Page 12 - ADD-ON ABLATION SURGERY IN PATIENTS WITH ATRIAL FIBRILLATION

Chapter 1
Atrial fibrillation
Incidence, prevalence and natural history of atrial fibrillation
Atrial fibrillation (AF) is the most common cardiac rhythm disturbance seen in clinical practice accounting for approximately one-third of hospitalizations1.
The estimated prevalence of AF is 0.4–1% in the general population, increasing with age2,3 and it is associated with a higher long-term risk of stroke, heart failure and all cause mortality, especially in women4,5.
It is commonly associated with a number of cardiac and non-cardiac risk factors including ischaemic heart disease, cardiac failure, valvular heart disease, hypertension, diabetes, alcohol abuse, thyroid disorders and pulmonary disease 6,9. AF is common in patients who undergo valvular and/or coronary bypass surgery (5-40%) as a result of underlying heart disease and age. It induces aggravating symptoms, impairs cardiac performance due to loss of effective atrial contraction and can lead to heart failure and stroke. Nonetheless, in a non-negligible percentage of people presenting with AF, there is no identifiable aetiology and this subset of patients is often referred to as ‘lone AF’ (LAF) 10.
ACC/AHA/ESC guidelines11 applied the term LAF to ‘... individuals younger than 60 years without clinical or echocardiographic evidence of cardiopulmonary disease, including hypertension’. A recent international consensus on nomenclature and classification of AF mentions that only AF in the absence of heart disease is termed ‘lone’ while in the absence of any disease is termed ‘idiopathic’12. Indeed, LAF does not necessarily mean ‘idiopathic’. In addition, in recent years, an increasing body of evidence has indicated several novel epidemiological and pathophysiological associations of AF. It could therefore be hypothesized that many of the recorded lone or idiopathic AF cases are linked to other not well-known factors. However, the diagnosis of LAF is essentially a diagnosis of exclusion, and should be preceded by careful evaluation, including a thorough collection of the patient’s medical history, physical examination, blood pressure measurement, laboratory tests, ECG, echocardiography and, according to some experts, chest X-ray and exercise testing11.
Among that group,LAF occurs in 1.6 to 11.4% of all cases ofAF13-15.However,theALFA study (Etude en Activité Libérale de la Fibrillation Auriculaire) reports the proportion of LAF among all cases of AF to be over 30%16. In other epidemiological studies LAF was reported to occur in a percentage ranging between 1.9% and 32%17-19. Epidemiological data show a male predominance in patients with LAF, since men
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