KIELCE, POLAND. In the 2nd virtual LAF Conference in January 2003, the role of aldosterone in the initiation of AF episodes was discussed in considerable detail.[1,2] This was followed by an article in the March 2004 issue of The AFIB Report further elucidating the role of aldosterone in lone atrial fibrillation (LAF). Dr. Patrick Chambers also discussed the role of aldosterone in his article "P Cells and Potassium" published in the March 2005 issue of The AFIB Report. It is likely that aldosterone exerts its negative effects through one or more of the following mechanisms:

• Inflammation and fibrosis (tissue scarring and thickening);
• Increased tendency to blood clotting;
• Impaired fibrinolysis (impaired blood clot digestion and removal);
• Sodium retention;
• Potassium and magnesium loss;
• Disturbance of ANS balance;
• Increased activity of catecholamines (norepinephrine and epinephrine);
• Decreased heart rate variability;
• Increased production of reactive oxygen species (ROS), especially superoxide;
• Decreased production of nitric oxide (NO) and accompanying endothelial dysfunction.

Now a group of Polish researchers report that a decrease in aldosterone level is associated with the maintenance of normal sinus rhythm (NSR) following a successful cardioversion. Their clinical trial involved 45 patients with persistent non-valvular AF and normal left ventricular ejection fraction and 20 matched control subjects with no evidence of AF. The average age of the patients was 59 years and 81% were men. Twenty percent of the group had LAF. The 45 patients were scheduled for electrical cardioversion (CV) after having been in persistent afib for an average of 12 weeks. Plasma aldosterone levels were measured 24 hours prior to CV and again 24 hours after. The baseline aldosterone level was 152 pg/mL in the afib group and 130 pg/mL in the control group (p=0.11).

Forty-three of the initial 45 patients left the hospital in NSR and were examined again 30 days later. At this examination 24 patients (56%) were still enjoying sinus rhythm, while the remaining 19 (44%) had reverted to persistent AF. The Polish researchers noted that while there was no significant difference in aldosterone levels 24 hours prior to CV and 24 hours after in the group that reverted to AF (126 pg/mL vs. 118 pg/mL), there was a sharp decrease from 176 pg/mL to 101 pg/mL in the group that maintained NSR 30 days after CV (p=0.003).

They conclude that a rapid drop of more than 13 pg/mL following CV predicts sinus rhythm maintenance with 87% sensitivity and 64% specificity. They speculate that a largely unchanged aldosterone level after cardioversion may reflect more advanced disease of the atria with enhanced expression of angiotensin converting enzyme (ACE) and local activation of aldosterone excretion. They found no correlation between baseline aldosterone levels and sinus rhythm maintenance 30 days following cardioversion.
[1] Session 2
[2] The AFIB Report, No. 27, March 2003, p. 5

Wozakowska-Kaplon, B, et al. A decrease in serum aldosterone level is associated with maintenance of sinus rhythm after successful cardioversion of atrial fibrillation. PACE, January 4, 2010 [Epub ahead of print]

Editor's comment: This study further emphasizes the crucial role of aldosterone in the genesis of atrial fibrillation and supports the evidence that ACE inhibitors, angiotensin receptor blockers (ARBs), or aldosterone antagonists may increase the chance of maintaining NSR following a cardioversion. See The AFIB Report, March 2004 for further information.