Intraprocedural dynamics of cardiac conduction during transcatheter aortic valve implantation - assessment by simultaneous electrophysiology testing

ABSTRACT Background Transcatheter aortic valve implantation (TAVI) is an established treatment for patients with severe aortic stenosis and high to intermediate surgical risk. However, the proximity of the conduction system to the prosthesis landing zone bares the risk of atrioventricular conduction disorders. The underlying pathophysiology is not yet fully understood. Objective The aim of our prospective study was to characterize the impact of TAVI on the conduction system as assessed by simultaneous electrophysiology testing. Methods AH-, HV-intervals and QRS-duration were measured with a quadripolar His-catheter and surface ECG in 108 patients at baseline (BL), after balloon pre-dilatation (timepoint 1, T1), after implantation of the valve prosthesis (T2) and after post-dilatation, if deemed necessary (T3). Results Between BL and T2, a significant increase of HV-interval and QRS-duration was observed with a mean delta of +12.4ms and +32.7ms, respectively. Both, balloon pre-dilatation and valve implantation had an impact on infranodal conduction. No significant increase of AH-intervals was documented. The increase of QRS-duration led to a left bundle branch block (LBBB) in 57 patients (52.8%). Implantation depth positively correlated with QRS-prolongation (ρ = 0.21, p = 0.042) but not with changes of AH- or HV-intervals, respectively (ρ = -0.03, p = 0.762; ρ = 0.15, p =0.130). Conclusions Electrophysiology testing during TAVI shows impairment of the infranodal atrioventricular conduction by balloon pre-dilatation and valve implantation. This impairment is positively correlated with valve implantation depth and results in an increase of QRS-duration with mainly LBBB-pattern on surface ECG.