The purpose of this study is to determine the frequency of atrial fibrillation in patients with transient ischemic attack (TIA). Patients suffering TIA will have their heart rhythm extensively monitored with 72-hour Holter-monitoring and an implantable loop-recorder. Furthermore, the patients will be examined with echocardiography, coronary calcium-score and biomarkers with the purpose to predict which subjects at risk for developing atrial fibrillation.

Stroke is a leading cause of death and the survivors are often left with severe disability. Transient ischemic attack (TIA) is an episode of neurological dysfunction, but unlike stroke, the neurological deficits resolve completely within 24 hours. TIA and stroke share the same common underlying cause, and patients with a TIA are at high risk for developing a subsequent stroke. Atrial fibrillation (AF) is the most common cardiac arrhythmia and is recognized as the cause of around 25% of all strokes. The prevalence of AF rises with age, and it is estimated, that approximately 5-10% of all subjects over the age of 80 years has either persistent or paroxysmal AF. Regardless of the AF subtype the risk for stroke is the same, and oral anticoagulation therapy is recognized as a superior treatment of AF related stroke/TIA.

The goal of this project is to extend the normal workup of patients with TIA with a thorough heart monitoring program. This includes 72-hours ambulatory electrocardiogram and insertion of an implantable loop recorder (ILR). The ILR is small device implanted in the subcutaneous tissue in the left thoracic region. The device continuously monitors for arrhythmias in a period up to 3 years. The 150 patients enrolled will also receive an ultrasound examination of the heart and arteries of the neck and a computed tomography scan of the heart. Lastly, biomarkers with known or suspected association with stroke and AF will be measured.

The primary goal of the study is to determine, whether or not an extended heart monitoring program with an ILR will identify more patients with AF as the underlying cause of TIA. This can have enormous advantages for the patient, because the treatment with oral anticoagulation therapy reduces the risk of subsequent stroke by approximately 40% compared to conventional antiplatelet therapy. Secondly, the study means to identify patients at high risk for developing AF assessed with ultrasound, computed tomography and novel biomarkers.

Inclusion Criteria:

• Diagnosed with TIA by a board certified neurologist
• Written consent
• Residents of Funen, Denmark or surrounding islands

Exclusion Criteria:

• Prior stroke
• Known atrial fibrillation
• Known contraindication for anticoagulant therapy
• Patients already in anticoagulant therapy
• Patients with estimated short life expectancy
• Pregnancy
• Prior TIA with known etiology