DDD(R) pacing with automatic mode switch in patients with paroxysmal atrial fibrillation following AV nodal ablation.

Optimal pacing in patients with paroxysmal atrial fibrillation/flutter following AV node ablation remains to be determined because VVIR pacing cannot restore AV synchronization and conventional DDD(R) pacing cannot properly cope with atrial tachyarrhythmias. The objective of the present investigation was to study the clinical outcome of 16 of these patients who received a new DDDR pacemaker with an automatic mode switch (Thera DR; Medtronic) immediately after AV node ablation. Arrhythmia-related symptoms before ablation were palpitations in 12, dizziness in 10, exercise intolerance in 8, and syncope in 6 patients. Pacing modes at hospital discharge were DDDR (n = 14) and DDD (n = 2) with an activated mode switch in all patients. After 1 month 12 patients were symptom free. Clinical events occurred in 4 patients (palpitations in 2, dizziness in 1, chest pain in 1, and fatigue in 1), which could be relieved in 3 patients. At discharge as well as at the 1-month follow-up, Holter ECG recorded a total of 12 episodes of atrial fibrillation in 5 patients, which were correctly detected by the pacemaker and followed by mode switching. At the 3-month follow-up (n = 14), 12 patients were symptom free and 2 continued to report symptoms which could not be resolved. All patients remained on an automatic mode switch in either the DDDR (n = 12) or DDD (n = 2) mode. There were no hints of inappropriate mode switching or reports of pacemaker syndrome, and there were no new symptoms related to automatic mode switching. The patients studied were highly symptomatic before implantation due to paroxysmal atrial fibrillation/flutter. After the first follow-up, 81% of the patients reported no symptoms. Paroxysmal atrial fibrillation/flutter combined with a high-degree AV-block seems no longer to be a contraindication for AV-synchronous pacing.