Erschienen in:
01.05.2012 | Original Contribution
Genetic suppression of Gαs protein provides rate control in atrial fibrillation
verfasst von:
Patrick Lugenbiel, Dierk Thomas, Kamilla Kelemen, Kerstin Trappe, Olympia Bikou, Patrick A. Schweizer, Frederik Voss, Rüdiger Becker, Hugo A. Katus, Alexander Bauer
Erschienen in:
Basic Research in Cardiology
|
Ausgabe 3/2012
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Abstract
Gene therapy-based modulation of atrioventricular (AV) conduction by overexpression of a constitutively active inhibitory Gα
i
protein effectively reduced heart rates in atrial fibrillation (AF). However, catecholamine stimulation caused an excessive increase in ventricular rate. We hypothesized that modest genetic suppression of a stimulatory G protein in the AV node would allow persistent rate control in acute AF and would prevent undesired heart rate acceleration during β-adrenergic activation. Atrial fibrillation was induced in 12 pigs by atrial burst pacing via an implanted cardiac pacemaker. Study animals were then assigned to receive either Ad-siRNA-Gαs gene therapy to inactivate Gαs protein or Ad-β-gal as control. Gαs protein inactivation resulted in a 20 % heart rate reduction (P < 0.01). AH and HV intervals were prolonged by 37 ms (P < 0.001) and 28 ms (P < 0.001), respectively, demonstrating atrioventricular conduction delay. Impairment of left ventricular ejection fraction (LVEF) during AF was attenuated by Gαs suppression (LVEF 49 %) compared with controls (LVEF 34 %; P = 0.03). Isoproterenol application accelerated ventricular heart rate from 233 to 281 bpm (P < 0.001) in control animals but did not significantly affect pigs treated with Ad-siRNA-Gαs (192 vs. 216 bpm; P = 0.19). In conclusion, genetic inhibition of Gαs protein in the AV node reduced heart rate and prevented AF-associated reduction of cardiac function in a porcine model. Rate control by gene therapy may provide an alternative to current pharmacological treatment of AF.