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Intracellular calcium dynamics and anisotropic reentry in isolated canine pulmonary veins and left atrium.
Circulation. 2005 Jun 07; 111(22):2889-97.Circ

Abstract

BACKGROUND

Rapid activations due to either focal discharge or reentry are often present during atrial fibrillation (AF) in the pulmonary veins (PVs). The mechanisms of these rapid activations are unclear.

METHODS AND RESULTS

We studied 7 isolated, Langendorff-perfused canine left atrial (LA) and PV preparations and used 2 cameras to map membrane potential alone (Vm, n=3) or Vm and intracellular calcium simultaneously (Ca(i), n=4). Rapid atrial pacing induced 26 episodes of focal discharge from the proximal PVs in 5 dogs. The cycle lengths were 223+/-52 ms during ryanodine infusion (n=13) and 133+/-59 ms during ryanodine plus isoproterenol infusion (n=13). The rise of Ca(i) preceded Vm activation at the sites of focal discharge in 6 episodes of 2 preparations, compatible with voltage-independent spontaneous Ca(i) release. Phase singularities during pacing-induced reentry clustered specifically at the PV-LA junction. Periodic acid-Schiff (PAS) stain identified large cells with pale cytoplasm along the endocardium of PV muscle sleeves. There were abrupt changes in myocardial fiber orientation and increased interstitial fibrosis in the PV and at the PV-LA junction.

CONCLUSIONS

PV muscle sleeves may develop voltage-independent Ca(i) release, resulting in focal discharge. Focal discharge may also be facilitated by the presence of PAS-positive cells that are compatible with node-like cells. During reentry, phase singularities clustered preferentially at sites of increased anisotropy such as the PV-LA junction. These findings suggest that focal discharge caused by spontaneous calcium release and anisotropic reentry both contribute to rapid activations in the PVs during AF.

Authors+Show Affiliations

Chou CC
Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, Calif 90048, USA.
Nihei M
No affiliation info available
Zhou S
No affiliation info available
Tan A
No affiliation info available
Kawase A
No affiliation info available
Macias ES
No affiliation info available
Fishbein MC
No affiliation info available
Lin SF
No affiliation info available
Chen PS
No affiliation info available

MeSH

Action PotentialsAnimalsAnisotropyAtrial FibrillationCalciumDisease Models, AnimalDogsHeartHeart AtriaHistological TechniquesIn Vitro TechniquesMyocardiumPerfusionPulmonary Veins

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15927973

Citation

Chou, Chung-Chuan, et al. "Intracellular Calcium Dynamics and Anisotropic Reentry in Isolated Canine Pulmonary Veins and Left Atrium." Circulation, vol. 111, no. 22, 2005, pp. 2889-97.
Chou CC, Nihei M, Zhou S, et al. Intracellular calcium dynamics and anisotropic reentry in isolated canine pulmonary veins and left atrium. Circulation. 2005;111(22):2889-97.
Chou, C. C., Nihei, M., Zhou, S., Tan, A., Kawase, A., Macias, E. S., Fishbein, M. C., Lin, S. F., & Chen, P. S. (2005). Intracellular calcium dynamics and anisotropic reentry in isolated canine pulmonary veins and left atrium. Circulation, 111(22), 2889-97.
Chou CC, et al. Intracellular Calcium Dynamics and Anisotropic Reentry in Isolated Canine Pulmonary Veins and Left Atrium. Circulation. 2005 Jun 7;111(22):2889-97. PubMed PMID: 15927973.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intracellular calcium dynamics and anisotropic reentry in isolated canine pulmonary veins and left atrium. AU - Chou,Chung-Chuan, AU - Nihei,Motoki, AU - Zhou,Shengmei, AU - Tan,Alex, AU - Kawase,Ayaka, AU - Macias,Edgar S, AU - Fishbein,Michael C, AU - Lin,Shien-Fong, AU - Chen,Peng-Sheng, Y1 - 2005/05/31/ PY - 2005/6/2/pubmed PY - 2006/1/26/medline PY - 2005/6/2/entrez SP - 2889 EP - 97 JF - Circulation JO - Circulation VL - 111 IS - 22 N2 - BACKGROUND: Rapid activations due to either focal discharge or reentry are often present during atrial fibrillation (AF) in the pulmonary veins (PVs). The mechanisms of these rapid activations are unclear. METHODS AND RESULTS: We studied 7 isolated, Langendorff-perfused canine left atrial (LA) and PV preparations and used 2 cameras to map membrane potential alone (Vm, n=3) or Vm and intracellular calcium simultaneously (Ca(i), n=4). Rapid atrial pacing induced 26 episodes of focal discharge from the proximal PVs in 5 dogs. The cycle lengths were 223+/-52 ms during ryanodine infusion (n=13) and 133+/-59 ms during ryanodine plus isoproterenol infusion (n=13). The rise of Ca(i) preceded Vm activation at the sites of focal discharge in 6 episodes of 2 preparations, compatible with voltage-independent spontaneous Ca(i) release. Phase singularities during pacing-induced reentry clustered specifically at the PV-LA junction. Periodic acid-Schiff (PAS) stain identified large cells with pale cytoplasm along the endocardium of PV muscle sleeves. There were abrupt changes in myocardial fiber orientation and increased interstitial fibrosis in the PV and at the PV-LA junction. CONCLUSIONS: PV muscle sleeves may develop voltage-independent Ca(i) release, resulting in focal discharge. Focal discharge may also be facilitated by the presence of PAS-positive cells that are compatible with node-like cells. During reentry, phase singularities clustered preferentially at sites of increased anisotropy such as the PV-LA junction. These findings suggest that focal discharge caused by spontaneous calcium release and anisotropic reentry both contribute to rapid activations in the PVs during AF. SN - 1524-4539 UR - https://www.unboundmedicine.com/medline/citation/15927973/Intracellular_calcium_dynamics_and_anisotropic_reentry_in_isolated_canine_pulmonary_veins_and_left_atrium_ DB - PRIME DP - Unbound Medicine ER -