Telemetry electrocardiogram (ECG) recordings revealed that conscious PKP2 Het mice displayed baseline electrophysiological abnormalities (marked by the presence of premature ventricular contractions (PVCs)) in the absence of cardiomyopathy, as assessed by in vivo magnetic resonance imaging (MRI), which may account for premature lethality and sudden cardiac death at later ages (Extended Data Fig. 1). This evidence concerns the gene PKP2 and cardiomyopathy.