Studies on Transmembrane Action Potentials and Mechanical Responses of the Venae Cavae and Atria of the Rabbit

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

doi:10.2170/jjphysiol.16.462

Cited by 20 publications

(3 citation statements)

References 20 publications

(11 reference statements)

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“…This is probably because the sinus horns (caval veins) are activated simultaneously with the atria [28,30,[82][83][84][85], thereby masking the sinus activation by the larger P wave (Figure 2). Interestingly, in rabbit, the sinus horn myocardium activates and contracts in synchrony with the atria and has contractility under the regulation of sympathetic and parasympathetic agonists, like atrial and ventricular myocardium (Figure 2d) [86,87]. In mammals, therefore, the sinus myocardium seems to be atrialized in terms of electrical activity and expression of genes, but not in strictly morphological terms.…”

Section: The Sinus Venosus Is Atrialized In Endothermsmentioning

confidence: 99%

Evolution of the Sinus Venosus from Fish to Human

Jensen

Boukens

Wang

et al. 2014

JCDD

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The sinus venosus, the cardiac chamber upstream of the (right) atrium, is a severely underinvestigated structure. Yet, its myocardium harbors the cardiac pacemaker in all vertebrates. In human, ectopic pacemaking and subsequent pathologies may originate from sinus venosus-derived myocardium surrounding the coronary sinus and the superior caval vein. In ectothermic vertebrates, i.e., fishes, amphibians and reptiles, the sinus venosus aids atrial filling by contracting prior to the atrium (atria). This is facilitated by the sinuatrial delay of approximately the same duration as the atrioventricular delay, which facilitates atrial filling of the ventricles. In mammals, the sinuatrial delay is lost, and the sinus venosus-derived myocardium persists as an extensive myocardial sheet surrounding the caval veins, which is activated in synchrony with the myocardium of the atria. The caval vein myocardium is hardly of significance in the healthy formed heart, but we suggest that the sinus venosus functions as a chamber during development when cardiac output, heart rate, blood pressure and architecture is much more like that of ectothermic vertebrates. The remodeling of the sinus venosus in mammals may be an adaptation associated with the high heart rates necessary for postnatal endothermy. If so, the endothermic birds should exhibit a similar remodeling as mammals, which remains to be investigated.

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Section: The Sinus Venosus Is Atrialized In Endothermsmentioning

confidence: 99%

Evolution of the Sinus Venosus from Fish to Human

Jensen

Boukens

Wang

et al. 2014

JCDD

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“…The difference in the electrical and mechanical activity between the SVC and IVC has been described in both humans and animals. 6,7 Spach et al reported that the excitation extended 2-5 cm into the SVC during SR, but no evidence of electrical activity could be found inside the IVC in either humans or animals. 6 These differences may relate to different developmental processes between the 2 venous systems; the SVC is embryologically derived from the anterior cardinal vein, whereas the terminal segment of the IVC is derived from the right vitelline vein.…”

Section: (A) (B)mentioning

confidence: 99%

Focal Source of Atrial Fibrillation Arising From the Ostium of the Inferior Vena Cava

Yamane

Miyazaki

Inada

et al. 2005

Circ J

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lthough it has been established that the initiation and maintenance of paroxysmal atrial fibrillation (AF) is frequently associated with ectopic beats inside the thoracic veins (pulmonary veins: PVs, superior vena cava: SVC, coronary sinus: CS), 1-3 the inferior vena cava (IVC) has been regarded as exempt from arrhythmogenesis. We present a patient with paroxysmal episodes of AF that were initiated and maintained by focal rapid discharges arising from the ostium of the IVC and successfully eliminated by discrete radiofrequency (RF) applications. Case ReportA 57-year-old man with a 3-year history of palpitations was referred for curative treatment of drug-resistant paroxysmal AF. Twelve-lead ECGs recorded before admission demonstrated typical features of both AF and atrial flutter (AFL, suggestive of counterclockwise typical flutter). Other examinations on admission, such as 2-dimensional echocardiogram, chest radiogram, and laboratory tests, were all unremarkable.Mapping of the left atrium and PVs was performed through the patent foramen ovale using a 7-Fr roving ablation catheter and a 7-Fr steerable circular catheter equipped with 10 electrodes. During a period of spontaneous ectopic beats, endocardial recordings in the left atrium, including each of the 4 PVs, did not show any earlier activation relative to the surface P wave.The site of the earliest activation of the ectopic beats was mapped to the antero-medial ostium of the IVC, and this arrhythmogenic focus behaved exactly like those of the PVs (Fig 1). During sinus rhythm (SR), a sharp potential representing the passive IVC activation appeared at the terminal portion of the atrial electrogram and was followed by an ectopic discharge either without conduction to the atrium or provoking a train of spike discharges, which conducted to the remaining atria in an approximately 2-3-to-1 fashion. As demonstrated in Fig 2A, endocardial recordings in both atria showed rapid and organized activity during sustained episodes of AF, preceded by generally regular spike-potentials at the IVC ostium (cycle length: 140-160 ms). Local conduction block (Wenckebach or 2-to-1 block) between the IVC and right atrium (RA) frequently occurred spontaneously or by catheter-tip pressure during sustained tachycardias, producing surface ECG features almost identical to common AFL (Fig 2B).The first application of RF energy at the antero-medial ostium of the IVC (Fig 3) immediately terminated the tachycardia. After additional RF application at the contiguous site, it appeared that IVC pacing only captured the local myocardium without conducting to the atrium, suggesting the electrical isolation of the IVC from the remaining atrium (Fig 4). Because neither ectopic beats nor atrial tachyarrhythmias reappeared, even under isoproterenol infusion and vigorous rapid atrial stimulations, the session was ended with no further RF lesions. The patient has experienced no symptoms or ECG evidence of tachycardia during a 12-month follow-up. DiscussionAlthough it is well recognized that the thoraci...

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“…As to the conduction of the atrial action potentials and contractions to the venae cavae, several papers have already been published (MASHIBA et al, 1963;ITO et al, 1964 andARITA et al, 1966 andARITA, 1966). However, we have as yet very little information on the transmission of impulses from the ventricles to the stem arteries (aorta or pulmonary trunk) as well as their M. ARITA, H. KAWATA AND M. GOTO bulbi, except for a few reports on the amphibia; i. e., a newt or a toad , using a microelectrode (see MAKI and SUZUKI, 1966).…”

Section: Discussionmentioning

confidence: 99%

Measurement of Spontaneous Electrical Activity in the Guinea Pig Pulmonary Bulbus by a Microelectrode

1969

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Studies on Transmembrane Action Potentials and Mechanical Responses of the Venae Cavae and Atria of the Rabbit

Abstract: Since the pulsation of the vena cava was first noticed in the dog by Wallaenus in 1660 (FRANKLIN, 1937), the existence of rhythmical contractions of the venae cavae proximal to the heart in various animals has been reported

Cited by 20 publications

References 20 publications

Evolution of the Sinus Venosus from Fish to Human

Evolution of the Sinus Venosus from Fish to Human

Focal Source of Atrial Fibrillation Arising From the Ostium of the Inferior Vena Cava

Measurement of Spontaneous Electrical Activity in the Guinea Pig Pulmonary Bulbus by a Microelectrode

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