Abstract 2449: Clinical Significance of Transcardiac Aldosterone Extraction in Patients With Atrial Tachycardia
Background: According to recent evidences, upstream therapy may have the potential to decrease the incidence of atrial tachycardia. However, roles of renin-angiotensin-aldosterone system (RAAS) in atrial arrhythmia patients are still unclear. The measurement of blood indices form the peripheral circulation may not reflect intracardiac environment. We therefore measured the level of aldosterone as a final mediator of RAAS at the aortic root (AO) and coronary sinus (CS) to evaluate the transcardiac gradient of aldosterone level in the atrial tachycardia cases.
Methods: Seventy consecutive patients with atrial tachycardia including atrial flutter, paroxysmal atrial fibrillation and long standing atrial fibrillation patients (group A) and 75 consecutive patients without atrial tachycardia (group N) were studied. Sampling of blood for measurement of aldosterone levels was performed at the AO and CS. We compared the mean aldosterone level at AO between two groups and assessed the transcardiac gradient of those levels in both groups.
Results: The mean of aldosterone at AO of group A was higher than the aldosterone at AO of group N (68.0 pg/ml in group A, 40.8 pg/ml in group N; p=0.0043). The mean of aldosterone at CS decreased compared to aldosterone at AO in group A (53.4 pg/ml at CS, 68.0 pg/ml at AO; p=0.0007). On the other hand, there was no remarkable transcardiac stepdown of aldosterone level in group N(40.8 pg/ml at CS, 41.1 pg/ml at AO; n.s.). Among the subgroups of atrial flutter, paroxysmal atrial fibrillation and long standing atrial fibrillation patients transcardiac reduction of aldosternoe was greatest in the long standing atrial fibrillation subjects and smallest in the atrial flutter subjects (−7.2 pg/ml in group atrial flutter group, −14.3 pg/ml in paroxysmal atrial fibrillation group, −30.8 pg/ml in long standing atrial fibrillation group; p=0.0123).
Conclusions: These findings demonstrated elevated aldosterone at AO and transcardiac extraction of aldosterone in atrial tachycardia cases. These findings are reinforced by stepwise transcardiac gradient with higher atrial fibrillation burden. RAAS blocking approach is supposed to have the potential to decrease the incidence of atrial tachycardia.