Left Atrial Voltage during Sinus Rhythm in Paroxysmal and Persistent Atrial Fibrillation Patients without Structural Heart Disease

Background: The mechanisms underlying self-perpetuation of persistent atrial fibrillation (AF) are not well understood. To gain insight into these mechanisms, we compared biatrial electroanatomic maps, obtained during sinus rhythm, in patients with paroxysmal AF, patients with persistent AF, and patients without AF (control patients). Methods: The study involved 12 patients with paroxysmal AF (9 men, 3 women; 62 ± 11 years of age), 6 patients (5 men, 1 woman; 62 ± 6 years of age) with persistent AF treated unsuccessfully by direct-current cardioversion, and 6 patients (1 man, 5 women; 53 ± 16 years of age) with a left-sided accessory pathway but no AF (control patients). Biatrial voltage mapping was performed during sinus rhythm using the CARTO system. The clinical and electroanatomic characteristics of the 3 groups of patients were evaluated and analyzed statistically. Results: The proportions of normal and low voltage areas in the right and left atria were not different between the control and paroxysmal AF groups. The proportion of the right atrial (RA) low voltage (< 0.5 mV) area did not differ between the 3 groups; however, the RA and left atrial (LA) normal voltage (≥ 1.5 mV) areas were significantly smaller in the persistent AF group. The LA low voltage area was significantly larger in patients with persistent AF. Conclusion: The relatively large RA normal voltage and LA low voltage areas that we observed in patients with persistent AF may play a crucial role in the self-perpetuation of AF.