Predictors of high-degree conduction disturbances and pacemaker implantation after transcatheter aortic valve replacement: Prognostic role of the electrophysiological study.

BACKGROUND: Predictors of high-degree atrioventricular block (HAVB) after transcatheter aortic valve replacement (TAVR) are recognized, but the electrophysiological study's (EPS) role is still a subject to debate. The objective of our study was to determine factors associated with PPM implantation including the potential role of EPS before and/or after TAVR. METHODS AND RESULTS: Seventy four consecutive patients (pts) were included and 21 pts (28.4%) received a PPM during the immediate postoperative follow-ups (until Day 5): HAVB in 15 pts (71.4%), prophylactic implantation due to a documented increased HV interval ≥ 95-100 ms plus LBBB in 2 pts (9.5%), a high-degree HV block evidenced at the EPS plus LBBB in 3 pts (14.3%) and one additional patient was implanted for AV-block in presence of AFib (4.8%). In the multivariate model 1 including parameters before TAVR, both prosthesis diameter and PR lengthening remained significantly associated with PPM as well RBBB. In the multivariate model 2 including parameters after TAVR, only HV remained significantly associated with the risk of PPM (OR = 1.15 (1.05-1.26), p = .004). When all the significant variables in models 1 and 2 were analyzed together in model 3, only HV after TAVR remained significantly associated with an increased risk of PPM. CONCLUSIONS: In this prospective observational study, it was revealed that a Day 4-5 EPS is likely to more precisely stratify the risk of PPM implantation regarding its ability to discover asymptomatic severe infra-hisian conduction disturbances particularly in presence of LBBB. Multivariate analysis confirmed the prognostic value of HV alteration.

Evaluation of a real-time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia substrate assessment.

AIMS: Potential advantages of real-time magnetic resonance imaging (MRI)-guided electrophysiology (MR-EP) include contemporaneous three-dimensional substrate assessment at the time of intervention, improved procedural guidance, and ablation lesion assessment. We evaluated a novel real-time MR-EP system to perform endocardial voltage mapping and assessment of delayed conduction in a porcine ischaemia-reperfusion model. METHODS AND RESULTS: Sites of low voltage and slow conduction identified using the system were registered and compared to regions of late gadolinium enhancement (LGE) on MRI. The Sorensen-Dice similarity coefficient (DSC) between LGE scar maps and voltage maps was computed on a nodal basis. A total of 445 electrograms were recorded in sinus rhythm (range: 30-186) using the MR-EP system including 138 electrograms from LGE regions. Pacing captured at 103 sites; 47 (45.6%) sites had a stimulus-to-QRS (S-QRS) delay of ≥40 ms. Using conventional (0.5-1.5 mV) bipolar voltage thresholds, the sensitivity and specificity of voltage mapping using the MR-EP system to identify MR-derived LGE was 57% and 96%, respectively. Voltage mapping had a better predictive ability in detecting LGE compared to S-QRS measurements using this system (area under curve: 0.907 vs. 0.840). Using an electrical threshold of 1.5 mV to define abnormal myocardium, the total DSC, scar DSC, and normal myocardium DSC between voltage maps and LGE scar maps was 79.0 ± 6.0%, 35.0 ± 10.1%, and 90.4 ± 8.6%, respectively. CONCLUSION: Low-voltage zones and regions of delayed conduction determined using a real-time MR-EP system are moderately associated with LGE areas identified on MRI.