The effects of losartan on signal-averaged P wave in patients with atrial fibrillation

Background: Losartan has recently been reported to suppress atrial structural remodeling. However, few reports exist on signal-averaged electrocardiography (ECG) for preventing atrial electrical remodeling. We examined the effect of losartan on atrial electricity by using signal-averaged ECG of P waves. Methods: The subjects comprised 40 patients with essential hypertension complicated with symptomatic paroxysmal atrial fibrillation. The patients received pilsicainide for the complication; they were defibrillated and divided into two subgroups for antihypertensive therapy: calcium antagonist-administrated (CB) and losartan-administrated (LOS) groups. We recorded the signal-averaged electrocardiography of P waves and calculated (1) filtered P wave duration (PD), (2) the voltage integral for the entire P wave (integral-p), and (3) the root mean square voltages of the terminal 40, 30, and 20 ms (RMS-40, RMS-30, and RMS-20). Procollagen C propeptide type I (PIP) and A- and B-type natriuretic peptide (ANP and BNP, respectively) levels in the groups were measured before and after antihypertensive agent administration. Results: RMS-20 increased significantly and PD decreased significantly in the LOS group 24 weeks after antihypertensive drug administration; however, they remained unchanged in the CB group. Integral-p decreased significantly in both groups, and the decrease rate was significantly higher in the LOS group. Serum BNP levels decreased significantly only in the LOS group. Conclusions: Losartan inhibits atrial remodeling by inhibiting left atrial fibrosis as indicated by the procollagen C propeptide type I, ANP, and BNP levels. Signal-averaged ECG demonstrated that losartan suppresses atrial fibrillation recurrence by improving atrial conduction disturbance. (c) 2007 Elsevier Ireland Ltd. All rights reserved.