The incidence of transcatheter aortic valve implantation-related heart block in self-expandable Medtronic CoreValve and balloon-expandable Edwards valves.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has been performed at Waikato Hospital for high-risk severe symptomatic aortic stenosis patients who are considered unsuitable for conventional cardiac surgery for the last 3 years. The Medtronic CoreValve (MCV) is a self-expandable device, while the Edwards SAPIEN valve (EV) requires the use of a balloon to expand the device. This observational study reports and compares the incidence of heart block in both Medtronic and Edwards transcatheter valves.

METHODS: All patients who underwent TAVI between the periods of 28 August 2008 and 27 July 2011 were included in this study. Preprocedure and daily postprocedure until discharge electrocardiograms (ECG) were obtained prospectively. New onsets of significant atrioventricular (AV) and bundle branch blocks were recorded. Patients with existing pacemaker and those who did not survive the procedure were excluded.

RESULTS: Sixty patients underwent TAVI during the study period, of whom 40 (67%) and 20 (33%) patients had MCV and EV implanted, respectively. Seven patients were excluded from the analysis; 38 MCV and 15 EV patients fulfilled the criteria for analysis. Mean age was 80 ± 7 years, 57% were male. Five patients (9%) required permanent pacemaker (PPM) implantation, which occurred exclusively post MCV TAVI (MCV vs EV: 13% vs 0%, respectively; P=.02). The indications of PPM were complete heart block in 3 patients (60%), Mobitz II second-degree heart block in 1 patient (20%), and symptomatic sick sinus syndrome in 1 patient (20%). The incidence of left bundle branch block (LBBB) was increased after the TAVI procedure and was more significant with MCV implants (MCV vs EV: 42% vs 8%, respectively; P<.01). Of note, 2 of the 5 patients (40%) with pre-existing right bundle branch block (RBBB) who underwent TAVI required PPM (P=.01).

CONCLUSION: MCV implantation is associated with a higher incidence of significant AV block requiring PPM implantation and LBBB compared to EV. The overall rate of PPM requirement post MCV TAVI is, however, lower than previously published data. Pre-existing RBBB may help in predicting the likelihood of developing significant AV block.