Intraprocedural dynamics of cardiac conduction during transcatheter aortic valve implantation: Assessment by simultaneous electrophysiological testing

The QRS frontal plane axis changes during left bundle branch block after transcatheter aortic valve replacement

BACKGROUND AND AIMS

Left bundle branch block (LBBB) is common after transcatheter aortic valve replacement (TAVR) and associated with a left or normal QRS axis. We aim to assess the QRS frontal plane axis shift changes during LBBB after TAVR and determine if the risk of procedure-related high degree atrioventricular block (AVB) is affected by QRS axis shift changes.

METHODS AND RESULTS

In a retrospective single-center study of 720 consecutive patients who underwent TAVR, 141 (19.6%) with normal baseline QRS duration developed a new LBBB after TAVR and constituted the study group. Most patients (59.6%) were females and the mean age of the cohort was 81.2 ± 6 years.

RESULTS

As compared with the baseline QRS axis before TAVR, the occurrence of LBBB was associated with a leftward QRS axis shift (by 40 ± 28.3°) in 73% of the study patients and a rightward (by 18.6 ± 19.4°) or no change in QRS axis in 25.6% and 1.4% of the study patients, respectively. A left QRS axis (-30°) was observed in 14.9% and 38.3% of the study patients before and after TAVR, respectively. The group of patients exhibiting a rightward or no QRS axis shift had a greater incidence of high degree AVB than the group of patients exhibiting a leftward QRS axis shift (18.4% vs. 6.8%, p = .056).

CONCLUSION

Although post TAVR-LBBB is associated with a leftward QRS axis shift in most patients, a non-negligible proportion of patients (27%) exhibited a rightward or no QRS axis shift. The latter group tend to have a higher risk of developing high degree AVB.

The R-wave amplitude in V1 on baseline electrocardiogram correlates with the occurrence of high-degree atrioventricular block following left bundle branch block after transcatheter aortic valve replacement

AIMS

Several procedural and electrocardiogram (ECG) parameters have been associated with the occurrence of high-degree atrioventricular block (AVB) requiring permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR). We hereunder sought to assess if the baseline R-wave amplitude in V1 ECG lead of patients with normal QRS duration undergoing TAVR is associated with a higher patient's risk for developing high-degree AVB following left bundle branch block (LBBB).

METHODS AND RESULTS

In this retrospective single-centre study in 720 consecutive patients who underwent TAVR, 141 (19.6%) patients with normal QRS duration developed a new LBBB after TAVR. The 24 (17%) patients who underwent PPI for reasons other than high-degree AVB were excluded from further analysis. In the remaining 117 study patients, 14 (12%) developed high-degree AVB requiring PPI (Group 1) while the remaining 103 (88%) patients did not (Group 2). There were no significant differences in baseline demographic or procedural characteristics nor in PR interval, QRS duration, and QRS axis between these two groups. The incidence of left anterior hemiblock was higher in Group 1 (3 of 14, 21.4%) than that in Group 2 (9 of 103, 8.7%), but the difference was not statistically significant (P = 0.156). The R-wave amplitude in V1 was smaller in Group 1 than that in Group 2 (0.029 ± 0.04 mV vs. 0.11 ± 0.14 mV, P = 0.0316). In the receiver-operating characteristics analysis, the cutoff for R-wave amplitude pre-TAVR was 0.03 mV, area under the curve = 0.7219 (P = 0.0002).

CONCLUSION

The R-wave amplitude in lead V1 during baseline ECG in patients with normal QRS duration may predict the occurrence of high-degree AVB following new LBBB after TAVR.

Invasive electrophysiological testing to predict and guide permanent pacemaker implantation after transcatheter aortic valve implantation: A meta-analysis

Background

Atrioventricular conduction abnormalities after transcatheter aortic valve implantation (TAVI) are common. The value of electrophysiological study (EPS) for risk stratification of high-grade atrioventricular block (HG-AVB) and guidance of permanent pacemaker (PPM) implantation is poorly defined.

Objective

The purpose of this study was to identify EPS parameters associated with HG-AVB and determine the value of EPS-guided PPM implantation after TAVI.

Methods

We performed a systematic review and meta-analysis of studies investigating the value of EPS parameters for risk stratification of TAVI-related HG-AVB and for guidance of PPM implantation among patients with equivocal PPM indications after TAVI.

Results

Eighteen studies (1230 patients) were eligible. In 7 studies, EPS was performed only after TAVI, whereas in 11 studies EPS was performed both before and after TAVI. Overall PPM implantation rate for HG-AVB was 16%. AV conduction intervals prolonged after TAVI, with the AH and HV intervals showing the largest magnitude of changes. Pre-TAVI HV >70 ms and the absolute value of the post-TAVI HV interval were associated with subsequent HG-AVB and PPM implantation with odds ratios of 2.53 (95% confidence interval [CI] 1.11-5.81; P = .04) and 1.10 (95% CI 1.03-1.17; P = .02; per 1-ms increase), respectively. In 10 studies, PPM was also implanted due to abnormal EPS findings in patients with equivocal PPM indications post-TAVI (typically new left bundle branch block or transient HG-AVB). Among them, the rate of long-term PPM dependency was 57%.

Conclusion

Selective EPS testing may assist in the risk stratification of post-TAVI HG-AVB and in the guidance of PPM implantation, especially in patients with equivocal PPM indications post-TAVI.

Evaluation of the 2021 European Society of Cardiology guidelines in pre-existing right bundle branch block patients undergoing transcatheter aortic valve implantation with a balloon-expandable valve

Aims

The 2021 European Society of Cardiology guidelines recommend early pacemaker implantation in pre-existing right bundle branch block (RBBB) patients who develop PR prolongation or QRS axis change after transcatheter aortic valve implantation (TAVI). We aimed to evaluate this recommendation in TAVI recipients with a balloon-expandable valve (BEV).

Methods and results

We retrospectively reviewed 188 pre-existing RBBB patients without pre-existing permanent pacemaker (PPM) who underwent TAVI with a BEV at our institution in 2015–19. Patients who developed high-degree atrioventricular block (HAVB) during TAVI or within 24 h post-TAVI were excluded. Eligible patients were divided according to the guideline-directed criteria (ΔPR interval ≥20 ms and/or QRS axis change). Patients who met the criteria (n = 102, 54.3%), compared with those who did not (n = 86), had a higher prevalence of baseline right axis deviation and were more likely to have received a larger valve with greater oversizing. The 30-day delayed HAVB rate did not differ significantly between the groups (3.9% vs. 4.7%, P = 1.00; odds ratio = 0.84, 95% confidence interval = 0.20–3.45). There was also no significant difference in terms of death (5.0% vs. 8.4% at 1 year; overall log-rank P = 0.94) or a composite of death or PPM implantation (14.8% vs. 16.6% at 1 year; overall log-rank P = 0.94) during follow-up post-TAVI. The majority of PR prolongations (79.4%) and QRS axis changes (52.0%) regressed within the following 24 h.

Conclusion

The present data did not demonstrate an association of significant changes in PR interval or QRS axis with heightened delayed HAVB risk in BEV recipients with pre-existing RBBB. Prospective studies are warranted to confirm these findings.

Delayed Total Atrioventricular Block After Transcatheter Aortic Valve Replacement Assessed by Implantable Loop Recorders

OBJECTIVES

The aims of this study were to evaluate the rate and time course of delayed total atrioventricular block (DT-AVB) after transcatheter aortic valve replacement (TAVR) using continuous electrocardiographic monitoring by implantable loop recorders and to identify potential predictors.

BACKGROUND

DT-AVB has been defined as onset more than 2 days after TAVR or after hospital discharge and is reported in 10% to 15% of patients at 30-day follow-up. To date, there is no standardized diagnostic and therapeutic algorithm to manage TAVR patients at risk for DT-AVB.

METHODS

Consecutive patients undergoing TAVR and simultaneous electrophysiologic testing without persistent or recurrent total atrioventricular block within 48 hours after the procedure underwent loop recorder implantation for full disclosure of atrioventricular conduction during 12-month follow-up.

RESULTS

DT-AVB occurred in 7 of 59 patients (11.9%), with onset between 2 days and 3 months after the procedure. Both prolongation of the PQ interval between baseline and day 2 after TAVR (OR: 1.04; 95% CI: 1.01-1.09); P = 0.032) and prolongation of the HV interval during the procedure (OR: 1.07; 95% CI: 1.02-1.14; P = 0.015) significantly predicted the onset of DT-AVB.

CONCLUSIONS

TAVR was associated with a considerable rate of DT-AVB of nearly 12% in this series. Prolongation of the PQ interval between baseline and day 2 and intraprocedural prolongation of the HV interval were significant predictors of DT-AVB.

Non-invasive predictors for infranodal conduction delay in patients with left bundle branch block after TAVR

AIMS

Left bundle branch block (LBBB) is the most common conduction disorder after transcatheter aortic valve replacement (TAVR) with an increased risk of atrioventricular (AV) block. The aim of the current study was to identify non-invasive predictors for infranodal conduction delay in patients with LBBB.

METHODS

We analyzed consecutive patients undergoing TAVR with pre-existing or new-onset LBBB between August 2014 and August 2020. His ventricular (HV) interval measurement was performed on day 1 after TAVR. Baseline, procedural, as well as surface and intracardiac electrocardiographic parameters were included. Infranodal conduction delay was defined as HV interval > 55 ms.

RESULTS

Of 825 patients screened after TAVR, 151 patients (82 ± 6 years, 39% male) with LBBB were included. Among these, infranodal conduction delay was observed in 25%. ΔPR (difference in PR interval after and before TAVR), PR and QRS duration after TAVR were significantly longer in the group with HV prolongation. In a multivariate analysis in patients with sinus rhythm (n = 123), ΔPR (OR per 10 ms increase: 1.52; 95%CI: 1.19-2.01; p = 0.002) was the only independent factor associated with infranodal conduction delay. A change in PR interval by 20 ms yielded a specificity of 83% and a sensitivity of 46%, with a negative predictive value of 84% and a positive predictive value of 45% to predict HV prolongation.

CONCLUSIONS

Simple analysis of surface ECG and a calculated ΔPR < 20 ms can be used as predictor for the absence of infranodal conduction delay in post-TAVR patients with LBBB.