Abstract 14807: Atrioventricular Conduction Intervals Before and After Transcatheter Aortic Valve Implantation
The percutaneous implantation of a CoreValve prosthesis in high risk patients (pts) with severe aortic stenosis may induce or worsen atrivoventricular (AV) conduction disturbances. However, there is poor information on AV conduction as assessed by intracardiac electrograms. The aim of the study was to assess the intracavitary intervals before and after percutaneous aortic valve implantation (PAVI).
Methods: From a total of 110 pts with severe aortic stenosis treated withpercutaneous Corevalve implantation, we selected for analysis the last 37 consecutive procedures, where we obtained baseline and 30 minutes post implantation studies of surface electrocardiogram (ECG) combined with measurements of intracavitary intervals.
Results: The mean age was 77±8 years; 26 were female (70%). Based on the baseline surface ECG, 31 had sinus rythm and 6 had atrial fibrillation. The PR interval was prolongued (>200 msec) in 6,out of 31 pts (20%). Thirty-three pts had a normal QRS duration, one had left bundle branch block (LBBB) and 3 had right bundle branch block (RBBB). Regarding baseline intracavitary electrograms, all 37 pts had a normal AH interval (<120 msec). Similarly, the HV interval was less than 70 msec in all 37 pts. Thirty minutes after valve implantation, 4 pts (11%) had develop complete AV block. In none of them the His electrogram could be recorded after treatment. In the remaining 33 pts, the PR interval (162±37 vs 188±50 msec; p<0.05) and the QRS duration (93±18 vs 127± 25 msec; p<0.001) increased significantly; 22 pts developed new LBBB and one a new RBBB. The AH interval (89 ± 29 vs 103 ± 34 msec; p<0.005) and the HV interval (52±10 vs 63±22 msec; p<0.005) also increased significantly.
Conclusions: The stent expansión of the valve at the outflow tract provokes direct damage of the His bundle that slows intraventricular conduction. In addition, the implant may potentially impair the AV nodal conduction, despite the more distant position of the AV-node structures. In pts who developed complete AV block, the His electrogram seems to disappear which may suggests major injury or ablation-type damage of the His bundle.
- © 2011 by American Heart Association, Inc.