Prediction and detection of occult atrial fibrillation in patients after acute cryptogenic stroke and transient ischemick attack. The PROACTIA study

Abstract

This is a clinical study of patients after cryptogenic stroke (stroke of unknown cause) treated at the Department of Neurology and the Department of Cardiology at Akershus University Hospital (AHUS). Loreta Skrebelyte-Strøm and colleagues have developed a clinical score, based on ECG, 24-hours ECG recording and cardiac ultrasound to identify patients who has highest risk of underlying hidden atrial fibrillation, one of the most important risk factors for blood clots in the heart and stroke. Hidden atrial fibrillation was identified using cardiac monitors, implanted under the skin of the study participants and with an ability to record and interpret the heart rhythm continuously for up to three years. The clinical score was able to select patients with the highest and lowest risk of atrial fibrillation. This is important because those who have hidden atrial fibrillation should be treated with another type of blood-thinning medication to prevent recurrence of stroke. The researchers have also performed and analyzed ultrasound of the heart using new methods such as strain, mechanical dispersion and three-dimensional ultrasound. Strain and mechanical dispersion are ultrasound methods that measures the contraction pattern of the left atrium and can detect reduced function. This method has previously been shown to be associated with the risk of clinical atrial fibrillation. In this study, the researchers have for the first time applied strain and mechanical dispersion on the left atrial appendage in patients after cryptogenic stroke and shown that this method could be able to predict the risk of hidden atrial fibrillation and blood clot formation in the left atrium auricle. They have also demonstrated by using three-dimensional cardiac ultrasound, that patients with a special auricular morphology («chicken wing») have the highest risk of developing blood clots in the left atrial appendage.