Regional left atrial conduction velocity in the anterior wall is associated with clinical recurrence of atrial fibrillation after catheter ablation: efficacy in combination with the ipsilateral low voltage area

Abstract

Background: Left atrial (LA) conduction velocity (CV) is an electrical remodeling parameter of atrial fibrillation (AF) substrate. However, the pathophysiological substrate of LA-CV and its impact on outcomes after catheter ablation for AF have not been well evaluated.

Methods: We retrospectively evaluated 119 patients with AF who underwent catheter ablation and electroanatomical mapping during sinus rhythm. To measure regional LA-CV, we took triplet sites (A, B, and C) on the activation map and calculated the magnitude of the matched orthogonal projection vector between vector-AB and vector-AC, indicating two-dimensional CV. The median of the LA-CVs from four triad sites in both the anterior and posterior walls was set as the 'model LA-CV'. We evaluated the impact of the model LA-CV on recurrence after ablation and relationship between the model LA-CV and LA-low voltage area (LVA) of < 0.5 mV.

Results: During the 12-month follow-up, 29 patients experienced recurrence. The LA-CV model was significantly correlated with ipsilateral LVA. The lower anterior model LA-CV was significantly associated with recurrence, with the cut-off value of 0.80 m/s having a sensitivity of 72% and specificity of 67%. Multivariable analysis revealed that the anterior model LA-CV (hazard ratio, 0.09; 95% confidence interval, 0.01-0.94; p = 0.043) and anterior LA-LVA (hazard ratio, 1.06; 95% confidence interval, 1.00-1.11; p = 0.033) were independently associated with AF recurrence. The anterior LA-LVA was mildly correlated with the anterior model LA-CV (r = -0.358; p < 0.001), and patients with both lower LA-CV and greater anterior LA-LVA based on each cut-off value had the worst prognosis. However, decreased LA-CV was more likely to be affected by the distribution pattern of the LVA rather than the total size of the LVA.

Conclusion: Decreased anterior LA-CV was a significant predictor of AF recurrence and was a useful electrical parameter in addition to LA-LVA for estimating AF arrhythmogenicity.

Keywords: Atrial fibrillation; Catheter ablation; LA conduction velocity; Low voltage area; Recurrence.

Fig. 1

Analysis of LA-CV. (A) Local triplet points (A, B, and C) were set to make a triad region for measurement of the LA-CV vector along the direction of wave front propagation with avoidance of visual collision in the activation map. When point A was defined as the earliest point in this triangle, vector-AB and vector-AC were calculated for one-dimensional CV with the activation time and distance between points A and B or C. Then, we incorporated cartesian and trigonometric equations to calculate the magnitude of matched components between the vector-AB and vector-AC as forming the orthogonal projection, which resulted in velocity specifically in the two-dimensional direction of activation. (B) Four matched projection vectors were analyzed at different triad regions of each anterior and posterior LA wall. The medians of the LA-CVs from the four triad sites were set as ‘model LA-CVs’ in both anterior and posterior walls. These regions for analysis must be randomly selected and evenly distributed in the whole anterior and posterior regions and not to be inclined toward one side, respectively. CV, conduction velocity; LA, left atrium

Fig. 2

ROC curves and cut-off points of LA-CV (A) and LA voltage area (B) for associations with AF recurrence after catheter ablation. AF atrial fibrillation; AUC, area under the curve; CV, conduction velocity; LA left atrium; NPV, negative predictive value; PPV, positive predictive value; ROC, receiver operating characteristic

Fig. 3

Kaplan-Meier curves of the survival-free rate of AF recurrence after ablation according to the cut-off point of the anterior model LA-CV of 0.80 m/s. AF, atrial fibrillation; LA-CV, left atrial conduction velocity

Fig. 4

Kaplan-Meier curves of the survival-free rate from AF recurrence in the four groups according to two cut-off points (anterior model LA-CV value of 0.80 m/s and anterior LA-LVA value of 15.5 cm2). AF, atrial fibrillation; LA-CV, left atrial conduction velocity; LA-LVA, left atrial low voltage area

Fig. 5

Kaplan-Meier curves of the survival-free rate of AF recurrence after ablation according to the cut-off point of the anterior model LA-CV of 0.80 m/s in patients with paroxysmal AF and persistent AF. AF, atrial fibrillation; LA-CV, left atrial conduction velocity