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HYPERTONICITY INCREASES RABBIT ATRIUM AND PULMONARY VEIN ARRHYTHMOGENESIS: A POTENTIAL CONTRIBUTOR TO THE GENESIS OF ATRIAL FIBRILLATION
Author(s) -
Lee ShihHuang,
Chen YaoChang,
Cheng ChenChuan,
Higa Satoshi,
Chen YiJen,
Chen ShihAnn
Publication year - 2009
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.2008.05085.x
Subject(s) - atrial fibrillation , pulmonary vein , medicine , cardiology , atrial action potential , tonicity , electrophysiology , atrium (architecture) , fibrillation , anesthesia , repolarization
SUMMARY1 Pulmonary veins are the most important focus for the initiation of atrial fibrillation. Diabetes mellitus may be associated with hypertonicity and increased occurrence of atrial fibrillation. 2 The purpose of the present study was to investigate whether hypertonicity alters the electrophysiological characteristics of pulmonary veins and atria to enhance the genesis of atrial fibrillation. 3 A whole‐cell patch‐clamp technique was used to investigate action potentials and ionic currents in rabbit isolated single pulmonary vein and atrial cardiomyocytes during immersion in isotonic and hypertonic (1.2× normal osmolality) solutions. 4 Hypertonicity increased the spontaneous beating rates of pulmonary vein cardiomyocytes from 2.3 ± 0.3 to 3.4 ± 0.3 Hz ( n = 11; P < 0.001). Hypertonicity prolonged action potential duration to a greater extent in atrial cardiomyocytes than in pulmonary vein cardiomyocytes. Compared with atrial cardiomyocytes, hypertonicity increased the transient inward currents and Na + /Ca 2+ exchange currents to a greater extent in pulmonary vein cardiomyocytes, but decreased the delayed rectified potassium currents to a lesser extent. 5 Hypertonicity plays an important role in the electrical activity of pulmonary vein and atrial cardiomyocytes, which may have a potential role in the pathophysiology of atrial fibrillation.