Right and left atrial radiofrequency catheter therapy of paroxysmal atrial fibrillation.

INTRODUCTION: Atrial fibrillation (AF), the most common arrhythmia, is due to multiple simultaneous wavelets of reentry in the atria. The only available curative treatment is surgical, using atriotomies to compartmentalize the atria. Therefore, we investigated a staged anatomical approach using radiofrequency catheter ablation lines to prevent paroxysmal AF.

METHODS AND RESULTS: Forty-five patients with frequent symptomatic drug-refractory episodes of paroxysmal AF were studied. Progressively complex linear lesions were created by sequential applications of radiofrequency current in the right atrium and then in the left atrium if required. The outcome of the procedure was considered a success when the episodes of AF were either eliminated or recurred at a rate of no more than one episode (lasting < 6 hours) in 3 months. Patients who had no more than one episode per month were considered "improved." Right atrial ablation organized local electrical activity and led to stable sinus rhythm during the procedure in 18 (40%) of the 45 patients. However, sustained AF remained inducible in 40 of 45 patients, and the lesions failed to produce evidence of a significant linear conduction block/delay in all but four patients. There were no significant complications except for two transient sinus node dysfunctions. The procedure duration and fluoroscopic time were 248 +/- 79 and 53 +/- 22 min, respectively. Additional sessions were required in 19 patients to treat sustained right atrial flutter or arrhythmias linked to ectopic right or left atrial foci. During a mean follow-up of 11 +/- 4 months, right atrial ablation was successful in 15 (33%) patients, 6 without medication and 9 with a previously ineffective drug. Nine (20%) additional patients were improved. Ten patients with an unsuccessful outcome then underwent linear ablation in the left atrium. The procedure duration and fluoroscopy time were 292 +/- 94 and 66 +/- 24 min. A hemopericardium occurred in one patient. Two patients required reablation to treat ectopic atrial foci. Left atrial ablation terminated AF during the procedure in 8 patients, and sustained AF could not be induced in 5. Subsequent success was achieved in 6 (60%) patients, including 4 without medication, and 1 additional patient was improved.

CONCLUSIONS: Successful radiofrequency catheter ablation of drug-refractory daily paroxysmal AF is feasible using linear atrial lesions complemented by focal ablation targeted at arrhythmogenic foci. Ablation only in the right atrium is a safe technique providing limited success, whereas linear lesions in the left atrium significantly increase the incidence of stable restoration of sinus rhythm, the inability to induce sustained AF, and the final success rate. The described technique is promising but must be considered preliminary because significant improvements are required to optimize lesion characteristics and shorten total procedure duration.