Background: The implantable loop recorder (ILR) could provide the highest possibility to detect AF than any other modality, but it is invasive and costly. The purpose of this study is determined the accuracy of ILR to detecting early recurrence of AF within 3 months after catheter ablation (CA).
Method: A total of 51 patients (paroxysmal AF=31, persistent AF=20) who underwent CA for AF were enrolled. All of them were scheduled to have 24-Hours Holter monitoring at 48 hours, 4, 8 and 12weeks after the procedure. They were assigned to two concomitant monitoring randomly; smartphone based ECG monitoring (SEM) in 32 patients and ILR in 19 patients. SEM group was recommended to send the recording for an hour at a certain time of the day or when they had symptoms. ILR was programmed routinely and interrogated at the same time of Holter.
Results: The total number of 189 Holter monitorings, concomitant 122 SEM recordings, and 67 ILR recordings were available for comparison. Early recurrence was defined as any atrial tachyarrhythmia (AT) of more than 30 seconds within 3 months after catheter ablation. In SEM group, the early recurrence rate in the Holter was 44% and 63% in SEM. In ILR group, the early recurrence rate in Holter was 53% and 63% in ILR. The overall detection rate of early recurrence with the Holter was 41%, and other modalities was 73%. For the evaluation of the accuracy of ILR, interrogated data on the day from Holter monitor was analyzed. ILR and Holter did not coincide significantly (kappa=0.385, p=0.002, Table.1).
Conclusion: The ability to detect the early recurrence in the same patient is significantly higher in frequent or continuous monitoring than 24 Holter monitoring. However, the detection algorithm of ILR should be taken into consideration when evaluating the AF recurrence.