IJCS | Volume 32, Nº5, September/October 2019

DOI: 10.5935/2359-4802.20190078 505 EDITORIAL International Journal of Cardiovascular Sciences. 2019;32(5):505-507 Mailing Address: Mohammad Abdelghani Heart Center, Segeberger Kliniken - Am Kurpark 1. Postal Code: 23795, Bad Segeberg - Germany. E-mail: m.abdelghani.nl@gmail.com Conduction Abnormalities after Transcatheter Aortic Valve Replacement: Pretty Common, Fairly Predictable, Barely Avoidable Mohammad Abdelghani 1,2, 3 Heart Center Bad Segeberg, 1 Bad Segeberg - Germany Academic Medical Center, University of Amsterdam, 2 Amsterdam - The Netherlands Al-Azhar University, 3 Cairo - Egypt Editorial related to the article: Incidence of Conduction Disorders and Requirements for Permanent Pacemaker After Transcatheter Aortic Valve Implantation Aortic Valve Stenosis/complications; Aortic Valve Stenosis/physiopathology; Arrhythmias,Cardiac; Bundle-Branch Block/etiology; Transcatheter Aortic Valve Replacement/adverse effects; Pacemaker,Artificial. Keywords The cardiac conduction system is commonly diseased in patients with aortic valve disease, and the site of conduction defect in those with severe calcific aortic valve stenosis is most commonly the His bundle or infra- Hisian. 1,2 The bundle of His traverses the membranous septum towards the left ventricular outflow tract (LVOT) running superficially over the crest of the ventricular septum, originating the left bundle branch. This anatomical course makes the His bundle and its left branch susceptible to mechanical injury during transcatheter aortic valve replacement (TAVR), which involves multiple mechanical manipulations with wires, catheters, balloons, and the transcatheter heart valve (THV) inflow within that vicinity. Atrioventricular and intra-ventricular conduction abnormalities are indeed a common finding in patients with severe aortic valve stenosis referred to TAVR and new onset persistent conduction abnormalities (NOPCAs) are a common complication arising during/after TAVR. Unlike other periprocedural complications of TAVR, whose incidence has decreased over time, a regression in the incidence of NOPCAs after TAVR was neither seen with the introduction of new TAVR technologies/ techniques 3 nor it is foreseeable in the near future. The realization of the prognostic value of NOPCAs and new permanent pacemaker implantation (NPPI) after TAVR went through different phases that correspond to the main phases of TAVR evolution. When TAVR was introduced as a bail out option for extremely morbid patients who – otherwise – have no definitive therapeutic options, NOPCAs/NPPI were seen as an affordable price to pay compared with the extremely high mortality of those patients if managed conservatively. When TAVR then became an option to those who can undergo surgery – albeit at high risk – NOPCAs/NPPI stimulated some scrutiny, but the high risk of surgery led to continued underestimation of the problem. Today, as TAVR is considered an option even in low-risk patients, NOPCAs/NPPI are seen as a clear downside of TAVR as compared to surgery. Accumulating evidence suggests that NOPCAs (especially left bundle branch block — LBBB) and NPPI are still common complications of contemporary TAVR and are associated with impaired left ventricular reverse remodeling and increased heart failure hospitalizations and cardiac death after TAVR. 4,5 In this issue of the International Journal of Cardiovascular Sciences, the study by Santos et al., 6 confirms that NOPCAs and NPPI continue to occur at exceedingly high rates after TAVR, especially with the Medtronic CoreValve. Similar to previous studies that involved relatively small sample size of (very) high risk patients and relatively short follow-up, the authors did not find a significant negative impact of NOPCAs on survival. Beyond incidence and prognostic value, the study explored the predictors of NOPCAs. Identification of the causes/predictors of post-TAVR NOPCAs is of