Automatic Activity Arising in Cardiac Muscle Sleeves of the Pulmonary Vein

Abstract

Ectopic activity in the pulmonary vein cardiac muscle sleeves can both induce and maintain human atrial fibrillation. A central issue in any study of the pulmonary veins is their difference from the left atrial cardiac muscle. Here, we attempt to summarize the physiological phenomena underlying the occurrence of ectopic electrical activity in animal pulmonary veins. We emphasize that the activation of multiple signaling pathways influencing not only myocyte electrophysiology but also the means of excitation–contraction coupling may be required for the initiation of triggered or automatic activity. We also gather information regarding not only the large-scale structure of cardiac muscle sleeves but also recent studies suggesting that cellular heterogeneity may contribute to the generation of arrythmogenic phenomena and to the distinction between pulmonary vein and left atrial heart muscle.

Atrial Fibrillation and Chronic Coronary Ischemia: A Challenging Vicious Circle

“…The main source of the ectopic beats triggering paroxysmal forms of AF is represented by the muscular sleeves within the pulmonary vein ostia, these foci responding to treatment with radio-frequency ablation [ 11 , 12 , 13 ], but the autonomic nervous system, specifically innervation from ganglionated plexi in the left atrium, play a role in the generation of ectopic foci, known as early and late after depolarizations, and electrical dispersion required for AF [ 14 ]. Moreover, there is also a high prevalence of ganglionated plexi in the posterior surface of the right atrium, and their ablation may be effective in about 70% of patients with vagal paroxysmal AF [ 15 ].…”

Selective Inhibition of Pulmonary Vein Excitability by Constitutively Active GIRK Channels Blockade in Rats

“…Ectopic activities arising from the cardiac sleeves of the human pulmonary vein (PV) are responsible for triggering atrial fibrillation [1]. Over the past few years, numerous studies have been conducted to characterize differences in the physiology of atrial and PV cardiomyocytes in an attempt to understand this phenomena (For review, [2]). In a rat PV-Left atria (LA) preparation, we showed that selective activation of α1-adrenergic receptors resulted in the abolition of electrical conduction within the PV, whereas electrical activity was maintained in the LA of the rat [3].…”

Molecular Pathogenesis of Cardiac Arrhythmia

“…The pulmonary veins are the source of the most frequent arrhythmia: atrial fibrillation. Bredeloux et al have provided a review in this Special Issue on the history and latest findings in pulmonary vein research [ 12 ], and Okamoto et al contributed new insights into the molecular mechanisms of pulmonary vein arrhythmias [ 13 ].…”