Atrial synchronization during bachmann bundle Pacing can be non-Invasively evaluated using lead V8
S Mulier, A Fennema, V Ramalingam, J van Koll, M Mafi-Rad, J Luermans, D Linz, J Joza, K VernooyAbstract
Background
Bachmann bundle pacing (BBP) is an atrial pacing strategy that targets the dominant interatrial conduction pathway to synchronize interatrial conduction by advancing left atrial (LA) activation. However, the degree of interatrial synchronization remains difficult to quantify, and activation criteria are lacking. Identifying LA activation on the surface electrocardiogram would be of great importance to enable evaluation of the effect of BBP. Surface lead V8 has previously been shown to correlate with the latest activation of the left ventricle during cardiac resynchronization therapy.
Purpose
To evaluate whether the negative derivative activation time (NDAT) of the P wave in surface lead V8 corresponds with the latest LA activation time.
Methods
Consecutive patients undergoing catheter ablation at two tertiary centres (the Netherlands and Canada) were enrolled. All patients required the presence of a decapolar diagnostic catheter positioned in the coronary sinus. The 12-lead ECG was recorded with surface lead V5 positioned at the V8 location (2cm below the point of the left scapula). Temporary pacing was performed at the Bachmann pacing region and at alternative right atrial sites (RAP), including right atrial appendage and superior vena cava, using a diagnostic, ablation, or mapping catheter. The latest activation on the coronary sinus catheter was recorded and timed with the surface p wave in lead V8 (figure 1A). Linear regression and Bland-Altman analysis was performed.
Results
A total of 50 patients were included; the majority undergoing catheter ablation for atrial fibrillation. Mean age 64±10 years, left ventricular ejection fraction 53±9%, and left atrial volume index 40±12 mL/m². During stimulation at the Bachmann area, the mean P-wave duration was significantly shorter compared with baseline sinus rhythm (107± 21ms vs. 150±25ms, p<0.001) and RAP (135±26ms, p<0.001). P-wave NDAT-V8 was shortest during stimulation at Bachman area (90±22ms), compared with sinus rhythm (129±25ms, p < 0.001) and RAP (112±27; p < 0.001). P-wave NDAT-V8 showed a strong correlation with the latest CS activation during sinus rhythm and with pacing at any region (r=0.96, p<0.001, figure 1B). Bland–Altman revealed a mean bias of 0.9ms with 95% limits of agreement from -19.2 to 20.9ms.
Conclusion
The P-wave NDAT determined in surface lead V8 closely reflects the invasively derived latest LA activation time at the sinus coronarius and serves as a reliable non-invasive surrogate. Accordingly, P-wave NDAT-V8 may be used during BBP to assess the degree of interatrial synchronization.Correlation NDAT and CS activation