Atrial fibrillation and sudden cardiac death: a mystery to be solved?

Atrial fibrillation has been associated with stroke, heart failure and cardiovascular mortality. Although several studies have recently put forward a connection between atrial fibrillation and sudden cardiac death, whether the arrhythmia should be regarded as an independent predictor of potentially harmful ventricular tachycardias is not utterly clear. Nor have the underlying mechanisms been thoroughly investigated yet. A cause-effect relationship seems to be involved in some cases. In other clinical scenarios, however, atrial fibrillation could be a mere expression of the severity of the underlying structural or electrical heart disease, therefore playing an unremarkable pathophysiologic role in this setting. Moreover, despite some exceptions, current guidelines do not provide a straightforward approach to identify which patients with atrial fibrillation bear a greater risk of sudden cardiac death. The aim of this review is to discuss the available clinical evidence in this field, suggesting a pathophysiologic sequence and a patient-tailored approach for an effective risk stratification and management of patients with atrial fibrillation.