Radiofrequency catheter modification of atrioventricular junction in patients with COPD and medically refractory multifocal atrial tachycardia

Background: Multifocal atrial tachycardia (MAT) is a difficult clinical problem generally associated with acute cardiorespiratory illness. The purpose of this study was to assess the feasibility and clinical usefulness of atrioventricular (AV) junction modification as a nonpharmacologic therapy for medically refractory MAT. Methods and results: Thirteen patients with COPD and medically refractory MAT underwent AV junction modification. Complications and outcome of this procedure were monitored. Subjective perceptions of quality of life assessed by a semiquantitative questionnaire and cardiac performance study were obtained before ablation (baseline) and 1 and 6 months after ablation. Radiofrequency energy was applied until the average ventricular rate fell to < 100 beats/min. Ablation procedures controlled the ventricular response in 11 of 13 patients (84%). One patient had unsuccessful modification. Another patient developed delayed complete AV block on the second day after ablation. In these 13 patients, average ventricular rate was reduced from a mean of 145 ± 11 to 89 ± 22 beats/min immediately after the ablation (p < 0.01). One patient had recurrent symptomatic MAT at I month after ablation; this patient underwent a second procedure without late recurrence. All patients were followed up for at least 6 months (mean, 11 ± 5 months; range, 6 to 18 months). General quality of life and frequency of significant symptoms improved significantly in patients with successful modification at 1 and 6 months. The left ventricular ejection fraction increased significantly after ablation (44.5 ± 7.3% at baseline, 49.4 ± 4.2% at 1 month, 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 6 months; all p > 0.05). The consumption of health-care resources (including frequency of hospital admission and emergency department attendance, antiarrhythmic drug trials) decreased significantly 6 months after AV junction modification. Pulmonary function and theophylline level remained unchanged during follow- up. Conclusions: AV junction modification offers an effective therapy for controlling ventricular rate in medically refractory MAT. This procedure improves the quality of life and left ventricular function in selected patients with symptomatic and medically refractory MAT.