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Active vitamin D decreased atrial fibrillation occurrence by 9X and duration by 77X (rabbits) – March 2014

Electromechanical effects of 1,25-dihydroxyvitamin d with antiatrial fibrillation activities.

J Cardiovasc Electrophysiol. 2014 Mar;25(3):317-23. doi: 10.1111/jce.12309. Epub 2013 Nov 14.
Hanafy DA1, Chang SL, Lu YY, Chen YC, Kao YH, Huang JH, Chen SA, Chen YJ.

Treatment with 1,25-dihydroxyvitamin D (1,25[OH]2 D) has several cardiovascular benefits. 1,25[OH]2 D has direct cellular effects, but its effects on the atrium are not clear. We evaluated the effects of 1,25[OH]2 D on the atrial electrophysiology and atrial fibrillation (AF).

Conventional microelectrodes were used to record action potentials (APs) and contractility in isolated rabbit left atrium (LA) tissue preparations before and after the administration of 0.01, 0.1, and 1 nM 1,25[OH]2 D with and without rapid atrial pacing (RAP) and acetylcholine (5 mM)-induced AF. Surface ECG and intracardiac electrograms were recorded before and after the intravenous administration of 4 units/kg of 1,25[OH]2 D in heart failure (HF) rabbits (4 weeks after coronary artery ligation) with RAP and acetylcholine-induced AF.

1,25[OH]2 D dose-dependently increased the AP duration in the LA, which was abolished by pretreatment with 0.1 μM ryanodine. RAP and 5 mM acetylcholine-induced fewer (64.3% vs 100%, P < 0.05) AF occurrences in the presence (n = 14) of 1,25[OH]2 D than those (n = 14) in the absence of 1,25[OH]2 D. The LA treated with 1,25[OH]2 D (n = 9) had a slower maximal AF rate (10.9 ± 2.4 Hz vs 13.3 ± 2.7 Hz, P < 0.05) than the LA (n = 14) without 1,25[OH]2 D. Moreover, 1,25[OH]2 D caused a lower AF inducible percentage (11.0 ± 1.9% vs 100 ± 0%, P < 0.001) and a shorter duration (4 ± 0.4 seconds vs 309 ± 26 seconds, P < 0.001) with a prolonged LA 90% monophasic AP duration (94.1 ± 0.2 milliseconds vs 98.5 ± 0.1 milliseconds, P < 0.05) in 5 rabbits with HF. 1,25[OH]2 D did not prolong the QT interval or 90% of the AP duration in isolated Purkinje fibers.

1,25[OH]2 D has direct electromechanical effects on the LA and can prevent or terminate AF.

Can rent for $6: 2013 Wiley Periodicals, Inc.

PMID: 24152033

See also VitaminDWiki

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