BACKGROUND: The distribution of activated partial thromboplastin time (APTT) in 
nonvalvular atrial fibrillation (NVAF) patients under dabigatran therapy remains 
to be clarified.
METHODS AND RESULTS: The study population was 196 NVAF patients who were treated 
with dabigatran in 2011 (126 with 220 mg/day). The APTT values showed a wide 
distribution among the patients, especially in those with a reduced dose, who 
seemed to show a high value even in patients without contraindications.
CONCLUSIONS: We found a wide distribution of APTT in NVAF patients under 
dabigatran treatment. High APTT might help screen for bleeding risks among 
patients under dabigatran, but requires future investigation.