Radiofrequency Catheter Modification of Atrioventricular Junction in Patients With COPD and Medically Refractory Multifocal Atrial Tachycardia

Multifocal atrial tachycardia (MAT) is adifficult clinical problem generally associated with acutecardiorespiratory illness. The purpose of this study was to assess thefeasibility and clinical usefulness of atrioventricular (AV) junctionmodification as a nonpharmacologic therapy for medically refractoryMAT. Thirteen patients withCOPD and medically refractory MAT underwent AV junction modification. Complications and outcome of this procedure were monitored. Subjectiveperceptions of quality of life assessed by a semiquantitativequestionnaire and cardiac performance study were obtained beforeablation (baseline) and 1 and 6 months after ablation. Radiofrequencyenergy was applied until the average ventricular rate fell to < 100beats/min. Ablation procedures controlled the ventricular response in11 of 13 patients (84%). One patient had unsuccessful modification.Another patient developed delayed complete AV block on the second dayafter ablation. In these 13 patients, average ventricular rate wasreduced from a mean of 145 ± 11 to 89 ± 22 beats/min immediatelyafter the ablation (p < 0.01). One patient had recurrent symptomaticMAT at 1 month after ablation; this patient underwent a secondprocedure without late recurrence. All patients were followed up for atleast 6 months (mean, 11 ± 5 months; range, 6 to 18 months). Generalquality of life and frequency of significant symptoms improvedsignificantly in patients with successful modification at 1 and 6months. The left ventricular ejection fraction increased significantlyafter ablation (44.5 ± 7.3% at baseline, 49.4 ± 4.2% at 1month, and 50.0 ± 4.9% at 6 months; all p < 0.05). However, right ventricular ejection fraction remained unchanged (34.7 ± 6.2%at baseline, 35.7 ± 4.4% at 1 month, and 34.3 ± 4.6% at 6months; all p > 0.05). The consumption of health-care resources(including frequency of hospital admission and emergency departmentattendance, antiarrhythmic drug trials) decreased significantly 6months after AV junction modification. Pulmonary function andtheophylline level remained unchanged during follow-up. AV junction modification offers an effectivetherapy for controlling ventricular rate in medically refractory MAT.This procedure improves the quality of life and left ventricularfunction in selected patients with symptomatic and medically refractoryMAT.