Transtelephonic ECG Monitoring for Detecting Arrhythmia Recurrences After Radiofrequency Ablation
Abstract & Commentary
With Comment by John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville, Editorial Board, Clinical Cardiology Alert.
Synopsis: Routine daily transtelephonic ECG monitoring detects often asymptomatic arrhythmia episodes in a significant proportion of patients after radiofrequency ablation.
Source: Senatore G, et al. J Am Coll Cardiol. 2005;45:873-876.
In this study, Senatore and colleagues use transtelephonic monitoring to survey patients for recurrent atrial fibrillation after radiofrequency ablation procedures. Senatore et al identified 72 patients who underwent catheter ablation for atrial fibrillation. The ablation procedure involved isolation of the pulmonary veins and, in many patients, placement of adjunctive ablation lines in the left and/or right atria, along the cavotricuspid isthmus and between the mitral annulus and the left inferior pulmonary vein. After the procedure, 49 patients were maintained on amiodarone and 23 patients were maintained on flecainide. Patients were seen 7, 14, 30, and 120 days after the procedure. Arrhythmias in the first 30 days after ablation were not counted. At the 30-day visit, each patient received a transtelephonic ECG recorder and obtained and transmitted a daily 30 second ECG sample for the next 90 days. Additional ECG transmissions could be made if symptomatic palpitations occurred. Twenty-four hour Holter recordings were performed at the 30-day visit and 120 days after ablation.
The study group included 43 men and 29 women with a mean age of 62 + 9.1 years. Thirty-seven patients had paroxysmal AF and 35 patients had persistent AF. Hypertension was the most common cardiac diagnosis present in 42 patients. Twenty-two patients had no structural heart disease. During follow-up, a total of 288 standard ECGs, 144 twenty-four hour ambulatory ECGs, and 5585 transtelephonic ECG recordings were obtained. Standard ECG and Holter recordings detected recurrent arrhythmias in 10 patients (13.9%). During transtelephonic ECG recording, 20 patients (27.8%) had atrial arrhythmia recurrence. Many of the episodes detected by transtelephonic ECG did not produce symptoms, and 8 patients with documented recurrence were completely asymptomatic.
Senatore et al conclude that routine daily transtelephonic ECG monitoring detects often asymptomatic arrhythmia episodes in a significant proportion of patients after radiofrequency ablation. They stress that the inability to exclude recurrence of asymptomatic atrial fibrillation has important implications in terms of discontinuation of anticoagulation in patients who are at increased risk of stroke.
Comment
One of the reasons why many people elect to undergo treatment to maintain sinus rhythm is the hope that they can avoid long-term anticoagulation. Randomized clinical trials comparing rate control and rhythm control strategies have shown that with antiarrhythmic drug therapy, the incidence of stroke is not eliminated. In particular, patients who discontinue warfarin, because drug therapy is thought to be effective, appear to be at increased risk. Long-term data about the effects of catheter ablation of atrial fibrillation on stroke risk are, at present, unavailable. Many of the patients who have undergone the procedure in the past are at relatively low risk, and the careful natural history studies needed to estimate the incidence of stroke after catheter ablation have not even been begun. It is known, however, that in patients with other risk factors, even paroxysmal and asymptomatic episodes of atrial fibrillation, place them at increased stroke risk. The data by Senatore et al, therefore, are of concern. They noted that 15% of their patients had episodes of atrial fibrillation only detected by transtelephonic monitoring, and that in half of these patients, the episodes were free of symptoms. Since the recording was only obtained during 30 seconds of the day, one must assume that there were other patients with asymptomatic episodes, in whom a recording was not made.
For the present time, management of anticoagulation after catheter ablation for atrial fibrillation remains uncertain. The most conservative, and probably the safest approach, is to just continue anticoagulation in those patients who have an indication for it. This would be based on the admittedly conservative assumption that they may be having at least infrequent episodes of recurrent atrial fibrillation.
Routine daily transtelephonic ECG monitoring detects often asymptomatic arrhythmia episodes in a significant proportion of patients after radiofrequency ablation.
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