High energy transcatheter cardioversion for chronic, poorly tolerated atrial fibrillation.

Between August 1991 and May 1993, 14 patients affected by chronic, poorly tolerated atrial fibrillation (AF) were submitted to high energy transcatheter cardioversion. Mean duration of AF was 27.4 +/- 45.1 months. In nine patients (56%), AF lasted for > 1 year. All patients had underlying heart disease, with a mean LVEF of 45.2% +/- 11.8% and a NYHA Class > or = II. Previously, a mean of 2.9 +/- 1.3 patients failed external electrical cardioversion, with and without antiarrhythmics, have been attempted. Transcatheter conversion was performed by pulling the His-bundle catheter back in the right atrial cavity until no His bundle activity was recorded on distal poles, and then delivering the shock between a proximal electrode (cathode) and a back plate (anode). In all patients, transcatheter conversion restored sinus rhythm. Transient complete atrioventricular (AV) block was observed in four patients (28%), and treated by prophylactic temporary pacing. At 1 year, seven patients (50%) were still in sinus rhythm. In this series, only younger age could be related to AF recurrence (46.1 +/- 10.8 vs 63.4 +/- 6.8 years, P < or = 0.004), even if prophylaxis with amiodarone showed a positive trend versus sinus rhythm maintenance (71% vs 14%, P = NS). In conclusion, high energy transcatheter cardioversion is a safe and effective method of restoring sinus rhythm in patients with chronic, poorly tolerated AF. In these patients, high energy transcatheter cardioversion could be considered as an alternative to AV node ablation techniques, avoiding pacemaker implant and embolic risk. Larger studies are needed to determine better patient selection and delineate drug strategy after the procedure.

Myocardial dissection following successful chemical ablation of ventricular tachycardia.

We describe a case of fatal myocardial rupture and tamponade following a successful transcoronary chemical ablation of incessant ventricular tachycardia. Pathological examination showed a subepicardial dissection of the heart at the ablation site with fibrous and fatty degeneration of the myocardium. The present report calls for caution, underlying a possible lethal complication of ethanol ablation which has not been described before.

[Pharmacokinetics of amiodarone in one case of acute oral intoxication]. / Farmacocinetica dell'amiodarone in un caso di intossicazione acuta (8 grammi per os).

A wealth of data about the clinical use and the therapeutic efficacy of chronic treatment with amiodarone has been reported, while the acute effects of this agent are less known. In one case of acute oral intoxication with 8 g of amiodarone for suicidal purposes, we have investigated the pharmacokinetics of amiodarone, the thyroid function and the variations of some clinical parameters, such as heart rate and QT interval. Other possible side-effects have been looked for. We have not observed substantial pharmacokinetic differences between our case and studies carried out after chronic oral or intravenous administration. Unlike chronic administration, the acute oral load was not followed by the appearance of toxic effects. The absence of toxic phenomena can be explained by the poor bioavailability of amiodarone, which is known to require long periods for a complete distribution to the tissues and target organs.