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Smartphone AF Burden During Blanking Period Predicts Ablation Outcomes
Quick Takes
- Smartphone-based ECGs can be used to detect atrial fibrillation (AF) recurrence following an AF ablation.
- AF burden, derived from smartphone ECG strips during the post-ablation blanking period, predicts long-term risk of recurrent atrial arrhythmias.
- High AF burden during the post-ablation blanking period is strongly correlated with high AF burden after the blanking period with the latter associated with adverse clinical outcomes.
Study Questions:
During the blanking period following AF ablation, does AF burden, as measured by a single-lead electrocardiogram (ECG) from a smartphone, predict longer-term catheter ablation outcomes?
Methods:
The authors performed a retrospective analysis of the DECAAF II (Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) trial, a prospective, multicenter, randomized controlled trial in which patients with persistent AF were randomized to magnetic resonance imaging (MRI)-guided fibrosis ablation with pulmonary vein isolation (PVI) or PVI alone. Following their ablation, participants received a handheld smartphone ECG and were asked to record daily 30-second ECG strips in addition to obtaining ECG strips for symptoms. AF burden during the blanking period (i.e., days 1-90 post-ablation) was defined as the ratio of ECG strips with AF to the total number of ECG strips obtained during that time period. The primary outcome of the study was defined as the first confirmed recurrence of an atrial arrhythmia after the 90-day blanking period.
Results:
Included in the analysis were 630 of 843 DECAAF II participants, of whom 301 (47.8%) experienced recurrent atrial arrhythmias from the end of the blanking period until the end of study follow-up. Participants submitted 0.91 strips/day on average during the 90-day blanking period. Participants who experienced a recurrent atrial arrhythmia had an AF burden of 31.3% during the blanking period, while those who did not have a recurrence had an AF burden of 7.5% during the blanking period (p < 0.001).
In a Cox proportional hazards model adjusting for demographic and clinical characteristics, AF burden during the blanking period was independently associated with risk of recurrent arrhythmias after the blanking period (hazard ratio [HR], 1.41; 95% confidence interval [CI], 1.36-1.46; p < 0.001, for every 10% increase in burden). An AF burden of 18% demonstrated the highest discriminatory value with a c-index of 0.748. Over 18-month follow-up, atrial arrhythmias recurred in 33.7% of participants with AF burden <18% and in 79.4% with an AF burden >18% (HR, 4.57; 95% CI, 3.63-5.75; p < 0.001). AF burden during and after the blanking period was highly correlated.
Conclusions:
AF burden from smartphone ECGs obtained during the post-AF ablation blanking period predicts risk of recurrent atrial arrhythmias. AF burden during the blanking period is strongly correlated with AF burden following the blanking period.
Perspective:
There has been exponential growth in the use of mobile health technologies for arrhythmia detection and ECG monitoring. To date, most studies have focused on using these tools to detect incident AF with a lesser focus on using them for chronic arrhythmia management. This retrospective analysis of the DECAAF II trial thus adds to the existing literature by demonstrating how patient-initiated ECGs can be used effectively for AF surveillance. By using such an approach, the study investigators were able to detect AF recurrence and quantify AF burden post-ablation. It is unknown yet, however, whether such a strategy can be used to guide subsequent medication management. Additionally, while such a strategy offers promise, it is premature to implement such a strategy in clinical practice using patients’ own smartwatches. Prior to implementation, workflows need to be established to collect and review the data in a manner that does not overwhelm clinician resources.
Clinical Topics: Arrhythmias and Clinical EP, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias
Keywords: Atrial Fibrillation, Catheter Ablation, Smartphone
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