Prevalence of clinically significant bradyarrhythmias in patients implanted with loop recorders for cryptogenic stroke: A manifestation of atrial cardiomyopathy?

BACKGROUND

Cryptogenic stroke (CS) is often associated with atrial fibrillation (AF), but may also reflect a broader atrial pathology such as atrial cardiomyopathy. Although implantable loop recorders (ILRs) are used primarily to detect AF in these patients, the burden of bradyarrhythmias is not well established.

OBJECTIVE

This study aimed to evaluate the prevalence and clinical significance of bradyarrhythmias in patients implanted with ILRs after CS or transient ischemic attack (TIA) compared with a matched control population with ILRs for other indications.

METHODS

We retrospectively analyzed 225 patients receiving ILRs for CS/TIA (n = 139) or other indications excluding syncope (n = 86). Bradyarrhythmias were classified according to the European Society of Cardiology 2021 guidelines. A 1:1 propensity score matching was performed based on major covariates. The primary end point was the time to the first detection of clinically significant sinus node dysfunction (SND).

RESULTS

During a median follow-up of 23 months, SND occurred more frequently in the CS group than in controls (18.7% vs 4.7%; P = .003). After propensity score matching (n = 114), SND remained significantly more prevalent in patients with stroke (22.8% vs 8.8%; P = .04). Univariate analysis identified CS/TIA (odds ratio 3.14; 95% confidence interval 1.02-9.64; P = .045), hypertension, and increased indexed left atrial volume as independent predictors of SND. Kaplan-Meier analysis showed a significantly lower event-free survival for SND in the CS group (log-rank P = .034).

CONCLUSION

Patients with CS show a significantly higher and earlier incidence of clinically relevant SND than matched controls, which may suggest an underlying atrial remodeling process consistent with atrial cardiomyopathy. These findings underscore the importance of comprehensive arrhythmic monitoring beyond AF in this population.