Functional Properties of Sinocaval Conduction

Ito, Morio; Arita, Makoto; Saeki, Kazuyuki; Tanoue, Mitsuo; Fukushima, Isamu; Yanaga, T; Mashiba, Hiroto

doi:10.2170/jjphysiol.17.174

Cited by 55 publications

(33 citation statements)

References 21 publications

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“…Previous studies have shown that there was conduction block in the SVC. 3,6 We identified multiple ionic currents in SVC cells, which was similar to the nature of cardiac cells or PV cardiomyocytes. 11 Half of the SVC cardiomyocytes have I f and thus have properties similar to those of PV or atrial cardiomyocytes.…”

Section: Ap Configurations and Ionic Currents Of Svc Cardiomyocytesmentioning

confidence: 75%

“…6 The presence of cardiomyocytes with pacemaker activity suggests that automaticity may play a role in the arrhythmogenic activity of the SVC. The presence of DAD in SVC cardiomyocytes also suggests that triggered activity has a role in SVC electrical activity.…”

Section: Ap Configurations and Ionic Currents Of Svc Cardiomyocytesmentioning

confidence: 99%

“…5,8 Through multiple cellular electrophysiological studies, the SVC was found to have cardiomyocytes with fast response action potential 7 or with phase 4 depolarization accompanied by the initiation of automatic activity. 6 Another study also has reported abnormal automaticity and fibrillation induced by aconitine in the musculature of the SVC. 9 The atrial muscle extension into the SVC was shown to be the source of the spontaneous ectopic activity recorded in the SVC.…”

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confidence: 96%

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Electrophysiology and Arrhythmogenic Activity of Single Cardiomyocytes From Canine Superior Vena Cava

Chen

Yeh

et al. 2002

Circulation

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Background-The superior vena cava (SVC) has been proved to be a focal point in the initiation of paroxysmal atrial fibrillation. The autonomic nervous system plays an important role in the genesis of atrial fibrillation. However, the arrhythmogenic potentials of SVC and its responses to autonomic agents are not clear. The purpose of this study was to isolate single SVC cardiomyocytes and to investigate their electrophysiological characteristics, as well as the direct effects of autonomic agents. Methods and Results-Canine SVC cardiomyocytes were isolated by perfusion with digestive enzymes. The action potentials and ionic currents were investigated in single SVC cardiomyocytes using the whole-cell clamp technique. Dissociation of the SVC yielded rod-shaped single cardiomyocytes with (nϭ74, 51%) or without (nϭ71, 49%) pacemaker activities. There were similar densities of inward Ca 2ϩ , delayed rectifier K ϩ , transient inward, inward rectifier K ϩ , and pacemaker currents between SVC cardiomyocytes with and without pacemaker activity. SVC cardiomyocytes with pacemaker activity have, however, greater transient outward currents than those without pacemaker activity. In SVC cardiomyocytes, acetylcholine (5.5 mol/L) abolished the spontaneous activities, but isoproterenol (10 nmol/L), atropine (10 mol/L), and phenylephrine (10 mol/L) accelerated the spontaneous activity and induced the occurrences of early or delayed afterdepolarizations. Conclusions-These findings suggest that SVC cardiomyocytes have distinct action potentials and ionic current profiles that may be responsible for the arrhythmogenic activity of the SVC.

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Section: Ap Configurations and Ionic Currents Of Svc Cardiomyocytesmentioning

confidence: 75%

Section: Ap Configurations and Ionic Currents Of Svc Cardiomyocytesmentioning

confidence: 99%

mentioning

confidence: 96%

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Electrophysiology and Arrhythmogenic Activity of Single Cardiomyocytes From Canine Superior Vena Cava

Chen

Yeh

et al. 2002

Circulation

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“…There are several reports about the extension of atrial muscle into the SVC 7,8 and its excitability. 9,10 The question of anatomic inputs from the RA to the SVC, however, has not been addressed.…”

Section: Discussionmentioning

confidence: 99%

Electroanatomic Mapping and Catheter Ablation of Breakthroughs From the Right Atrium to the Superior Vena Cava in Patients With Atrial Fibrillation

et al. 2002

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Background-The superior vena cava (SVC) is one of the sources of ectopies that can initiate atrial fibrillation (AF). We investigated by radiofrequency ablation the electrophysiological characteristics of the junction of the right atrium (RA) and the SVC and the feasibility of electrical disconnection of the SVC from the RA. Methods and Results-Sixteen patients with paroxysmal AF after pulmonary vein isolation underwent electroanatomic mapping at the RA-SVC junction during sinus rhythm. Mapping showed sharp potentials (SVC potentials) inside the SVC. Activation spread from the earliest SVC potential (breakthrough) to the rest of the SVC. SVC potentials were found over a large amount of the circumference, suggesting widespread muscle coverage of the SVC. Breakthroughs from the RA to SVC were located anteriorly, laterally, posteriorly, and septally in 3, 4, 10, and 6 patients, respectively. The number of breakthroughs was 1.4Ϯ0.5 per patient. Radiofrequency energy was applied with the end point of electrical disconnection. All breakthroughs were eliminated with 3.1Ϯ1.7 applications per breakthrough without complications. Conclusions-SVC potentials can be recorded inside the SVC. There are specific breakthroughs from the RA to the SVC that can be identified by electroanatomic mapping. The electrical disconnection of the SVC from the RA is feasible.

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“…8 -16 However, only limited data are available on PAF originating from the superior vena cava (SVC) in humans. [12][13][14][17][18][19][20] Therefore, this study was conducted to (1) investigate the electrophysiological features and results of radiofrequency ablation in patients with spontaneous AF initiated by ectopic beats originating in the SVC and (2) compare the characteristics of ectopic foci originating in either the SVC or PVs.…”

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confidence: 99%

Initiation of Atrial Fibrillation by Ectopic Beats Originating From the Superior Vena Cava

Tsai¹,

et al. 2000

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Background-The superior vena cava (SVC) has cardiac musculature extending from the right atrium. However, no previous study in humans has given details regarding the ectopic foci that initiate paroxysmal atrial fibrillation (PAF), which may originate from the SVC. Methods and Results-A total of 130 patients with frequent attacks of PAF initiated by ectopic beats were included. Eight patients (6%) had spontaneous AF initiated by a burst of rapid ectopic beats from the SVC (located 19Ϯ7 mm above the junction of the SVC and right atrium), which was confirmed by multiplane angiographic and intracardiac echocardiographic visualization and was marked by a sharp SVC potential preceding atrial activity. During initial repetitive discharges, the group with SVC ectopy had a higher incidence of intravenous conduction block than the group with pulmonary vein ectopy (75% versus 37%; Pϭ0.03). The activation time of the earliest intracardiac ectopic activities relative to ectopic P wave onset was significantly shorter in the SVC ectopy than the pulmonary vein ectopy group (37Ϯ15 versus 84Ϯ32 ms; PϽ0.001). After 5Ϯ3 applications of radiofrequency energy, AF was eliminated. SVC angiography after ablation revealed a local indentation of the venous wall in one patient. Two patients manifested coexisting sinus rhythm and a "focal" fibrillating activity confined inside the SVC after radiofrequency ablation. During a follow-up period of 9Ϯ3 months, all 8 patients were free of antiarrhythmic drugs, without tachycardia recurrence or symptoms of SVC obstruction. Conclusions-Ectopic beats initiating PAF can originate from the SVC. A radiofrequency current delivered to eliminate these ectopies is a highly effective and safe way to prevent PAF. (Circulation. 2000;102:67-74.)

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Functional Properties of Sinocaval Conduction

Cited by 55 publications

References 21 publications

Electrophysiology and Arrhythmogenic Activity of Single Cardiomyocytes From Canine Superior Vena Cava

Electrophysiology and Arrhythmogenic Activity of Single Cardiomyocytes From Canine Superior Vena Cava

Electroanatomic Mapping and Catheter Ablation of Breakthroughs From the Right Atrium to the Superior Vena Cava in Patients With Atrial Fibrillation

Initiation of Atrial Fibrillation by Ectopic Beats Originating From the Superior Vena Cava

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