Introduction: Silent atrial fibrillation (AF) is a common cause of cryptogenic ischemic stroke (CIS). The 24-h-Holter is insufficient to reveal an occult arrhythmic cause of stroke and the strategy to select the patients for long-term monitoring is missing.
Objectives: The aim of the study was to evaluate 7-day-Holter monitoring to identify cases with the arrhythmic cause of stroke in CIS patients in whom 24-h-Holter was free from arrhythmia, and to assess the relation between supraventricular (SV) runs in baseline Holter and the incidence of AF in a 3-year follow-up period.
Methods: 78 patients (aged 60 ± 9 years, 45 males) with CIS and no arrhythmic findings in 24-h-Holter were enrolled. All patients had 7-day-Holter monitoring after stroke and were followed up for 36 months, and then 7-day Holter was repeated. We assessed SV runs (≥5 QRS) in the initial 7-day Holter and analyzed the relation of the findings with clinical characteristics of novel AF episodes revealed early after stroke and during a 3-year follow-up.
Results: Baseline 7-day-Holter revealed SV runs in 36% of patients and AF in 9% of cases. During a 3-year follow-up, 8 additional cases were confirmed, both in standard care and in repeated Holter (a total of 19% of AF cases). There was no difference with regard to CHADS2VASc score (3.6 ± 1.1 vs. 3.4 ± 1.5; p = NS) and left atrium parameters between patients with SV runs and the non-arrhythmic group. Patients with SV runs had a higher incidence of AF both after stroke and in a 3-year follow-up (46% vs. 4%, RR 11.6, p < 0.001). In 8 cases, patent foramen ovale was detected during follow-up.
Conclusions: A strategy of baseline 7-day-Holter monitoring after stroke allows for disclosing SV runs in every third case and AF in 9% of stroke survivors. Patients with SV runs have a higher incidence of AF (RR 11.6, p < 0.001) and should be considered for extended continuous ECG monitoring.
Keywords: Holter ECG; SV runs; atrial fibrillation; cryptogenic ischemic stroke; supraventricular arrhythmia.