The heart and brain imaging in lone atrial fibrillation - are we surprised?

"Lone" atrial fibrillation (AF) is generally used to refer to patients with AF in the absence of structural heart disease. When the decision for oral anticoagulation is discussed, "lone" AF refers to patients who do not have established stroke risk factors. Imaging is often used to rule out structural heart disease, e.g. coronary artery disease, peripheral vascular disease, mitral stenosis or left ventricular (LV) dysfunction. Imaging of the heart has a central role in establishing the "lone" aspect in patients with "lone"AF, similar to the measurement of blood glucose and blood pressure: Patients with structural heart disease, defined as e.g. reduced LV ejection fraction, clinical evidence for heart failure, or evidence for coronary artery disease, will not be considered as patients with "lone" AF. The search for these conditions requires some cardiac imaging, often done by echocardiography and non-invasive tests for coronary artery disease or ischemia. Increasingly, brain imaging is used to define the clinical diagnosis of a stroke, thus also contributing to the detection of stroke risk factors. Cerebral imaging in AF patients without competing causes for silent strokes or microbleeds ("lone" AF, rather used in the context of anticoagulation, i.e. clinical absence of structural heart disease) would allow to better understand the contribution of AF to these brain lesions. The assumption that silent strokes are likely drivers of cognitive dysfunction, and the fact that microbleeds put patients at risk for intracerebral hemorrhage, illustrates the need to collect information on brain imaging. In this review article, we summarize current data on heart and brain imaging in patients with "lone" AF and discuss their clinical implications for risk assessment and management of patients with "lone" AF.