Internal low energy atrial cardioversion: Efficacy and safety in older patients with chronic persistent atrial fibrillation

BACKGROUND: Low-energy internal atrial cardioversion is a relatively new te chnique based on delivery of intracardiac shocks through transvenous cathet ers placed into the atria or the vessels. OBJECTIVE: The aim of this study was to assess in older and younger patient s with chronic persistent atrial fibrillation (AF) the efficacy and safety of transvenous low-energy internal atrial cardioversion performed without r outine administration of sedatives or anesthetics. DESIGN: A prospective longitudinal study. SETTING: A cardiological university hospital. PARTICIPANTS: 82 patients, divided into older (greater than or equal to 60 years) (n = 49) and younger (n = 33) subjects. MEASUREMENTS: Atrial defibrillation threshold for internal cardioversion, m easured as leading edge voltage (V) and delivered energy (J) of effective s hocks, percentage of patients maintaining sinus rhythm at short-term (withi n 3 days) and at long-term follow-up. METHODS: Patients with chronic persistent AF, treated with oral anticoagula nts for at least 3 to 4 weeks, were admitted to hospital. Following a clini cal work-up, patients were subjected to low-energy internal atrial cardiove rsion with shock delivery according to a step-up protocol. RESULTS: Internal cardioversion was effective in restoring sinus rhythm in 90% (44/49) of the older patients and in 94% (31/33) of the younger patient s. Shocks were effective at a mean energy between 6 and 8 joules (range 0.9 -23) and administration of sedatives or anesthetics was required during the procedure in 22% (11/49) of older and in 48% (16/33) of younger patients ( P = .026 at chi-square). No major complications occurred during the procedu re. Pharmacological prophylaxis of AF recurrences was instituted immediatel y following the procedure. During inhospital stay and during the follow-up (mean 12 +/- 9 months for older patients and 15 +/- 10 months for younger p atients), AF recurred in 39% (17/44) of older patients and in 16%, (5/31) o f younger subjects (P = .064 at chi-square). CONCLUSIONS: Internal low energy cardioversion is a very effective procedur e For restoring sinus rhythm in patients with AF; it can be performed in ol der patients, and administration of sedatives or anesthetics can be avoided or minimized in a substantial proportion of subjects. Recurrences of AF in the long term tend to be higher in older subjects and intensive prophylaxi s with antiarrhythmic drugs is required.