Related Experiment Video
Updated: Jul 24, 2026

Isolation of Atrial Myocytes from Adult Mice
Published on: July 25, 2019
Effect of site, summation and asynchronism of inputs on atrioventricular nodal conduction and refractoriness
J Sanchis1, F J Chorro, L Such
1Servei de Cardiologia, Hospital Clinic i Universitari, València, Spain.
Abstract:
The impulses coming from the sinus node synchronically penetrate the AV node via the crista terminalis and inter-atrial septum. Studies in superfused rabbit AV preparations suggest that the crista terminalis is a more effective input than the inter-atrial septum, and that the summation of both inputs facilitates AV nodal conduction. The aim of this study was to verify the hypothesis in a more physiological model, such as the whole rabbit heart perfused by a Langendorff system. Fifteen rabbit hearts were studied in a Langendorff perfusion system with six bipolar extracellular electrodes: two for stimulating (crista terminalis and inter-atrial septum) and four for recording (crista terminalis, inter-atrial septum, His bundle electrogram and right ventricle). Seven hearts (Group I) were consecutively paced at the crista terminalis, inter-atrial septum and both sites simultaneously, to determine the AV nodal Wenckebach cycle length and effective refractory period under basal conditions and after acetylcholine (0.75 x 10(-6) M). In eight hearts under 0.75 x 10(-6) M acetylcholine (Group II), the crista terminalis and inter-atrial septum were simultaneously (delay = 0 ms) or sequentially (delay = 2, 4, 6, 8, 10, 12, 14, and 16 ms) stimulated to calculate the AV nodal effective refractory period and the AH interval at an atrial coupling interval 5 ms longer than the AV nodal effective refractory period, for each delay tested.(ABSTRACT TRUNCATED AT 250 WORDS)
Related Concept Videos
Electrophysiology of Normal Cardiac Rhythm
Mechanism of Cardiac Arrhythmias
Conduction System of the Heart
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
Conduction System of the Heart
This system relies on the unique properties of nodal and Purkinje cells:...
Cardiac Action Potential
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
Dysrhythmias IV: Characteristics of Bradyarrhythmias

