Intraprocedural dynamics of cardiac conduction during transcatheter aortic valve implantation: Assessment by simultaneous electrophysiological testing.

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 bears the risk of atrioventricular conduction disorders. The underlying pathophysiology is not fully understood.

Objective: The purpose of this study was to characterize the impact of TAVI on the conduction system as assessed by simultaneous electrophysiological testing.

Methods: AH and HV intervals and QRS duration were measured using a quadripolar His catheter and surface electrocardiogram in 108 patients at baseline (BL), after balloon predilation (timepoint 1 [T1]), after implantation of the valve prosthesis (T2), and after postdilation, if deemed necessary (T3).

Results: Between BL and T2, significant increases of HV interval and QRS duration were observed, with a mean delta of +12.4 ms and +32.7 ms, respectively. Both balloon predilation and valve implantation had an impact on infranodal conduction. No significant increase of AH intervals was documented. The increase of QRS duration led to left bundle branch block (LBBB) in 57 patients (52.8%). Implantation depth positively correlated with QRS prolongation (ρ = 0.21, P = .042) but not with changes of AH or HV interval (ρ = -0.03, P = .762; and ρ = 0.15, P = .130, respectively).

Conclusion: Electrophysiological testing during TAVI shows impairment of infranodal atrioventricular conduction by balloon predilation 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 electrocardiogram.