This is a prospective single center Cardiology department observational study. The study aim is to better understand the predictors of high grade conduction abnormalities associated with TAVR such that a more robust evidence-based and universal strategy to manage cardiac conduction disturbances in these patients, which has been elusive, can be developed.

TAVR is a very commonly performed procedure throughout the world; it has become standard of care as the treatment for aortic stenosis and is performed in hundreds of thousands of patients annually. TAVR affords patients therapies that prolong life and improve quality of life; furthermore, these therapies afford certain patients who are not candidates for surgical options hope for the future. Adults undergoing TAVR may suffer the complication of requiring a pacemaker after the procedure, in up to 30% of cases. Interventionalists still don't understand how to best predict this complication; in fact some patients that ultimately need a pacemaker don't get one after the procedure and some that get a pacemaker are found to ultimately not have really needed it. A better understanding of which patients do and do not need pacemakers will help prevent complications of high grade block in those without pacemaker (death, syncope and trauma) and also the complications of unnecessary pacemaker implantation (infection, tricuspid regurgitation).

Primary hypothesis: EP studies (EPS), when performed before and after TAVR adds independent incremental value, above and beyond other parameters, for the prediction of high-grade heart block after TAVR. The goal is to understand conduction disease changes before and after TAVR, coupled with other patient and procedural factors that can help create a management algorithm for conduction disease after TAVR.

Primary endpoint: to find correlation coefficients between a) absolute and delta values of various EPS findings, and b) clinical endpoint of high-grade conduction disease as diagnosed clinically, by ECG, by event monitor, or by interrogation of permanent pacemaker implanted after TAVR.

Methods: Patients will receive EPS immediately before and after TAVR (while on the catheterization lab table for TAVR procedure) and then again the next day; this information will help determine whether the patient gets a pacemaker, a 30-day event monitor, or neither. The investigators will study which parameters obtained during the EPS, in addition to other known/suspected predictors of conduction disease after TAVR, best correlate with serious problems with the heart's electrical conduction system as determined by clinical follow-up.

Anticipated findings: that the EPS findings add incremental and independent value in predicting which patients will develop high grade conduction disease.

Inclusion Criteria

• Signed and dated Informed Consent
• Patient that undergoes a TAVR
• Ability to complete functional assessments.

Exclusion Criteria:

• Patients with pre-existing permanent pacemaker.
• Patient unwilling or unable to follow-up for necessary pre- and post-procedure clinical assessments.