Search

Among the drugs recommended to prevent recurrences of atrial fibrillation after external electric shock, antiarrhythmic agents of classes Ia (quinidine, disopyramide), Ic (cibenzoline, flecainide, propafenone) and III (sotalol) seem to have the same effectiveness in maintaining the sinus rhythm in about 50 percent of the cases after 6 months and one year. Amiodarone, seldom used as first-line treatment, appears to be the most effective drug. The percentage of side-effects requiring discontinuation of treatment is the same for all drugs (about 10 percent). All these drugs have potential proarrhythmic effects. In case of recurrence electric shocks can be repeated in some special cases. The therapeutic strategy according to the clinical context (atrial fibrillation of vagal nerve or catecholergic origin, normal or altered left ventricular function) is discussed.

Internal cardioversion is a new method of treating atrial fibrillation. It consists in delivering an electric shock between an electrode positioned in the right atrium and a dorsal electrode. A quadripolar electrophysiological catheter is used as the proximal electrode, the two distal poles of which are used to locate the His bundle deflection. Care is taken that the electrode used for cardioversion is not in contact with the atrial wall by using biplane fluoroscopy and unipolar endocavitary recordings. Twenty-eight patients (18 men and 10 women) average age 55 years, underwent this treatment for chronic atrial fibrillation resistant to one or two attempts at external cardioversion. Each patient was given one or two shocks (average 1.68) in the same session. There were 22 immediate reversions to sinus rhythm, giving a primary success rate of 78.57%. Four patients relapsed in the 3 days following the procedure, giving a short term success rate of 64.28%. The minimum effective energy would seem to be 200 joules. The only rhythm complications were sinus bradycardia and/or atrioventricular block lasting a few seconds, both countered by prophylactic ventricular pacing : no traumatic complications due to electric shock were observed. The long term results show sinus rhythm maintained in 66.66% of patients at 6 months and more. In conclusion, internal cardioversion is an effective method of treating cardiac arrhythmias resistant to external cardioversion. The procedure would seem to be reliable and relatively atraumatic. The long term results are promising, particularly the stability of sinus rhythm which seems to be longer than after external cardioversion, by they need further confirmation.