Extended Data Fig. 10: Recording of fatal arrhythmias in two infarcted pigs treated with AAV6-miR-199a-3p.

Initiation of ventricular fibrillation recorded at the moment of death in two AAV6-miR-199a pigs by implanted miniaturized ECG recorders (Reveal, Medtronic, 9529). a, A premature ventricular ectopic beat (red arrow) with a coupling interval of 380 ms during a slowing heart rhythm induced a fast ventricular tachycardia that degenerated in ventricular fibrillation. b, A premature ventricular ectopic beat (red arrow) with coupling interval of 350 ms induced a fast ventricular tachycardia that quickly degenerated in ventricular fibrillation of different amplitudes resembling polymorphic ventricular tachycardia. c. AAV6-mediated, long-term expression of miR-199a did not affect the expression levels of ion channels or associated proteins involved in known arrhythmogenic conditions. In the infarct border zone of pigs treated with AAV6-control or AAV6-miR-199a (n = 6 and n = 4, respectively) at 30 days after transduction, the expression levels of genes known to be involved in the pathogenesis of long QT syndrome (SCN5A, KCNE1, SNTA1, AKAP9 and ANK2), Brugada syndrome (CACNA1, CACNB2 and SCN1B), Carvajal syndrome (DSP), arrhythmogenic right ventricular cardiomyopathy (DSG2 and DSP) and catecholaminergic polymorphic ventricular tachycardia (CASQ2 and RYR2) were assessed. Additional investigated mRNAs were those coding for SERCA2A (which is encoded by ATP2A2 and also served as a positive control since it is depressed during heart failure and was found increased in miR-199a-treated animals), phospholamban (PLN) and connexins 40 and 43 (CX40 (which is encoded by GJA1) and CX43 (which is encoded by GJA5), respectively). The miR-199a-treated pigs in which analysis was performed included one pig that survived eight weeks (pig 50) and three pigs that died from sudden death at seven weeks (pigs 55, 66 and 67). Data are mean ± s.e.m. *P < 0.05 versus AAV6-control; Student’s two-sided t-test.