(A) Representative examples for a premature ventricular contraction (PVC) and ventricular tachycardia (VT). Summary data are presented in (B), n=16 each. (C) QRS duration was prolonged within a few minutes after Iso injection in TnT-I79N, but not TnT-WT mice. (D) Typical Western blot pattern for anti-Cx43 (isoforms P2, P1, P0 indicated) after Iso treatment, (E) Total expression of Cx43 and (F) P0/P2 isoform ratio analyzed by Western blot. N numbers are indicated in columns and are the same for (E) and (F). * p≤0.05 vs WT