Related Experiment Video
Updated: Aug 16, 2026

Tachycardia-Induced Cardiomyopathy As a Chronic Heart Failure Model in Swine
Published on: February 17, 2018
Mechanism for atrial tachyarrhythmia in chronic volume overload-induced dilated atria
Masamichi Hirose1, Yasuchika Takeishi, Takuya Miyamoto
1Department of Molecular Pharmacology, Shinshu University School of Medicine, Nagano, Japan. hirose@sch.md.shinshu-u.ac.jp
Unlabelled:
Mechanism of chronic volume overload-induced AT.
Introduction:
Atrial dilatation associated with chronic volume overload (CVO) plays an important role in the development of atrial fibrillation (AF). However, the underlying mechanisms are unknown.
Methods And Results:
CVO-induced atrial dilatation was created in Japanese white rabbits using arteriovenous shunt formation for 6 weeks. Epicardial action potentials were measured from both atria in Langendorff-perfused sham-operated control hearts (n=8) and in CVO hearts (n=8) using high-resolution optical mapping techniques. The left atrial diameter was greater in CVO hearts (16.0+/-0.4 mm) compared to control hearts (11.0+/-0.8 mm). During steady-state pacing, right and left atrial conduction velocities were significantly lower in CVO hearts compared to control hearts (P<0.01). Rapid atrial pacing did not induce atrial tachyarrhythmia (AT) in any control hearts. However, in seven of eight CVO hearts 16 episodes of AT were induced, of which 9 exhibited a single reentrant circuit. The remaining 7 episodes exhibited a focal pattern of excitation without evidence of reentry. Interestingly, the activation rate was higher during reentry (16.1+/-1.5 Hz) compared to focal AT (9.8+/-1.0 Hz). In addition, 15 of 16 episodes occurred in the posterior left atrium (PLA). In all seven CVO hearts, AT was self-sustained for more than 10 minutes.
Conclusion:
CVO caused atrial dilatation, conduction slowing, and AT associated with reentrant and focal excitation originating from the PLA. These results suggest that the PLA may play an important role in AT induction associated with CVO-induced atrial dilation.
Related Concept Videos
Mechanism of Cardiac Arrhythmias
Heart Failure II: Pathophysiology
Imbalances in Cardiac Output
CHF can occur due to the failure of either side of the heart. Left-side failure leads to pulmonary congestion—the right side continues to send blood...
Mitral Regurgitation I: Introduction
Dysrhythmias II: Classification of Tachyarrhythmias
Aortic Regurgitation I: Introduction
