Site of Origin and Molecular Substrate of Atrioventricular Junctional Rhythm in the Rabbit Heart

ABSTRACT—During failure of the sinoatrial node, the heart can be driven by an atrioventricular (AV) junctional pacemaker. The position of the leading pacemaker site during AV junctional rhythm is debated. In this study, we present evidence from high-resolution fluorescent imaging of electrical activ...

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Veröffentlicht in:Circulation research 2003-11, Vol.93 (11), p.1102-1110
Hauptverfasser: Dobrzynski, Halina, Nikolski, Vladimir P, Sambelashvili, Alexandre T, Greener, Ian D, Yamamoto, Mitsuru, Boyett, Mark R, Efimov, Igor R
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Sprache:eng
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Zusammenfassung:ABSTRACT—During failure of the sinoatrial node, the heart can be driven by an atrioventricular (AV) junctional pacemaker. The position of the leading pacemaker site during AV junctional rhythm is debated. In this study, we present evidence from high-resolution fluorescent imaging of electrical activity in rabbit isolated atrioventricular node (AVN) preparations that, in the majority of cases (11 out of 14), the AV junctional rhythm originates in the region extending from the AVN toward the coronary sinus along the tricuspid valve (posterior nodal extension, PNE). Histological and immunohistochemical investigation showed that the PNE has the same morphology and unique pattern of expression of neurofilament160 (NF160) and connexins (Cx40, Cx43, and Cx45) as the AVN itself. Block of the pacemaker current, If, by 2 mmol/L Cs increased the AV junctional rhythm cycle length from 611±84 to 949±120 ms (mean±SD, n=6, P
ISSN:0009-7330
1524-4571
DOI:10.1161/01.RES.0000101913.95604.B9