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.
Nomura
Masahiro
M
Faculty of Integrated Arts and Science, Department of Digestive and Cardiovascular Medicine, The University of Tokushima Graduate School, The University of Tokushima, Japan. nomura@ias.tokushima-u.ac.jp
Kawano
Tomohito
T
Nakayasu
Kimiko
K
Nakaya
Yutaka
Y
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology*; D018780:Body Surface Potential Mapping / Q000187:drug effects / Q000379:methods; D004562:Electrocardiography / Q000187:drug effects* / Q000379:methods; D005260:Female; D006801:Humans; D019808:Losartan / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged
D000889:Anti-Arrhythmia Agents; D019808:Losartan