Independent risk factors included substrate size [hazard ratio (HR), 1.13; 95% confidence interval (CI), 1.08–1.18; P < 0.001], aborted cardiac arrest (HR, 2.98; 95% CI, 1.68–5.28; P < 0.001), and SCN5A variants (HR, 2.22; 95% CI, 1.15–4.27; P = 0.017). The gene discussed is SCN5A; the disease is cardiac arrest.