Q: What are the most important consequences of atrial fibrillation?
A: Atrial fibrillation is worrisome for its complications rather than for the arrhythmia itself. Indeed, importantly, since atrial fibrillation often occurs in association with other heart (cardiac) or extra-cardiac diseases (for example, valvular defects, heart chamber enlargement, coronary artery disease, diabetes, hypertension). Thus, the clinical evolution depends also on the so-called "co-morbidity morbidities" (i.e., the "other" heart diseases). Atrial fibrillation is a cause of cardiovascular complications (for example, it can aggravate heart failure), and it causes a reduction in tolerance to physical activity. However, the most severe complication is caused by stagnation of blood in the atrial chambers (due to the loss of coordinated contraction). This promotes the formation of blood clots (thrombi) on the walls of the atrium. If the blood clot detaches it is often dragged by the blood flow to the arteries of the brain (due to anatomical reasons) so they can become clogged causing a stroke. For this reason, patients with atrial fibrillation are commonly treated with anticoagulant drugs.