MEDICAL PROFESSIONALS

Disease State

Pathophysiology of Afib

Left unchecked, Afib can have a profound impact on cardiac function and physiology, decreasing cardiac output and increasing vascular resistance.Adequate treatment of Afib is essential not only to control symptoms and reduce the risk of thromboembolic events, but also to minimize irreversible cardiac remodeling.

The onset of Afib rapidly triggers electrical remodeling, potentially leading to structural remodeling, fibrosis, and chronic Afib. In the long-term, the onset of Afib can establish a vicious cycle involving electrical, contractile, and structural remodeling: electrical remodeling promotes further atrial fibrillation, leading to its maintenance, which in turn leads to structural changes including irreversible fibrosis. Progressive fibrosis isolates muscle bundles and leads to loss of contractile elements and myocyte hypertrophy and has been summed up with the phrase "AF begets AF" (ref. 11).

Figure: vicious cycle of Afib: electrical, contractile, and structural modeling.

Aberrant electrophysiological activity, which is at the basis of these morphological changes, may include focal ectopic triggers as well as both single and multiple circuit reentries, maintaining and eventually leading to progression of Afib.

Pharmacological therapies that do not effectively control Afib may result in atrial remodeling and the sustenance of arrhythmias that are more refractive to treatment (ref. 12).