Atrial Fibrillation: A Riddle Wrapped in a Mystery Inside an Enigma

[First paragraph] Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice with an estimated 20.9 million men and 12.6 million women living with AF worldwide.1 With almost 5 million new cases of AF annually, an estimated 1 in 4 individuals aged 40 years old of European descent will ultimately develop AF.2 Atrial fibrillation is associated with a 4-fold increased risk of stroke3 and a more than 2-fold increased risk of heart failure (HF)4 and mortality.5 AF is a common comorbidity in patients hospitalized with many cardiovascular conditions and is increasingly encountered in the growing elderly population in this arena.