First, selective inhibition of AT1R by ARB may lead to compensatory increases in angiotensin II concentration, allowing free angiotensin II to bind to AT2R.8,23 Stimulation of AT2R has been reported to enhance nitric oxide secretion, which is associated with decreased AF in patients with cerebral infarction.24–26 Second, experimental studies showed that some ARBs, that is, candesartan and irbesartan, 2 commonly used ARBs in Taiwan, possess direct antiarrhythmic properties.13,27 Candesartan and irbesartan use in the ARB group might have contributed to the reduced AF risk in this study. The gene discussed is AGTR1; the disease is atrial fibrillation.