GJA1 and ventricular fibrillation: In a canine infarct model, delivery of 15 Gy via 12C radiation resulted in the reversal of conduction slowing and reduction in VT/ventricular fibrillation inducibility, with the upregulation of connexin 43.27 Left ventricular systolic function was also improved with radiation delivery compared to the untreated animals with myocardial infarction, which was thought to be due to increased connexin 43 expression within the infarcted regions.