Some Post-TAVR Arrhythmias Likely Present
Pre-TAVR but Go Undetected

Is Prolonged ECG Testing Needed Pre-TAVR?

Debra L. Beck

July 20, 2020

In a prospective study of 106 patients undergoing transcatheter aortic valve replacement (TAVR) for severe aortic stenosis, 48.1% were found to have preexisting arrhythmias on prolonged ECG monitoring.

With 1 week of continuous monitoring, new atrial fibrillation (AF) was detected in 7.6% of patients, atrial tachycardia in 2.5%, nonsustained ventricular arrhythmias in 29.2%, and significant bradyarrhythmias in 20.8%. Early diagnosis of arrhythmias led to treatment changes in 27.5% of patients.

Post-TAVR telemetry showed "new-onset" arrhythmic events in 22.1% of patients, of which one third had been identified as having an arrhythmia on the prolonged ECG screening.

"When we see an arrhythmia on telemetry after TAVR, we assume the procedure is responsible for it — and this is the case in a lot of patients — but there are many that seem to have some kind of a substrate or a predisposition going into the procedure, and we won't detect it unless we do prolonged ECG monitoring," said senior author Josep Rodés-Cabau, MD, from the Quebec Heart and Lung Institute, Laval University, Quebec City, Canada.

Rodés-Cabau and colleagues, including first author Lluis Asmarats, MD, also from Quebec Heart and Lung Institute, published their findings July 15  in  JACC: Cardiovascular Interventions.

Not all of the arrhythmias they found require intervention, Rodés-Cabau noted in an interview with theheart.org | Medscape Cardiology, but just the knowledge of their existence can be clinically important.

"Let's say a sinus node dysfunction after TAVR turns into a severe bradyarrhythmia. Even in the absence of beta-blockers or any drug that can induce bradyarrhythmia, that 88-year-old patient might have had that slow heart rate for a long time and not been symptomatic enough to require a pacemaker, but now you have documented a potential indication for one after the TAVR. Since the implant occurred after the TAVR, you would count that event as a complication post-TAVR but really it is not related to the procedure," he said.  

He suspects that as more, younger individuals undergo TAVR as indications loosen, the arrhythmic complication rates will go down.

"I am quite sure that when we will be treating younger patients, all of this arrhythmic burden will decrease, but nowadays we're still treating these intermediate- to high-risk patients and the preexisting arrhythmic burden in this group is very high," said Rodés-Cabau.

Some of the arrhythmias seen pre-TAVR appear to foretell post-TAVR events. Among those patients with preexisting first-degree atrioventricular block or right bundle branch block, and concomitant severe bradyarrhythmias seen pre-TAVR, 66.7% and 50%, respectively, went on to require a permanent pacemaker either before or after TAVR.

The PARE (Prolonged Continuous ECG Monitoring Prior to Transcatheter Aortic Valve Implantation) study prospectively enrolled 106 patients (mean age, 80 years) with severe aortic stenosis and no prior permanent pacemaker.  Within 3 months of planned TAVR, participants underwent a 7-day ECG screening (CardioSTAT, Icentia; Quebec City, Canada).

All therapeutic measures taken in response to ECG monitoring were recorded and all patients were monitored by telemetry post-TAVR until hospital discharge.

In all, 90 patients underwent elective TAVR following heart team evaluation. More than half (58%) were done with the Sapien 3 valve (Edwards Lifesciences; Irvine, California), which has been linked to higher PPM rates, and, thus, may have influenced the study's PPM rates, the authors noted.

If You Look, You Will Find

In an accompanying editorial, Stefan Toggweiler and Richard Kobza, both from the Heart Center Lucerne, Switzerland, said the prevalence of AF detected on 7-day monitoring in this study exactly matches the 7% to 8% incidence of new-onset AF post-TAVR reported previously, suggesting "that many, if not the majority, of patients with so-called new-onset AF may actually have preexisting, but undetected, AF."

The findings on bundle branch block are also intriguing, they said, noting that the presence of right bundle branch block pre-TAVR appeared to be not only a risk factor for a permanent pacemaker after TAVR, but also a sign of "a generally more vulnerable conduction system, with an increased incidence of bradyarrhythmias before TAVR."

Given the already heavy burden of pre-TAVR planning, one that often requires a dedicated coordinator just to shepherd patients through, they suggest that a reasonable strategy might be to perform 7-day ECG screening in patients with preexisting conduction disorders and borderline indications for a permanent pacemaker.

Screening can also be considered for those with severe chronic kidney disease, heavily calcified valves, and reduced left ventricular function, they added.

A randomized trial would help clinicians better understand whether pre-TAVR continuous ECG screening improves outcomes, said the editorial writers. Their guess is that adoption of this strategy might best serve to reduce length of stay and "streamline" post-TAVR care in higher-risk patients because their conduction abnormalities will be detected and managed before the procedure.

Agreeing with this idea, Rodés-Cabau said a trial would be "ideal," but the outcomes would have to be carefully selected. "If you look, for example, to decrease the incidence of stroke, you will need thousands and thousands of patients to demonstrate that. I think it would be more realistic to look at changes in logistics or peri-procedural care with pre-procedural 7-day ECG screening," he said.

Rodés-Cabau holds the research chair "Fondation Famille Jacques Larivière" for the Development of Structural Heart Disease Interventions, and has received research institutional grants from Medtronic, Edwards Lifesciences, and Boston Scientific. Toggweiler is a consultant and proctor for Boston Scientific, New Valve Technology, and Abbott Vascular; has received institutional research grants from Boston Scientific and Federica; and holds equity in Hi-D Imaging. Kobza has received institutional research grants from Abbott Vascular, Biosense-Webster, Biotronik, Boston Scientific, Medtronic, and SIS Medical.

JACC Cardiovasc Interv. Published online July 15, 2020. Article

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