Related Experiment Video
Updated: Jul 3, 2026

Confirmation of Myocardial Ischemia and Reperfusion Injury in Mice Using Surface Pad Electrocardiography
Published on: November 24, 2016
Effect of acute subendocardial ischemia on ventricular refractory periods
1Department of Cardiology, Liaocheng City People's Hospital, Shandong Province, People's Republic of China.
Objectives:
To investigate the impact of acute subendocardial ischemia on the dispersion of ventricular refractory periods.
Methods:
Acute subendocardial ischemia was induced in sheep by partial ligation of the left circumflex coronary artery and rapid pacing of the left atrium. The ventricular effective refractory period (ERP) was measured in five areas of the left ventricle by a programmed premature stimulation technique.
Results:
The average ERP and ERP dispersion remained unchanged in the control group (n=5, P>0.05). In the study group (n=5), the ERP was shortened following subendocardial ischemia. ERP dispersion decreased significantly from 48+/-9 ms to 36+/-13 ms 30 min after the ischemia (P=0.02). There was neither spontaneous nor stimulation-induced ventricular arrhythmia after ischemia.
Conclusion:
Acute subendocardial ischemia leads to a homogenous reduction of ventricular ERP. This may partially explain why subendocardial ischemia is associated with a low incidence of ventricular arrhythmia.
Related Concept Videos
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
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers
Verapamil, a calcium channel blocker, inhibits calcium movement across myocardial cell membranes and vascular smooth muscle. This results in the dilation of coronary and...
Dysrhythmias IV: Characteristics of Bradyarrhythmias

