Related Experiment Video
Updated: Sep 17, 2025
Rat Model of Right-Sided Cardiac Remodeling and Arrhythmia Using Pulmonary Artery Banding
Published on: August 30, 2024
Atrial depolarization electrocardiographic features during orthodromic atrioventricular reciprocating tachycardia
A Maffei1, M Perego1, D Cavallini2
1Clinica Veterinaria Malpensa, Anicura, Via Marconi, 27, 21017 Samarate, Varese, Italy.
Introduction/Objectives:
Electrocardiographic features of atrial depolarization (AD) during orthodromic atrioventricular reciprocating tachycardia (OAVRT) have been widely studied to localize accessory pathways (APs) in humans. The aim of this study was to determine whether AD characteristics might also be used to determine AP anatomical sites in dogs.
Animals, Materials And Methods:
Clinical records of 83 dogs that underwent electrophysiologic studies for AP ablation were retrospectively analyzed. Accessory pathways were classified into three groups according to localization: right anterior (RA, 13.3%), right postero-septal (RPS, 36.1%), and right posterior (RP, 50.6%). Electrocardiographic characteristics of AD (duration, amplitude, and axis) and OAVRT (AD-AD, peak of R wave - atrial depolarization (R-AD)/atrial depolarization - peak of R wave (AD-R), peak to peak of R wave (RR) interval, and QT duration) were analyzed in all 12 leads.
Results:
Mean AD duration in RA, RPS, and RP was 48.0 ± 10.3 ms, 46.1 ± 10.6 ms, and 47.1 ± 10.2 ms, respectively, and the mean amplitude was -0.25 ± 0.12 mV, -0.28 ± 0.20 mV, and -0.28 ± 0.18 mV, respectively. The median electrical axis on the frontal plane was -90.0° (interquartile range [IQR]: 26.5° in RA, 9.4° in RPS, and 13.9° in RP). The median AD-R, mean R-AD intervals, and mean R-AD/AD-R were 140.0 ms (IQR: 34.5 ms), 72.0 ± 19.3 ms, and 0.50 ± 0.14 in RA; 138.0 ms (IQR: 33.0 ms), 76.5 ± 13.6 ms, and 0.55 ± 0.15 in RPS; and 121.0 ms (IQR: 20.0 ms), 74.1 ± 11.7 ms, and 0.59 ± 0.15 in RP. No other statistically significant differences in electrocardiographic parameters were found.
Study Limitations:
Identification of ADs in some dogs was not straightforward, and thoracic conformation differences may have affected AD measurements.
Conclusions:
Electrocardiographic features of AD during OAVRT are not useful for localizing right-sided APs in dogs.
Related Concept Videos
01:30Cardiac 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
01:25Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
01:29Dysrhythmias III: Characteristics of Dysrhythmias
01:19Electrophysiology of Normal Cardiac Rhythm
01:18Dysrhythmias IV: Characteristics of Bradyarrhythmias
01:13The Cardiac Cycle
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and...