Effects of acute atrial dilation on heterogeneity in conduction in the isolated rabbit heart

Autor:	Mohamed Majidi, Marc A. M. J. van Zandvoort, Sabine Eijsbouts, Maurits A. Allessie
Rok vydání:	2003
Předmět:	medicine.medical_specialty Atrial Pressure Nerve conduction velocity Heart Conduction System Physiology (medical) Internal medicine Atrial Fibrillation medicine Pressure Animals cardiovascular diseases Heart Atria business.industry Cardiac Pacing Artificial Atrial fibrillation Anatomy Thermal conduction medicine.disease Electrophysiology medicine.anatomical_structure cardiovascular system Cardiology Dilation (morphology) Rabbits Cardiology and Cardiovascular Medicine Sinoventricular conduction Crista terminalis business
Zdroj:	Journal of cardiovascular electrophysiology. 14(3)
ISSN:	1045-3873
Popis:	Introduction: Atrial dilation plays an important role in the development and persistence of atrial fibrillation (AF). The mechanisms by which atrial dilation increases the vulnerability to AF are not fully understood. Methods and Results: In 11 isolated rabbit hearts, the right atrium was acutely dilated by increasing the intra-atrial pressure from 2 to 9 and 14 cm H2O. A rectangular mapping array of 240 electrodes (spatial resolution 0.5 mm) was positioned on the free wall of the right atrium. The atrium was paced from four different sites at intervals of 240 and 125 msec. At normal atrial pressure (2 cm H2O), conduction was uniform in all directions with an anisotropy ratio between 1.5 and 1.7. Increasing the pressure to 9 cm H2O decreased the normalized conduction velocity during rapid pacing by 18%. The incidence of areas of slow conduction and conduction block increased from 6.6% and 1.6% to 10.2% and 3.3%. At 14 cm H2O, conduction velocity decreased by 31% and the percentage of slow conduction and block further increased to 11.5% and 6.6%(P < 0.001).The appearance of lines of intra-atrial block was largely dependent on the pacing site. Whereas during pacing at the cranial part of the crista terminalis no increase in conduction delays occurred, pacing from the low right atrium unmasked several lines of block oriented parallel to the major trabeculae and the crista terminalis. In an additional series of six hearts the left atrium also was mapped. The effect of dilation of the left atrium was comparable to that of the right atrium. Increasing the atrial pressure to 14 cm H2O increased the amount of intra-atrial conduction block threefold to fourfold. Conclusion: Acute atrial dilation results in slowing of conduction and an increase of the amount of intra-atrial conduction block. The increase in spatial heterogeneity in conduction was related to the anisotropic properties of the atrial wall.(J Cardiovasc Electrophysiol, Vol. 14, pp. 269-278, March 2003)
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cb4223790d6c1992c79d41d1cde0e6ca https://pubmed.ncbi.nlm.nih.gov/12716110 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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