Ventricular response as a predictor of the termination of sustained paroxysmal atrial fibrillation

Background: Atrial fibrillation (AF) is the most common sustained atrial arrhythmia. Accurate detection of the timing and possibility of AF termination is vital for optimizing rhythm and rate control strategies. The present study evaluated whether the ventricular response (VR) in AF offers a distinctive electrocardiographic indicator for predicting AF termination. Methods: Patients experiencing sustained paroxysmal AF for more than 3 h were observed using 24-h ambulatory Holter monitoring. VR within 5 min before AF termination (VR 0–5 min, BAFT) was compared with VR observed during the 60th to 65th min (VR 60–65 min, BAFT) and the 120th to 125th min (VR 120–125 min, BAFT) before AF termination. Maximum and minimum VRs were calculated on the basis of the average of the highest and lowest VRs across 10 consecutive heartbeats. Results: Data from 37 episodes of paroxysmal AF revealed that the minimum VR0–5 min, BAFT (64 ± 20 bpm) was significantly faster than both the minimum VR120–125 min, BAFT (56 ± 15 bpm) and the minimum VR60–65 min, BAFT (57 ± 16 bpm, p <.05). Similarly, the maximum VR0–5 min, BAFT (158 ± 49 bpm) was significantly faster than the maximum VR120–125 min, BAFT (148 ± 45 bpm, p <.05). In the daytime, the minimum VR0–5 min, BAFT (66 ± 20 bpm) was significantly faster than both the minimum VR60–65 min, BAFT (58 ± 17 bpm) and minimum VR120–125 min, BAFT (57 ± 15 bpm, p <.05). However, the mean and maximum VR0–5 min, BAFT in the daytime were similar to the mean and maximum VR120–125 min in the daytime, respectively. At night, the minimum, mean, and maximum VR0–5 min, BAFT were similar to the minimum, mean, and maximum VR120–125 min, respectively. Conclusions: Elevated VR rates during AF episodes may be predictors for the termination of AF, especially during the daytime and in patients with nondilated left atria. These findings may guide the development of clinical approaches to rhythm control in AF.