Background: Cerebrovascular stroke is a major cause of morbidity and disability. Many etiologies may contribute to its presence. Some patients have none of the identifiable risk factors yet face the consequences of stroke or transit ischemic attack. This type of stroke is known as embolic stroke of undetermined source (ESUS). It has a high rate of recurrence due to the presence of an unknown uncorrected etiology. Paroxysmal atrial fibrillation remains a hidden bottom of an iceberg, representing a major hidden etiology of ESUS. We aimed to determine the prevalence of paroxysmal atrial fibrillation in patients with ESUS using 72?h Holter monitoring. 

Methods: Patients diagnosed with ESUS underwent 72?h Holter monitoring within the 1st week of the incident stroke. Holter monitors determined whether atrial fibrillation (more than 3 s) is present or not. 

Results: This study included 200 patients with stroke of an undetermined source who underwent 72?h Holter monitoring within 1 week of the incident stroke. The patients’ ages ranged between 22 and 77 years (mean age 48.46 ± 12.74 years); 136 were males and body mass index (BMI) ranged from 21 to 35 kg/m2 , with a mean BMI of 24.78 ± 2.99 kg/m2 . Their left atrial anteroposterior diameter in the parasternal long?axis view ranged from 26 mm to 47 mm, with a mean diameter of 36.08 ± 5.23 mm. Thirty?two out of the 200 patients were diagnosed with paroxysmal atrial fibrillation, representing 16%. There was a statistically significant association between the presence of paroxysmal atrial fibrillation and both age (P = 0.009) and left atrial diameter (P = 0.001). There was an associated finding that needs further investigation regarding the significant association between supraventricular ectopic beats and the presence of atrial fibrillation or stroke. 

Conclusion: Paroxysmal atrial fibrillation is an important hidden etiology of embolic stroke of undetermined etiology that can be detected early using 72?h Holter monitoring within 1 week of the incident strok

Cardiology Department, Faculty of Medicine