Structural and Functional Properties of Subsidiary Atrial Pacemakers in a Goat Model of Sinus Node Disease

Soattin, Luca; Borbas, Zoltan; Caldwell, Jane C.; Prendergast, Brian; Vohra, Akbar; Saeed, Yawer; Hoschtitzky, Andreas; Yanni, Joseph; Atkinson, Andrew; Logantha, Sunil Jit R. J.; Borbas, Balint; Garratt, Clifford J.; Morris, Gwilym M.; Dobrzynski, Halina

doi:10.3389/fphys.2021.592229

Cited by 9 publications

(2 citation statements)

References 88 publications

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“…Studies of experimental animals, using immunohistohemical techniques, have demonstrated the presence of a paranodal area within the terminal crest 25. More recent studies have confirmed the significance of this area in the goat 26. In the serially sectioned histological datasets at our disposal from human hearts, we are able to distinguish the paranodal area using the criteria of Aschoff and Mönckeberg in around one-third of cases.…”

Section: The Criteria For Recognition Of the Components Of The Conduc...mentioning

confidence: 70%

Anatomy of the conduction tissues 100 years on: what have we learned?

Sánchez‐Quintana

Anderson

Tretter

et al. 2021

Heart

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Knowledge of the anatomy of the ‘conduction tissues’ of the heart is a 20th century phenomenon. Although controversies still continue on the topic, most could have been avoided had greater attention been paid to the original descriptions. All cardiomyocytes, of course, have the capacity to conduct the cardiac impulse. The tissues specifically described as ‘conducting’ first generate the cardiac impulse, and then deliver it in such a fashion that the ventricles contract in orderly fashion. The tissues cannot readily be distinguished by gross inspection. Robust definitions for their recognition had been provided by the end of the first decade of the 20th century. These definitions retain their currency. The sinus node lies as a cigar-shaped structure subepicardially within the terminal groove. There is evidence that it is associated with a paranodal area that may have functional significance. Suggestions of dual nodes, however, are without histological confirmation. The atrioventricular node is located within the triangle of Koch, with significant inferior extensions occupying the atrial vestibules and with septal connections. The conduction axis penetrates the insulating plane of the atrioventricular junctions to continue as the ventricular pathways. Remnants of a ring of cardiomyocytes observed during development are also to be found within the atrial vestibules, particularly a prominent retroaortic remnant, although that their role has still to be determined. Application of the initial criteria for nodes and tracts shows that there are no special ‘conducting tissues’ in the pulmonary venous sleeves that might underscore the abnormal rhythm of atrial fibrillation.

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Section: The Criteria For Recognition Of the Components Of The Conduc...mentioning

confidence: 70%

Anatomy of the conduction tissues 100 years on: what have we learned?

Sánchez‐Quintana

Anderson

Tretter

et al. 2021

Heart

View full text Add to dashboard Cite

show abstract

“…This difference in the architecture of the microvasculature is also paralleled by the differential anatomy of autonomic inputs. 14 There is evidence that in humans 15–17 and goats, 18 the SAN is surrounded by an extensive paranodal area with properties of both nodal and atrial tissues. This paranodal area has been proposed to adopt a role in pacemaking, which could explain the widespread distribution of the leading pacemaker site (wandering pacemaker) in the human right atrium as observed in clinics.…”

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confidence: 99%

Pacemaker Channels and the Chronotropic Response in Health and Disease

Hennis,

Piantoni,

Biel

et al. 2024

Circulation Research

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Loss or dysregulation of the normally precise control of heart rate via the autonomic nervous system plays a critical role during the development and progression of cardiovascular disease—including ischemic heart disease, heart failure, and arrhythmias. While the clinical significance of regulating changes in heart rate, known as the chronotropic effect, is undeniable, the mechanisms controlling these changes remain not fully understood. Heart rate acceleration and deceleration are mediated by increasing or decreasing the spontaneous firing rate of pacemaker cells in the sinoatrial node. During the transition from rest to activity, sympathetic neurons stimulate these cells by activating β-adrenergic receptors and increasing intracellular cyclic adenosine monophosphate. The same signal transduction pathway is targeted by positive chronotropic drugs such as norepinephrine and dobutamine, which are used in the treatment of cardiogenic shock and severe heart failure. The cyclic adenosine monophosphate–sensitive hyperpolarization–activated current (I f ) in pacemaker cells is passed by hyperpolarization-activated cyclic nucleotide-gated cation channels and is critical for generating the autonomous heartbeat. In addition, this current has been suggested to play a central role in the chronotropic effect. Recent studies demonstrate that cyclic adenosine monophosphate–dependent regulation of HCN4 (hyperpolarization-activated cyclic nucleotide-gated cation channel isoform 4) acts to stabilize the heart rate, particularly during rapid rate transitions induced by the autonomic nervous system. The mechanism is based on creating a balance between firing and recently discovered nonfiring pacemaker cells in the sinoatrial node. In this way, hyperpolarization-activated cyclic nucleotide-gated cation channels may protect the heart from sinoatrial node dysfunction, secondary arrhythmia of the atria, and potentially fatal tachyarrhythmia of the ventricles. Here, we review the latest findings on sinoatrial node automaticity and discuss the physiological and pathophysiological role of HCN pacemaker channels in the chronotropic response and beyond.

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Anatomical features for an adequate choice of the experimental animal model in biomedicine: III. Ferret, goat, sheep, and horse

Lossi¹

2022

Annals of Anatomy - Anatomischer Anzeiger

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Structural and Functional Properties of Subsidiary Atrial Pacemakers in a Goat Model of Sinus Node Disease

Cited by 9 publications

References 88 publications

Anatomy of the conduction tissues 100 years on: what have we learned?

Anatomy of the conduction tissues 100 years on: what have we learned?

Pacemaker Channels and the Chronotropic Response in Health and Disease

Anatomical features for an adequate choice of the experimental animal model in biomedicine: III. Ferret, goat, sheep, and horse

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