Fig. 2.

Atrial fibrillation (AF) in FK506-binding protein 12 transgenic (αMyHC-FKBP12) mice. A: paroxysmal AF documented by ambulatory ECG. B: the diagnosis of AF was supported by the absence of P waves despite the presence of clear P waves during sinus rhythm and irregular rhythm, which was evident in the 5-min cycle length histogram. C: AF occurred spontaneously during the electrophysiological experiment (top traces). Note that the termination of AF was followed by prolonged sinus pause (bottom traces), suggesting abnormal sinus node function. AE, atrial ectopy; pECG, pseudo ECG; iECG, intracardiac electrograms.