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Given today's short hospital stays after transcatheter aortic valve replacement (TAVR), there may be a role for selective long-term monitoring to flag delayed conduction abnormalities, studies showed.

Researchers tested two continuous ECG monitoring approaches post-TAVR -- one using skin patches over 14 days, the other implantable loop recorders (ILRs) over 1 year -- in separate studies published in JACC: Cardiovascular Interventions.

Both reports showed that delayed high-degree atrioventricular (AV) block typically occurred within about a week after the procedure, though it did show up months later in some cases according to year-long surveillance.

"At the present time, selective short-term monitoring will likely continue to be the dominant strategy to address delayed HAVB [high-degree AV block] or CHB [complete heart block] after TAVR," wrote Mohamad Alkhouli, MD, of Mayo Clinic School of Medicine in Rochester, Minnesota, in response to the two studies.

"However, futuristic innovations in smart devices, mini-sensors, and removable or dissolvable pacemakers are expected to move the field toward a 'long-term monitoring for all, prophylactic pacemaker implantation for some' strategy to address the growing concerns about delayed and very delayed conduction disturbances after the procedure," Alkhouli wrote in an .

Short-Term Monitoring by ECG Skin Patch

The showed a 4.6% incidence of delayed high-degree AV block or complete heart block after minimalist TAVR in 459 consecutive patients.

With the Zio AT or the CardioSTAT patch worn for 14 days, the ECG episodes were detected at a median 5 days post-TAVR and led to permanent pacemaker (PPM) implant in four out of five affected people, according to Josep Rodés-Cabau, MD, PhD, of Quebec Heart and Lung Institute and Laval University, and colleagues.

By baseline and periprocedural ECG characteristics, some patients appeared more likely than others to develop delayed conduction disturbances after TAVR:

• No right bundle branch block (RBBB) and no ECG changes after TAVR (n=315): 2.2%

• Baseline RBBB and no further changes (n=38): 13.2%

• New-onset ECG conduction disturbances after TAVR (n=106): 8.5%

Based on these findings, the latter two groups in particular may benefit from ambulatory ECG monitoring, especially in the first week after discharge, or a longer hospital stay, Rodés-Cabau's team suggested.

"However, this was a nonrandomized study, and it remains unknown whether ambulatory ECG monitoring could have prevented subsequent life-threatening episodes, including severe episodes of syncope or sudden cardiac death, in those patients with silent arrhythmias who received PPMs on the basis of ambulatory ECG findings," the researchers acknowledged.

"Future large-scale prospective studies with standardized postprocedural management are needed to validate this strategy," the team said.

In 2019, Rodés-Cabau was part of a consensus panel that proposed a on the basis of baseline and post-TAVR ECG.

The current prospective study comprised 459 consecutive TAVR patients without baseline PPMs (mean age 79, 45.3% women).

Most received a balloon-expandable device, with just 14.2% getting a self-expandable valve when undergoing the procedure at one of two centers.

There were no deaths at 30-day follow-up.

Long-Term Monitoring by Implantable Loop Recorder

ILRs revealed a 11.9% incidence of delayed total AV block occurring more than 2 days after TAVR in .

These disturbances were flagged in seven out of 59 people undergoing 12 months of continuous ECG monitoring after TAVR, typically occurring between 2 days and 3 months. In five out of those seven individuals, total AV block was diagnosed only by the ILR and not on a follow-up ECG, reported researchers led by Christian Reiter, MD, of Kepler University Hospital in Linz, Austria.

Predictors of delayed total AV block turned out to be prolongation of the PQ interval from baseline to day 2 (OR 1.04, 95% CI 1.01-1.09) and prolongation of the HV interval during TAVR (OR 1.07, 95% CI 1.02-1.14).

Study participants with RBBB and left bundle branch block were too few for investigators to probe their potential for predicting delayed total AV block [DT-AVB].

"Our findings suggest that personnel taking care of TAVR patients should screen and be alert for bradyarrhythmia and its associated signs and symptoms," the group concluded.

"The regular use of ambulatory monitoring devices such as wearable ECG patch monitors, preferably linked to telemetric systems, should be considered for up to 14 days after TAVR. These devices could play an important role in the detection of DT-AVB, especially in patients with risk factors for its occurrence," the study authors said.

Their single-center study included 59 consecutive TAVR patients without persistent or recurrent total AV block within 48 hours (mean age 80, 39% men). All had received self-expandable TAVR valves.

Loss of ILR interrogation follow-up occurred in 10% of the cohort: three patients after 3 months and another three after 6 months. All six individuals were still alive and had no PPM implantation 12 months after TAVR, Reiter and colleagues reported.