Despite the close link between hypertension and atrial fibrillation, the underlying pathophysiology of atrial fibrillation in patients with hypertension remains unclear. Furthermore, although all classes of antihypertensive medication may potentially reduce the risk of atrial fibrillation, some studies suggest that drugs targeting the renin-angiotensin system may be particularly favourable because of their effect on atrial remodelling.
To further investigate, researchers identified Danish patients treated with only one class of antihypertensive medication (from the entire Danish population; n= 6.7million), and matched individuals treated with ACEis 1:1 with individuals treated with β-blockers, (n = 48 658), diuretic (n = 69 630), calcium-antagonist (n = 57 646), and ARB monotherapy (n = 20 158). Likewise, individuals treated with ARBs were matched 1:1 with individuals treated with β-blockers (n = 20 566), diuretic (n = 20 832), calcium-antagonist (n = 20 232), and ACEi monotherapy (n = 20 158). All individuals were free of atrial fibrillation and of predisposing diseases like heart failure, ischaemic heart disease, diabetes mellitus, and hyperthyroidism at baseline and none received any other antihypertensive medication.
The researchers reported the following results:
• Hazard ratios of atrial fibrillation for ACEi and ARB monotherapy were 0.12 (95% CI: 0.10–0.15) and 0.10 (0.07–0.14) compared with β-blocker, 0.51 (0.44–0.59) and 0.43 (0.32–0.58) compared with diuretic, and 0.97 (0.81–1.16) and 0.78 (0.56–1.08) compared with calcium-antagonist monotherapy.
• Risk of stroke (influenced by lowering blood pressure rather than renin-angiotensin system blockade) did not differ among the five antihypertensives.
The authors note that the data are limited by their retrospective nature. Confounding factors include the receipt of antihypertensives for indications other than hypertension. There was also no information provided on blood pressure control or patient characteristics, clinical course or other clinical parameters. Finally β-blockers may have been selected as a preferred option for hypertensive individuals with palpitations.
Overall, the authors note that the use of ACEis and ARBs compared with β-blockers and diuretics is associated with a reduced risk of atrial fibrillation, but not stroke. These findings thus suggest that controlling activation of the renin-angiotensin system in addition to controlling blood pressure and thereby haemodynamic changes may help reduce the risk of atrial fibrillation.