['Differential drug treatment guided by the underlying heart disease may improve outcome of rhythm control therapy. In the present study we investigated in a well-defined group with either lone atrial fibrillation (AF) or hypertension whether there were differences in rhythm control outcome between both groups in relation to the use of cardiovascular drugs.', "One hundred sixty-two patients were included after successful cardioversion of persistent AF. None of the patients was given a class I or III antiarrhythmic drug. Patients' heart rhythm was checked 3 times a day, using transtelephonic monitoring for 1 month after cardioversion. One month after cardioversion up to 68% of patients had a recurrence of persistent AF. During the first 3 days almost no recurrences were seen on beta-blocker therapy whereas recurrences peaked on day 2-3 in the absence of beta-blockers. Univariate analysis showed that the use of beta-adrenergic receptor blockers and the presence of hypertension were associated with a lower recurrence rate at 1 month. Multivariate logistic regression analysis demonstrated that beta-blockade was the only statistically significant parameter predicting sinus rhythm at 1 month (OR 0.40, 95% CI 0.19-0.86, P=0.02)."] Do beta-blockers prevent subacute recurrences of persistent atrial fibrillation only in patients with hypertension?