Figure 5.

RA608 attenuates atrial and ventricular arrhythmias in vivo. CaMKIIδc TG mice were treated with either vehicle or a single oral dose of the RA608 (30 mg/kg BW) <4 h prior to programmed electrical burst stimulation in vivo. Original surface ECG recordings (A) show atrial burst stimulation followed by atrial fibrillation upon vehicle treatment but sinus rhythm upon RA608 treatment. Frequency of atrial arrhythmias (B) indicated that RA608 significantly reduced the susceptibility to induced atrial arrhythmias at baseline and upon administration of ISO (mice: vehicle n = 6 and RA608 n = 7). Original surface recordings (C) show ventricular burst stimulation followed by ventricular tachycardia upon vehicle treatment but sinus rhythm upon RA608 treatment. Frequency of ventricular arrhythmias upon administration of ISO (D) was significantly reduced upon treatment with RA608 (but only by trend at baseline, mice: vehicle n = 7 and RA608 n = 7). (B, D) ^* P < 0.05, n − 1 – χ ², as recommended by Campbell.³⁰