Total atrial conduction time to predict occult atrial fibrillation after cryptogenic stroke

Insertable cardiac monitor (ICM) increases the detection rate of occult atrial fibrillation (AF) after cryptogenic stroke. The aim of this study was to evaluate the prognostic significance of total atrial conduction time (TACT) assessed by tissue Doppler imaging (PA-TDI interval) to predict AF presence in patients with cryptogenic stroke.

Ninety patients (57.7 ± 12.3 years, 48 % women) after acute cryptogenic stroke and ICM implantation were prospective recruited at four centers for continuous rhythm monitoring. In all patients, TACT was measured by PA-TDI interval via echocardiography. Patients were followed up (331 ± 186 days) for detection of AF (defined by episode lasting ≥30 s).

AF was detected in 16 patients (18 %) during follow-up (331 ± 186 days). The median period to AF detection was 30 days (q1-q3; 16-62 days). Patients who exhibited occult AF were characterized by significantly longer PA-TDI intervals (154.7 ± 12.6 vs. 133.9 ± 9.5 ms, p < 0.0001). The cut-off value of PA-TDI interval at 145 ms demonstrated sensitivity and specificity for AF detection of 93.8 and 90.5 %, respectively. In multivariate analysis, CHA2DS2-VASc score (HR 1.96 per 1 point, p < 0.01) and longer PA-TDI interval (HR 4.05 per 10 ms, p < 0.0001) were independent predictors of occult AF.

Our data suggest that measurement of TACT could help to predict future AF detection in patients with cryptogenic stroke. The clinical importance of prolonged rhythm monitoring or indication of direct anticoagulation therapy after cryptogenic stroke based on TACT should be further investigated.