Kazuko Tajiri1,2, Jean-Baptiste Guichard1,3, Xiaoyan Qi1, Feng Xiong1, Patrice Naud1, Jean-Claude Tardif1, Antoine Da Costa3, Kazutaka Aonuma2, Stanley Nattel1,4,5,6. 1. Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Belanger St E, Montreal, Quebec, Canada. 2. Department of Cardiology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan. 3. Department of Cardiology, University Hospital of Saint-Étienne, University Jean Monnet, Saint-Étienne, France. 4. Department of Pharmacology and Therapeutics, McGill University, Promenade Sir-William-Osler, Montreal, Quebec, Canada. 5. Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Hufelandstr. 55, Essen, Germany. 6. IHU LIRYC and Fondation Bordeaux Université, Avenue du Haut Lévêque, Pessac, Bordeaux, France.
Abstract
AIMS: Autonomic dysfunction can promote atrial fibrillation (AF) and results from AF-related remodelling. N-type Ca2+-channels (NTCCs) at sympathetic nerve terminals mediate Ca2+-entry that triggers neurotransmitter release. AF-associated remodelling plays an important role in AF pathophysiology but the effects of NTCC inhibition on such remodelling is unknown. Here, we investigated the ability of a clinically available Ca2+-channel blocker (CCB) with NTCC-blocking activity to suppress the arrhythmogenic effects of AF-promoting remodelling in dogs. METHODS AND RESULTS: Mongrel dogs were kept in AF by right atrial tachypacing at 600 bpm. Four groups were studied under short-term AF (7 days): (i) Shams, instrumented but without tachypacing (n = 5); (ii) a placebo group, tachypaced while receiving placebo (n = 6); (iii) a control tachypacing group receiving nifedipine (10 mg orally twice-daily; n = 5), an L-type CCB; and (iv) a cilnidipine group, subjected to tachypacing and treatment with cilnidipine (10 mg orally twice-daily; n = 7), an N-/L-type CCB. With cilnidipine therapy, dogs with 1-week AF showed significantly reduced autonomic changes reflected by heart rate variability (decreases in RMSSD and pNN50) and plasma norepinephrine concentrations. In addition, cilnidipine-treated dogs had decreased extracellular matrix gene expression vs. nifedipine-dogs. As in previous work, atrial fibrosis had not yet developed after 1-week AF, so three additional groups were studied under longer-term AF (21 days): (i) Shams, instrumented without tachypacing or drug therapy (n = 8); (ii) a placebo group, tachypaced while receiving placebo (n = 8); (iii) a cilnidipine group, subjected to tachypacing during treatment with cilnidipine (10 mg twice-daily; n = 8). Cilnidipine attenuated 3-week AF effects on AF duration and atrial conduction, and suppressed AF-induced increases in fibrous-tissue content, decreases in connexin-43 expression and reductions in sodium-channel expression. CONCLUSIONS: Cilnidipine, a commercially available NTCC-blocking drug, prevents AF-induced autonomic, electrical and structural remodelling, along with associated AF promotion. Published on behalf of the European Society of Cardiology. All rights reserved.
AIMS: Autonomic dysfunction can promote atrial fibrillation (AF) and results from AF-related remodelling. N-type Ca2+-channels (NTCCs) at sympathetic nerve terminals mediate Ca2+-entry that triggers neurotransmitter release. AF-associated remodelling plays an important role in AF pathophysiology but the effects of NTCC inhibition on such remodelling is unknown. Here, we investigated the ability of a clinically available Ca2+-channel blocker (CCB) with NTCC-blocking activity to suppress the arrhythmogenic effects of AF-promoting remodelling in dogs. METHODS AND RESULTS: Mongrel dogs were kept in AF by right atrial tachypacing at 600 bpm. Four groups were studied under short-term AF (7 days): (i) Shams, instrumented but without tachypacing (n = 5); (ii) a placebo group, tachypaced while receiving placebo (n = 6); (iii) a control tachypacing group receiving nifedipine (10 mg orally twice-daily; n = 5), an L-type CCB; and (iv) a cilnidipine group, subjected to tachypacing and treatment with cilnidipine (10 mg orally twice-daily; n = 7), an N-/L-type CCB. With cilnidipine therapy, dogs with 1-week AF showed significantly reduced autonomic changes reflected by heart rate variability (decreases in RMSSD and pNN50) and plasma norepinephrine concentrations. In addition, cilnidipine-treated dogs had decreased extracellular matrix gene expression vs. nifedipine-dogs. As in previous work, atrial fibrosis had not yet developed after 1-week AF, so three additional groups were studied under longer-term AF (21 days): (i) Shams, instrumented without tachypacing or drug therapy (n = 8); (ii) a placebo group, tachypaced while receiving placebo (n = 8); (iii) a cilnidipine group, subjected to tachypacing during treatment with cilnidipine (10 mg twice-daily; n = 8). Cilnidipine attenuated 3-week AF effects on AF duration and atrial conduction, and suppressed AF-induced increases in fibrous-tissue content, decreases in connexin-43 expression and reductions in sodium-channel expression. CONCLUSIONS:Cilnidipine, a commercially available NTCC-blocking drug, prevents AF-induced autonomic, electrical and structural remodelling, along with associated AF promotion. Published on behalf of the European Society of Cardiology. All rights reserved.
Authors: Kenya Kusunose; Youhua Zhang; Todor N Mazgalev; David R Van Wagoner; James D Thomas; Zoran B Popović Journal: Circ Heart Fail Date: 2014-01-07 Impact factor: 8.790
Authors: Oleg F Sharifov; Vadim V Fedorov; Galina G Beloshapko; Alexey V Glukhov; Anna V Yushmanova; Leonid V Rosenshtraukh Journal: J Am Coll Cardiol Date: 2004-02-04 Impact factor: 24.094