Frequent Premature Atrial Contractions in Stroke of Undetermined Etiology

BACKGROUND: The cause of ischemic stroke is undetermined in 15-40% of patients. We studied the association between frequent premature atrial contractions (PAC) and stroke of undetermined etiology. METHODS: We retrospectively studied ischemic stroke patients who were consecutively admitted to our department and underwent 24-hour Holter ECG recording including 163 noncardioembolic stroke patients (group A), 24 stroke patients of undetermined etiology (group B), and 37 cardioembolic stroke patients with prior-diagnosed paroxysmal atrial fibrillation (group C). The number of PAC per 24 h and the prevalence of patients with frequent PAC (200 or more per 24 h) were compared between the groups. RESULTS: The number of PAC was significantly larger in groups B and C than in group A. The proportion of patients with frequent PAC was larger in group B (13/24, 54%) and in group C (18/37, 48%) than in group A (32/163, 20%). CONCLUSION: Our data suggest that frequent PAC should be regarded as a masked type of paroxysmal atrial fibrillation and should be included in one of the causes of cardioembolic stroke.