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).
Affiliation
Masonic Medical Research Laboratory, Utica, New York, USA.
Journal Details
This article was published in the following journal.
Name: Journal of cardiovascular electrophysiology
ISSN: 1540-8167
Pages:
Links
- 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.
Scimitar Syndrome
An anomalous pulmonary venous return in which the right PULMONARY VEIN is not connected to the LEFT ATRIUM but to the INFERIOR VENA CAVA. Scimitar syndrome is named for the crescent- or Turkish sword-like shadow in the chest radiography and is often associated with hypoplasia of the right lung and right pulmonary artery, and dextroposition of the heart.
Cor Triatriatum
A malformation of the heart in which the embryonic common PULMONARY VEIN was not incorporated into the LEFT ATRIUM leaving behind a perforated fibromuscular membrane bisecting the left atrium, a three-atrium heart. The opening between the two left atrium sections determines the degree of obstruction to pulmonary venous return, pulmonary venous and pulmonary arterial hypertension.
Portal Vein
A short thick vein formed by union of the superior mesenteric vein and the splenic vein.
Catheterization, Swan-ganz
Placement of a balloon-tipped catheter into the pulmonary artery through the antecubital, subclavian, and sometimes the femoral vein. It is used to measure pulmonary artery pressure and pulmonary artery wedge pressure which reflects left atrial pressure and left ventricular end-diastolic pressure. The catheter is threaded into the right atrium, the balloon is inflated and the catheter follows the blood flow through the tricuspid valve into the right ventricle and out into the pulmonary artery.
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