythmia. We investigated pro-arrhythmic and arrhythmic phenotypes in energetically deficient C57BL mice with genetic ablation of the mitochondrial promoter peroxisome proliferator-activated receptor-γ coactivator-1β (Pgc-1β), a known model of ventricular arrhythmia. Pro-arrhythmic and cellular action potential (AP) characteristics were compared in intact Langendorff-perfused hearts from young (12-16 week) and aged (> 52 week), wild-type (WT) and Pgc-1β (-/-) mice. Simultaneous electrocardiographic and intracellular microelectrode recordings were made through successive trains of 100 regular stimuli at progressively incremented heart rates. Aged Pgc-1β (-/-) hearts displayed an increased incidence of arrhythmia compared to other groups. Young and aged Pgc-1β (-/-) hearts showed higher incidences of alternans in both AP activation (maximum AP upshoot velocity (dV/dt)max and latency), recovery (action potential duration (APD90) and resting membrane potential (RMP) characteristics compared to WT hearts. This was particularly apparent at lower pacing frequencies. These fin...
Source: Pflugers Archiv : European Journal of Physiology - Category: Physiology Authors: Tags: Pflugers Arch Source Type: research