Possible Molecular Mechanisms by which Angiotensin II Type 1 Receptor Blockers (ARBs) Prevent the Development of Atrial Fibrillation in Insulin Resistant Patients

Atrial fibrillation (AF) is the most common disorder of cardiac rhythm and is responsible for substantial morbidity and mortality in general population. A recent community-based observational study revealed that diabetes and/or hypertension were associated with the development of AF. However, there is no definite evidence to show that patients with type 1 diabetes have an increased risk for the development of AF. These findings suggest that hyperglycemia per se may not explain the positive association between diabetes and AF. Growing body of evidence supports the presence of insulin resistance as the fundamental pathophysiological disturbance responsible for the metabolic syndrome, a constellation of metabolic disorders such as hypertension, dyslipidemia, and obesity that raise the risk for diabetes mellitus and cardiovascular diseases. Further, several clinical trials have shown that the renin-angiotensin system (RAS) plays an important role in the pathogenesis of insulin resistance. These observations suggest that insulin resistance could account for the increased risk for AF in the patients with diabetes and/or hypertension and that the interruption of the RAS may be a promising therapeutic strategy for preventing the development of AF. In the first part of this paper, we review clinical studies to support the concept that angiotensin II type 1 receptor blockers (ARBs) could prevent the development of AF in insulin resistant patients and discuss the possible underlying mechanisms. In the second part, we discuss the potential utility of telmisartan, a unique ARB with peroxisome proliferator-activated receptor-gamma (PPAR-gamma)-modulating activity, for blocking the development of AF in patients with insulin resistance.