Introduction and objectivesLittle is known about the timing of onset and outcome of conduction abnormalities (CA) following balloon-expandable transcatheter aortic valve implantation. The aim of this study was to examine the timing of CA and determine the impact of balloon aortic valvuloplasty (BAV) on the persistence of these abnormalities. MethodsA total of 347 patients were included. Of these, 75 had a continuous electrocardiogram recording and a 6-lead electrocardiogram at each step of the procedure. ResultsIn the transcatheter aortic valve implantation population undergoing continuous electrocardiogram monitoring, new-onset left bundle branch block (LBBB) or third-degree atrioventricular block occurred in 48 (64%) and 16 (21.3%) patients, with 51.5% of CA occurring before valve implantation. Left bundle branch block persisted more frequently at hospital discharge (53.8 vs 22.7%; P=.028) and at 1-month follow-up (38.5 vs 13.6%; P=.054) when occurring before valve implantation. Balloon aortic valvuloplasty prior to valve implantation was used in 264 (76.1%) patients, and 78 (22.5%) had persistent LBBB or complete atrioventricular block requiring pacemaker implantation. Persistent LBBB or unresolved atrioventricular block at 1 month occurred more frequently in the BAV group (76.1 vs 47.6%; P=.021), and the use of BAV was associated with a lack of CA resolution (OR, 3.5; 95%CI, 1.17-10.43; P=.021). ConclusionsIn patients undergoing a balloon-expandable transcatheter aortic valve implantation, more than half of CA occurred before valve implantation. Early occurrence of CA was associated with a higher rate of persistence at 1-month follow-up. The use of BAV was associated with an increased risk of CA persistence.Full English text available from:www.revespcardiol.org/enFull English text available from:www.revespcardiol.org/en