Ventricular repolarization time, location of pacing stimulus and current pulse amplitude conspire to determine arrhythmogenicity in mice.
Acta Physiol (Oxf)
; 219(3): 660-668, 2017 03.
Article
en En
| MEDLINE
| ID: mdl-27459728
ABSTRACT
AIM:
In this study, we investigate the impact of altered action potential durations (APD) on ventricular repolarization time and proarrhythmia in mice with and without genetic deletion of the K+ -channel-interacting protein 2 (KChIP2-/- and WT respectively). Moreover, we examine the interrelationship between the dispersion of repolarization time and current pulse amplitude in provoking ventricular arrhythmia.METHODS:
Intracardiac pacing in anesthetized mice determined refractory periods and proarrhythmia susceptibility. Regional activation time (AT), APD and repolarization time (=AT + APD) were measured in isolated hearts using floating microelectrodes.RESULTS:
Proarrhythmia in WT and KChIP2-/- was not sensitive to changes in refractory periods. Action potentials were longer in KChIP2-/- hearts compared to WT hearts. Isolated WT hearts had large apico-basal dispersion of repolarization time, whereas hearts from KChIP2-/- mice had large left-to-right ventricular dispersion of repolarization time. Pacing from the right ventricle in KChIP2-/- mice in vivo revealed significant lower current pulse amplitudes needed to induce arrhythmias in these mice.CONCLUSION:
Large heterogeneity of repolarization time is proarrhythmic when pacing is delivered from the location of earlier repolarization time. Ventricular repolarization time, location of the pacing stimulus and the amplitude of the stimulating current pulse are critical parameters underlying arrhythmia vulnerability.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Arritmias Cardíacas
/
Potenciales de Acción
/
Ventrículos Cardíacos
Límite:
Animals
Idioma:
En
Revista:
Acta Physiol (Oxf)
Asunto de la revista:
FISIOLOGIA
Año:
2017
Tipo del documento:
Article
País de afiliación:
Dinamarca