Background: Transcatheter aortic valve implantation (TAVI) is a less invasive technique for the treatment of severe aortic stenosis in high-risk patients. Occurrence of conduction disturbances requiring permanent pacemaker (PPM) implantation after TAVI is frequently observed.
Methods: The retrospective analysis comprised 153 patients (96 women, aged from 65 to 97 years) who underwent TAVI due to high-grade aortic stenosis. The aim was to evaluate the incidence of high-grade atrioventricular (AV) block after TAVI and the percentage of ventricular pacing and pacemaker (PM)-dependency at the first follow-up 6-8 weeks after implantation.
Results: Out of the 153 patients (age 81 ± 6 years) who underwent TAVI, 144 (94 %) had a transfemoral and 9 (6 %) patients a transapical approach. A PPM was implanted in 31 (20 %) patients, 24 (16 %) were implanted with the Medtronic CoreValve® and 7 (5 %) with the Edwards Sapien® valve (p = n.s.). Complete AV block was the indication in 21 patients (68 %), second-degree AV block in 1 patient (3 %), slow atrial fibrillation in 3 patients (10 %), new left bundle branch block (LBBB) plus sustained ventricular tachycardia (VT) in 1 patient (3 %), sick sinus syndrome in 2 patients (7 %), whereas in 3 patients (10 %) a PPM was inserted for safety reasons because of new LBBB and first-grade AV block. All of the nine patients (6 %) with a preexisting bundle branch block developed total AV block after TAVI. At follow-up PM-dependency (intrinsic rhythm < 30 bpm) occurred in 11/30 patients (37 %), whereas an intrinsic rhythm > 50 bpm was seen in 17 patients (57 %). At nominal device programming the percentage of ventricular stimulation (VP) during the short-term observation period was 60 ± 44 % in dual-chamber devices (N = 18), and 70 ± 36 % in single-chamber PPM (N = 5).
Conclusion: The PPM implantation rate of about 20 % after TAVI is comparable to previously published data. The need for permanent pacing is linked to the valve type and preexistence of a right bundle branch block. At short-term more than half of the patients implanted with a device were not strictly PM-dependent, but presented an underlying intrinsic rhythm, indicating that temporary AV conduction disturbances may recover over time. This might justify a more conservative approach in some patients under watchful waiting. From another point of view, ventricular pacing at a regular or sensor-modulated rate may provide rhythm stability and chronotropy during the short-term period post-TAVI.
Keywords: AV node; Aortic stenosis; Conduction system; Pacemaker; Transcatheter aortic valve implantation.