Cardioversion Of Long-lasting Atrial Fibrillation Research Articles

Quinidine for Pharmacological Cardioversion of Long-lasting Atrial Fibrillation.

Background: In the daily clinical practice, patients with atrial fibrillation (AF) lasting more than 48h (or not datable at all) are not uncommon. In long-lasting AF changes in electrophysiological features (electrical remodeling) can occur, resulting in a loss of sensibility to most antiarrhythmic drugs. There is strong evidence that the main mechanism involved in electrical remodeling is a global shortening in refractory period. To assess safety and efficacy of quinidine in pharmacological cardioversion of long-lasting AF, compared with propafenone and amiodarone. Methods and Results: Ninety consecutive patients with AF lasting more than 6 weeks were randomized to amiodarone (5mg\kg bolus, then 15mg\kg in 24h) , propafenone (2 mg\kg bolus then 0.007mg\kg for 2h), and quinidine (275mg of quinidine arabogalattan sulphate per os every 2h for 8h maximum) for pharmacologic cardioversion. All patients had been previously treated with adequate oral anticoagulation and had been submitted to transthoracic echocardiogram. The 3 groups of patients did not differ for baseline and echocardiographic characteristics. Sinus rhythm was restored in 16 patients treated with quinidine (53%), compared with 6 patients (20%) in the amiodarone and propafenone groups (p<0.01). No major adverse effect was reported during the treatment. Conclusions: Quinidine seems to be safe and effective in pharmacological cardioversion of long-lasting AF.

Pharmacological Cardioversion of Long-Lasting Atrial Fibrillation

Pharmacological therapy for atrial fibrillation (AF) is difficult because AF induces atrial remodeling. Randomized prospective studies using amiodarone could not show the superiority of rhythm control strategy to rate control strategy for treatment of AF. Bepridil is a multichannel blocker like amiodarone and expected to be effective for termination of AF without exacerbation of extracardiac adverse effects. Efficacy and safety of bepridil in pharmacological cardioversion of long-lasting AF (≥3 months) was assessed. To avoid the risk of excessive QT prolongation, bepridil dosage was limited to ≤200 mg/day and aprindine (class Ib) was added if necessary. Bepridil alone or in combination with aprindine restored sinus rhythm in 69% of patients. No adverse effects necessitating drug termination occurred. The average time to conversion after starting bepridil was 30 days and cardioversion was associated with significant increase in fibrillation cycle length. After cardioversion, atrial contraction recovered faster within 1 week and sinus rhythm was maintained better than conventional electrical cardioversion. The history of drug-resistant AF did not affect efficacy of bepridil. These observations suggest that pharmacological cardioversion of long-lasting AF could become a new therapeutic option. Although the precise mechanism of cardioversion by bepridil is not clear, reversal of the remodeled atria may play an important role.

Drug-Induced Changes in Fibrillation Cycle Length and Organization Index Can Predict Chemical Cardioversion of Long-Lasting Atrial Fibrillation With Bepridil Alone or in Combination With Aprindine

The aim of this study was to investigate whether drug-induced changes in fibrillation wave characteristics can predict pharmacological conversion of long lasting persistent atrial fibrillation (AF). The study group comprised 23 consecutive patients with AF lasting > or =1 month. Patients first received bepridil (200 mg/day) for 2-4 weeks. When sinus rhythm was not restored with bepridil, oral aprindine (40 or 60 mg/day) was added to bepridil. Fast Fourier transform analysis of fibrillation waves using lead V1 was performed to calculate the fibrillation cycle length (FCL). The spectral areas were measured and the maximum area divided by the total area was termed the fibrillation organization index (FOI). Sinus rhythm was restored in 16 of 23 patients (70%); 8 of these 16 patients received only bepridil (Group I) and the other 8 responders received bepridil and aprindine (Group II). In Group I bepridil increased both FCL (p<0.001) and FOI (p<0.01) and terminated AF after 20+/-12 days. In Group II bepridil increased FCL (p<0.001), but did not change FOI. The addition of aprindine terminated AF in association with an increase in both FCL (p<0.005) and FOI (p<0.005) within 19+/-8 days. In the remaining 7 patients who did not have restoration of sinus rhythm, bepridil increased both FCL and FOI significantly, but less than in Group I, and the addition of aprindine did not further increase either of them. Chemical cardioversion of AF occurred in all patients with FCL > or =190 ms and FOI > or =45% after drug administration. Bepridil alone or in combination with aprindine converted long lasting persistent AF in association with an increase in both FCL and FOI. The combination of FCL and FOI after drug administration is helpful in predicting chemical cardioversion of persistent AF.

Effects of verapamil and metoprolol on recovery from atrial electrical remodeling after cardioversion of long-lasting atrial fibrillation

The aim of this prospective, randomized study was to investigate the effect of pretreatment with two different intracellular calcium-lowering drugs (verapamil and metoprolol) on recovery from atrial effective refractory period (AERP) shortening after internal electrical cardioversion (EC) of persistent atrial fibrillation (AF) in patients on amiodarone. Twenty-one patients on amiodarone for at least 30 days were referred to our hospital for internal EC of a persistent AF refractory to external EC. They were randomized to receive only amiodarone (group AMI, n=7), or amiodarone and verapamil 240 mg/day (group VER, n=7), or amiodarone and metoprolol 100 mg/day (group MET, n=7). Left AERP was measured 10 min and 24 h after EC. AERP was also determined in 13 controls. The AERP after 10 min was significantly shorter in group AMI (201 (31) ms, P<0.02) and group MET (203 (34) ms, P<0.03) than in controls (249 (45) ms), but not in group VER (237 (51) ms, P=NS). The AERP after 24 h was still significantly shorter in group AMI (204 (38) ms, P<0.04) than in controls, but not in group MET (225 (52) ms, P=NS) or in group VER (290 (36) ms, P=NS). Pretreatment with amiodarone and verapamil prevents AERP shortening, while pretreatment with amiodarone and metoprolol only accelerated AERP recovery.

Early relapses of atrial fibrillation after internal cardioversion of long-lasting atrial fibrillation: Relation with autonomic nervous system

Early relapses of atrial fibrillation after internal cardioversion of long-lasting atrial fibrillation: Relation with autonomic nervous system

Early relapses of atrial fibrillation after internal cardioversion of long-lasting atrial fibrillation: Relation with autonomic nervous system

Early relapses of atrial fibrillation after internal cardioversion of long-lasting atrial fibrillation: Relation with autonomic nervous system