Internal low-energy cardioversion: a therapeutic option for restoring sinus rhythm in chronic atrial fibrillation after failure of external cardioversion.

AIMS: Conventional external cardioversion remains the technique of choice for restoration of sinus rhythm in patients with chronic atrial fibrillation (AF). Recent reports have suggested that internal low-energy cardioversion is efficient and safe in terminating AF in patients with failed external cardioversion. METHODS AND RESULTS: In 20 of 118 consecutive patients with spontaneous chronic AF (>7/days), who underwent low-energy cardioversion, one or more attempts at restoring sinus rhythm with external cardioversion had failed. Low-energy internal cardioversion was performed under light sedation. Shocks were delivered (using an external custom defibrillator) between two nonapolar catheters positioned in the right atrium (cathode) and in the coronary sinus (anode). Heart disease was present in 12 and absent in eight patients ('lone' atrial fibrillation). Atrial fibrillation was established for a period ranging from 12 days to 53 months. Low-energy internal cardioversion restored sinus rhythm in 15 of the 20 patients (75%) with a mean energy of 4.5+/-1.2 J, a mean conversion voltage of 355+/-53 V and a mean impedance of 63+/-8 ohms. No complications were observed. With a mean follow-up of 6+/-7 months, 11 patients (73%) were in stable sinus rhythm. CONCLUSIONS: This study provides evidence in support of low-energy internal cardioversion as a valuable therapeutic option in patients in whom conventional external cardioversion failed. This technique is safe and does not require general anaesthesia.

[Atrial defibrillators or implantable atrioverters. Initial results]. / Défibrillateur auriculaire ou atrioverteur implantable. Premiers résultats.

The atrial defibrillator is a new non-pharmacological treatment of atrial fibrillation (AF) for restoration of sinus rhythm. This device has two programmable modes: automatic or activated by the physician or patient. In the automatic mode, the device delivers a shock synchronous with the R wave to restore sinus rhythm when AF is detected. Two patients with paroxysmal AF resistant to pharmacological therapy were included in a study to assess the efficacy and safety of the atrial defibrillator in the mode activated by the physician. The device implanted in the pectoral region is connected to 3 electrodes, two for atrial defibrillation and sensing positioned in the coronary sinus and right atrium respectively and a sensing and pacing electrode in the right ventricle. The right ventricle is paced if a post-shock pause is detected. It is possible to interrogate the device with a programmer using its Holter function and so determine the number of episodes of AF sensed and treated. The number, intensity and energy of the shocks and the parameters of ventricular stimulation are programmable. In these two patients, the atrial defibrillator effectively reduced prolonged episodes of AF with a follow-up of 12 and 7 months. No pro-arrhythmic effects were observed. Further clinical evaluation is under way to assess this new mode of treatment, including the mode activated by the patient, safety and tolerance of the shocks. In our two patients, the treatment of prolonged episodes of AF was followed by reduction of many short or asymptomatic episodes.

Transvenous cardioversion of atrial fibrillation using low-energy shocks.

Recent reports have suggested that transvenous cardioversion of atrial fibrillation is feasible using low-energy shocks and a right atrium coronary sinus electrode configuration. We evaluated in a prospective study the efficacy and safety of low-energy internal cardioversion of atrial fibrillation in 104 consecutive patients. Sixty-two patients presented with chronic atrial fibrillation (group I), 16 had paroxysmal atrial fibrillation (group II), and 26 had an induced atrial fibrillation episode (group III). The mean duration of the presenting episode of atrial fibrillation was 9 +/- 19 months for group I, 4 +/- 2 days for group II, and 18 +/- 7 minutes for group III. Atrial defibrillation was performed using two intracardiac catheters: one was placed in the right atrium (cathode) and the other in the coronary sinus or in the left branch of the pulmonary artery (anode). The catheters were connected to a customized external defibrillator capable of delivering 3/3-ms biphasic waveform shocks with a voltage programmable between 10 and 400 volts. The shocks were synchronized to the R wave. Sinus rhythm was restored in 44 of the 62 patients in group I (70%), in 12 of the 16 patients in group II (75%), and in 20 of 26 patients in group III (77%). The mean voltage and energy required for cardioversion were respectively 300 +/- 68 V and 3.5 +/- 1.5 J, for group I, 245 +/- 72 V and 2.0 +/- 0.9 J for group II, and 270 +/- 67 V and 2.6 +/- 1.2 J for group III. The leading-edge voltage required for sinus rhythm restoration was significantly higher (p < 0.05) in the chronic atrial fibrillation group than in the paroxysmal or induced groups. No proarrhythmic effects occurred for the delivered 686 R-wave synchronized shocks. This study of a large group of patients confirms and extends the results of previous reports. Such findings may have clinical implications for elective cardioversion of atrial fibrillation and the development of an implantable atrial defibrillator.

[Cardioversion of atrial fibrillation with low energy internal electric shock]. / Cardioversion par choc électrique interne à basse énergie de la fibrillation auriculaire.

The efficacy and safety of low internal cardioversion for the reduction of atrial fibrillation was assessed prospectively in 104 consecutive patients. Sixty-two patients had chronic atrial fibrillation (Group I). 16 patients had paroxysmal atrial fibrillation (Group II) and 26 patients had induced atrial fibrillation (Group III). The average duration of the current episode of atrial fibrillation was 9 +/- 19 months in Group I, 4 +/- 2 days in Group II and 18 +/- 7 minutes in Group III. Two intracardiac defibrillation catheters were used, one (the cathode) in the right atrium and the other in the coronary sinus or left branch of the pulmonary artery (anode). These catheters were connected to an external defibrillator delivering biphasic 3/3 ms shocks with a voltage which could be programmed from 10 to 400 volts. The shocks were synchronised on the R wave. Sinus rhythm was restored in 44 of the 62 patients in Group I (70%), 12 of the 16 patients in Group II (75%) and 20 of the 26 patients in Group III (77%). The average voltages and energies restoring sinus rhythm were 300 +/- 68 volts and 3.5 +/- 1.5 joules respectively in Group I, 245 +/- 72 volts and 2.0 +/- 2.9 joules in Group II, and 270 +/- 67 volts and 2.6 +/- 1.2 joules in Group III. These results show that the energy required to restore sinus rhythm is significantly greater in patients with chronic atrial fibrillation than in patients with paroxysmal or induced atrial fibrillation. There were no ventricular proarrhythmic effects in the 686 shocks synchronised on the R wave. This study shows that internal cardioversion of atrial fibrillation is feasible with low energies under simple sedation. These results support the concept of an implantable atrial defibrillator.

Incidence of perforation and other mechanical complications during dual active fixation.

The intraoperative and early postoperative mechanical complications of a procedure combining an atrial screw-in lead and a ventricular screw-in lead insertion were prospectively evaluated. The procedure was performed in 119 consecutive patients (mean age 69 +/- 8 years), at first implant in 100 patients and at reoperation in 19. Nine patients had previously undergone cardiac surgery and three underwent transvenous ventricular defibrillator implantation. The double sets of leads were introduced through 2 separate veins in 5 cases, through a single venous route in 114 cases, using a percutaneous approach in 75 cases and a venous cutdown in 49, and a guidewire procedure following the venotomy in 19. The screw was mannitol coated in 102 cases, exposed in 111, and extendable/retractable in 25. The fixation of the ventricular lead was performed at the apex in 108 cases, at the outflow tract in 11, and was followed by the fixation of the atrial lead at the appendage in 112 cases and at the lateral wall in 7 cases. The lead positioning and fixation were successful at first attempt in 103 cases and after repeated lead manipulation in 19 cases. The rotational torque could be transferred to the helix in all cases except in one patient who required a second vein puncture. Unintentional fixation in the ventricular chamber with subsequent failure to remove the lead occurred in one patient. Reoperation for lead dislodgment was required in two patients. In one patient, symptomatic pericarditis with pericardial effusion was observed 1 day after the procedure and resolved spontaneously. Dual active fixation is feasible with a low incidence of mechanical complications.

[Use of percutaneous anesthesia in cardiac pacemaker implantation]. / Emploi de l'anesthésie transcutanée dans les procédures d'implantation de stimulation cardiaque.

OBJECTIVES: Assess the efficacy of an anesthesic cream for pacemaker implantations. METHODS: Percutaneous anesthesia was studied in a series of permanent pacemaker transvenous implantations. The anesthesic cream composed of a mixture of lidocaine and prilocaine was applied precisely over operative areas after marking the skin. Percutaneous anesthesia should be applied 2 hours before entering the operating room. RESULTS: This percutaneous local anesthesia was perfectly effective for simple replacement procedures. At first implantations, it was used alone in 4 out of 10 cases while intradermal injections were needed to anesthetize the deep layers in the other patients. Serum concentrations indicate very low levels which are tolerated very well. CONCLUSION: Alone or combined with lidocaine infiltration, the use of an anesthesic cream is safe and effective in transvenous pacemaker surgery.