Key result
Avian dominant pacemaker localizes to vena cava valve bases and spans more extensively than mammalian.
Why the study?
The exact location and electrophysiological characteristics of the dominant pacemaker site in the adult bird heart remain ill-defined.
Reveals the anatomical location and electrical properties of the dominant pacemaker in adult chickens, suggesting an anatomically broader cardiac conduction site than in mammals.
The exact location of the dominant pacemaker site in adult bird heart continues to be ill-defined. The aim of this study was to identify the localization of the dominant pacemaker and to investigate its electrophysiological characteristics in isolated sinoatrial preparations of the adult chicken (Gallus gallus domesticus) heart. The dominant pacemaker was localized at the base of the right leaflet of the valve of the right cranial vena cava and at the base of both leaflets of the valve of the caudal vena cava. But latent pacemakers were also identified in regions around these valves. Additionally, the valve leaflets generated conducting-like APs that with high amplitude, fast maximal upstroke velocity (greater than in working myocardium) and with diastolic depolarization. The avian sinoatrial junction is electrophysiologically heterogeneous. The avian dominant pacemaker site is more extensive than that in mammals. These findings establish a foundation for understanding species-specific pacemaker mechanisms and their evolution.
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Lebedeva et al. (2026) studied Basic cardiac electrophysiology. Electrophysiological mapping was evaluated on Localization and electrophysiological characterization of the dominant pacemaker. Electrophysiological mapping identified that the avian dominant pacemaker site is located at the base of the vena cava valves and is more extensive than that in mammals.
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