Antiarrhythmic Effects of Losartan and Enalapril in Canine Pulmonary Vein Sleeve Preparations.
Summary of "Antiarrhythmic Effects of Losartan and Enalapril in Canine Pulmonary Vein Sleeve Preparations."
Antiarrhythmic Effect of Losartan and Enalapril. Introduction: Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II-receptor blockers (ARBs) are prototypes of "upstream" therapy for the management of atrial fibrillation (AF). Ectopic activity arising from the PV sleeves plays a prominent role in the development of AF. Methods: Transmembrane action potentials were recorded from canine superfused left superior or inferior PV sleeves using standard microelectrode techniques. Acetylcholine (ACh, 1 μM), isoproterenol (1 μM), high calcium ([Ca(2+) ](o) = 5.4 mM) or a combination was used to induce early or delayed afterdepolarizations (EADs or DADs) and triggered activity. Results: The ARB losartan (1 μM, n = 5) and the ACE inhibitor enalapril (10 μM, n = 5) produced no significant change in action potential duration, maximum rate of rise of action potential upstroke (V(max) ), action potential amplitude or take-off potential at basic cycle lengths of 200 to 2000 ms. Losartan (1 μM) and enalapril (10-20 μM) markedly attenuated or suppressed EADs and DAD-induced triggered activity elicited by exposure of the PV sleeves to ACh, isoproterenol or high calcium following rapid pacing in 6 of 6 (losartan) and 4 of 5 (enalapril) PV sleeve preparations. Neither losartan nor enalapril altered Ca(2+) or K(+) channel currents in enzymatically-dissociated atrial myocytes at these concentrations. Conclusions: Our data suggest that in addition to their "upstream" effects to reduce atrial structural remodeling, ACE inhibitors and ARBs exert a "direct" antiarrhythmic effect by suppressing triggers responsible for the genesis of AF and other atrial arrhythmias. (J Cardiovasc Electrophysiol, Vol. pp. 1-8).
Masonic Medical Research Laboratory, Utica, New York, USA.
This article was published in the following journal.
Name: Journal of cardiovascular electrophysiology
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21159010
- DOI: http://dx.doi.org/10.1111/j.1540-8167.2010.01972.x
Medical and Biotech [MESH] Definitions
Hepatitis, Infectious Canine
A contagious disease caused by canine adenovirus (ADENOVIRUSES, CANINE) infecting the LIVER, the EYE, the KIDNEY, and other organs in dogs, other canids, and bears. Symptoms include FEVER; EDEMA; VOMITING; and DIARRHEA.
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