Key result
Dynamic ECG features, specifically an average number of long RR intervals > 3.0 s and escape rhythm episodes < 35 bpm, were significant predictive factors of second-degree AVB after ablation.
Why the study?
Can dynamic electrocardiography predict underlying second-degree atrioventricular block in patients with persistent atrial fibrillation and long RR intervals?
Cohort (n=204)
Can dynamic electrocardiography predict underlying second-degree atrioventricular block in patients with persistent atrial fibrillation and long RR intervals?
p-value: p=< 0.05
Dynamic ECG parameters, specifically long RR intervals > 3.0 s and escape rhythm episodes < 35 bpm, can help predict the presence of underlying second-degree AV block in patients with persistent AF undergoing ablation.
May aid DCG detection of occult AVB in persistent AF; hypothesis-generating and requires prospective validation before practice change.
BACKGROUND: Periodic electrocardiography (ECG) at every clinical visit is generally performed for heart rhythm surveillance, and 24-h Holter ECG is usually used as the gold standard. We aimed to investigate the electrocardiographic features of persistent atrial fibrillation (AF) accompanied with second-degree atrioventricular block (AVB). METHODS: From October 2012 to November 2015, 204 patients with an RR interval > 2.0 s before radiofrequency ablation were included. Dynamic ECG (DCG) was performed before and after the radiofrequency ablation. The patients were divided into two groups based on changes in DCG after radiofrequency ablation: group A (non-second-degree AVB group) and group B (second-degree AVB group). An RR interval > 2.0 s, the distribution of escape rhythm, mean heart rate and the long RR interval in the two groups were analyzed. RESULTS: After radiofrequency ablation, all 204 patients who had persistent AF converted to sinus rhythm successfully. In group A (n = 193), the distribution of an RR interval > 2.0 s and escape rhythm were significantly correlated with sleep or rest, while no correlation was observed in group B (n = 11). The average RR interval prolongation and escape rhythm were significantly higher in group B than in group A (p < 0.05). The average number of long RR intervals > 3.0 s and average number of escape rhythm episodes (< 35 bpm) were significant predictive factors of second-degree AVB after radiofrequency ablation. CONCLUSIONS: DCG is a useful tool for the diagnosis of persistent AF accompanied with second-degree AVB.
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Zhang et al. (2018) conducted a cohort in Persistent atrial fibrillation accompanied with second-degree atrioventricular block (n=204). Dynamic ECG (DCG) features (long RR intervals > 3.0 s and escape rhythm < 35 bpm) vs. Absence of these features was evaluated on Second-degree AVB after radiofrequency ablation (p=< 0.05). Dynamic ECG features, specifically an average number of long RR intervals > 3.0 s and escape rhythm episodes < 35 bpm, were significant predictive factors of second-degree AVB after ablation.
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