Aortic valve implantation-induced conduction block as a framework towards a uniform electrocardiographic definition of left bundle branch block

Introduction

New-onset left bundle branch block (LBBB) following transcatheter or surgical aortic valve replacement (LBBB_AVI) implies a proximal pathogenesis of LBBB. This study compares electrocardiographic characteristics and concordance with LBBB definitions between LBBB_AVI and non-procedure-induced LBBB controls (LBBB_control).

Methods

All LBBB_AVI patients at Ghent University Hospital between 2013 and 2019 were enrolled in the study. LBBB_AVI patients were matched for age, sex, ischaemic heart disease and ejection fraction to LBBB_control patients in a 1:2 ratio. For inclusion, a non-strict LBBB definition was used (QRS duration ≥ 120 ms, QS or rS in V1, absence of Q waves in V5-6). Electrocardiograms were digitally analysed and classified according to three LBBB definitions: European Society of Cardiology (ESC), Strauss and American Heart Association (AHA).

Results

A total of 177 patients (59 LBBB_AVI and 118 LBBB_control) were enrolled in the study. LBBB_AVI patients had more lateral QRS notching/slurring (100% vs 85%, p = 0.001), included a higher percentage with a QRS duration ≥ 130 ms (98% vs 86%, p = 0.007) and had a less leftward oriented QRS axis (−15° vs −30°, p = 0.013) compared to the LBBB_control group. ESC and Strauss criteria were fulfilled in 100% and 95% of LBBB_AVI patients, respectively, but only 18% met the AHA criteria. In LBBB_control patients, concordance with LBBB definitions was lower than in the LBBB_AVI group: ESC 85% (p = 0.001), Strauss 68% (p < 0.001) and AHA 7% (p = 0.035). No differences in electrocardiographic characterisation or concordance with LBBB definitions were observed between LBBB_AVI and LBBB_control patients with lateral QRS notching/slurring.

Conclusion

Non-uniformity exists among current LBBB definitions concerning the detection of proximal LBBB. LBBB_AVI may provide a framework for more consensus on defining proximal LBBB.

Supplementary Information

The online version of this article (10.1007/s12471-021-01565-8) contains supplementary material, which is available to authorized users.

P309Aortic valve implantation-induced bundle branch block as a framework towards a more uniform electrocardiographic definition of left bundle branch block

INTRODUCTION

The electrocardiographic (ECG) pattern of true left bundle branch block (LBBB) has not been fully clarified and various definitions of LBBB exist. New-onset LBBB after transcatheter (TAVR) or surgical (SAVR) aortic valve replacement implies a proximal pathogenesis of LBBB and thus may provide a reference to characterize and define true LBBB.

PURPOSE

This study compares ECG characteristics in aortic valve implantation-induced LBBB (AVI-LBBB) to a non-procedural-induced LBBB control group (co-LBBB) in order to set a more homogenous definition for true LBBB.

METHODS

The study enrolled all patients with new-onset TAVR- and SAVR-induced LBBB between 2013 and 2019. AVI-LBBB was defined as new-onset persistent LBBB occurring within 24h after TAVR or SAVR. Patients were matched for age, sex, ischemic heart disease and left ventricular systolic function to randomly selected co-LBBB patients in a 1:2 ratio. For inclusion in both groups, a non-strict LBBB definition was used (QRSD ≥120ms, QS or rS in lead V1, absence of Q wave in leads V5-6). ECG characteristics were digitally analysed by the MUSE algorithm and confirmed by two experts. All ECG recordings were classified according to 4 different LBBB definitions: MADIT, European Society of Cardiology (ESC), Strauss and American Heart Association (AHA).

RESULTS

59 patients with AVI-LBBB (34 TAVR, 25 SAVR, median age 82 years, 42% male) were compared to 118 matched co-LBBB patients.

All patients with AVI-LBBB presented with QRS notching/slurring in the lateral leads, whereas this was present in only 85% of the co-LBBB group (p = 0.001). QRS duration (148ms vs 145ms, p = 0.074) and R wave peak time (58ms vs 62ms, p = 0.065) were not significantly different among both groups. AVI-LBBB was characterized by a more rightward QRS axis (-15° vs -30°, p = 0.013). When comparing AVI-LBBB to LBBB controls with QRS notching/slurring, a comparable QRS axis was observed.

Almost all AVI-LBBB patients met the MADIT (98%), ESC (100%) and Strauss (95%) definition. Only 18% of patients met the AHA definition, because of the low combined presence of QRS notching/slurring in all 4 lateral leads (54%) and because only 27% of patients had an R wave peak time &gt;60ms in both leads V5-6.

In the co-LBBB group, adherence to the different definitions was significantly lower compared to the AVI-LBBB group: MADIT 86% (p = 0.007), ESC 85% (p = 0.001), Strauss 68% (p &lt; 0.001) and AHA 7% (p = 0.035). Lower presence of lateral notching/slurring and more patients with smaller QRS duration (QRS duration ≥130ms, 86% vs 98%, p = 0.007) in the co-LBBB group explain these results.

CONCLUSIONS

Discordance exists between various definitions in scoring AVI-LBBB. Our data show that presence of QRS notching/slurring in the lateral leads is a crucial feature of proximal LBBB, rather than QRS duration and R wave peak time. The AVI-LBBB population provides a framework towards a more uniform definition and criteria for assessing true, proximal LBBB.

6119Correction of transcatheter aortic valve replacement induced left bundle branch block by His bundle pacing

Background

Left bundle branch block (LBBB) occurs frequently after transcatheter aortic valve replacement (TAVR) and is associated with increased risk of permanent pacemaker implantation, heart failure hospitalization and sudden cardiac death. This pilot study explored the feasibility of TAVR-induced LBBB correction with His bundle pacing (HBP).

Methods

Patients with TAVR -induced LBBB and postoperative need for permanent pacemaker implant were planned for electrophysiology study and HBP. Patients with persistent high degree AV-block were excluded. HBP was performed using the Select Secure pacing lead, delivered through a fixed curve or a deflectable sheath. Successful HBP was defined as correction of LBBB by selective or non-selective HBP with LBBB correction thresholds less than 3.5V at 1.0ms at implant.

Results

The study enrolled 6 patients (mean age 85±2.5 years, 50% male). Mean QRS duration was 152±10ms, PR-interval 212±12ms AH-interval 166±16ms and HV-interval 62±12ms. Successful HBP was achieved in 5/6 (83%) patients. Mean QRS duration decreased from 153±11ms to 88±14ms (p=0.002). At implantation, mean threshold for LBBB correction was 1.6±1.0V (unipolar) and 2.2±1.3V (bipolar) at 1.0ms. Periprocedural, two complete AV-blocks occurred, both spontaneously resolved by the end of the procedure. Thresholds remained stable at 1 month follow up: 1.8±1.0V (unipolar) and 2.3±1.5V (bipolar) at 1.0ms.

Figure 1

Conclusion

Permanent His bundle pacing can safely correct TAVR-induced LBBB in the majority of patients. Further studies are needed to assess potential benefits of His bundle pacing over conventional right ventricular pacing in this population.

P576The first handheld device for autonomic self-detection of symptomatic acute coronary artery occlusion: feasibility, performance and implications for time-efficient self-triage of outpatients with CAD

Background

Time delay between onset of symptoms and seeking medical attention is a major determinant of mortality and morbidity in patients with acute coronary artery occlusion (ACAO). Response time might be reduced by reliable self-detection of ACAO. Currently no self-applicable device can accurately detect ACAO. We have recently shown that an automatic algorithm based upon a three lead system (RELF method) accurately detects ACAO.

Purpose

In this multicenter observational study we tested the operational feasibility, sensitivity and specificity of our RELF method, built into a mobile handheld device, for detection of ACAO.

Methods

Patients with planned elective percutaneous coronary intervention (PCI), who were able to use a smartphone, were asked to perform random ambulatory self-recordings for at least one week. A similar self-recording was made before angioplasty and at 60 s of balloon occlusion.

Results

The operational feasibility of ambulatory self-recordings in enrolled patients with CAD was 59/64 (92.1%, 95% CI: 83.0–96.6). Of all self-recordings 91.1% (n=4567) were automatically classified as successful within one minute. The mean false positive rate during daily life conditions was 4.19% (95% CI: 3.29–5.10). Amongst 65 balloon occlusions, 63 index-tests at 60 s of occlusion were available. The sensitivity for the target conditions “ACAO”, “ACAO with ECG changes” and “ACAO with ECG changes and ST segment elevation myocardial infarction (STEMI) criteria” was respectively 55/63 (0.87; 95% CI: 0.77–0.93), 54/57 (0.95; 95% CI: 0.86–0.98) and 35/35 (1.00). The figure depicts all (n=3936) ST difference vector (STDVn) measurements obtained during ambulatory postural changes, exercise and coronary artery occlusion with and without ECG changes and/or STEMI criteria. Receiver Operator Curve (ROC) for ACAO at different cut-off values of the magnitude of STDVn was 0.973 (95% CI: 0.956–0.990).

Boxplots of all STDVn test recordings

Conclusions

Self-recording with our RELF device is feasible for the majority of patients with CAD. The sensitivity and specificity for automatic detection of the earliest phase of acute coronary artery occlusion support the concept of our RELF device for patient empowerment to reduce delay and increase survival without overloading emergency services. This is the first clinical study that confirms the proof-of-concept of self-detection of acute coronary artery occlusion in outpatients with CAD.

Acknowledgement/Funding

Ghent University, Industrial Research Fund (IOF reference: F2015/IOF-advanced/084).

Air pollution and ST-elevation myocardial infarction: A case-crossover study of the Belgian STEMI registry 2009-2013

BACKGROUND

Previous studies have shown that air pollution particulate matter (PM) is associated with an increased risk for myocardial infarction. The effects of air pollution on the risk of ST-elevation myocardial infarction (STEMI), in particular the role of gaseous air pollutants such as NO₂ and O₃ and the susceptibility of specific populations, are still under debate.

METHODS

All patients entered in the Belgian prospective STEMI registry between 2009 and 2013 were included. Based on a validated spatial interpolation model from the Belgian Environment Agency, a national index was used to address the background level of air pollution exposure of Belgian population. A time-stratified and temperature-matched case-crossover analysis of the risk of STEMI was performed.

RESULTS

A total of 11,428 STEMI patients were included in the study. Each 10μg/m³ increase in PM10, PM2.5 and NO₂ was associated with an increased odds ratio (ORs) of STEMI of 1.026 (CI _95%: 1.005-1.048), 1.028 (CI _95%: 1.003-1.054) and 1.051 (CI _95%: 1.018-1.084), respectively. No effect of O₃ was found. STEMI was associated with PM10 exposure in patients ≥75y.o. (OR: 1.046, CI _95%: 1.002-1.092) and with NO₂ in patients ≤54y.o. (OR: 1.071, CI _95%: 1.010-1.136). No effect of air pollution on cardiac arrest or in-hospital STEMI mortality was found.

CONCLUSION

PM2.5 and NO₂ exposures incrementally increase the risk of STEMI. The risk related to PM appears to be greater in the elderly, while younger patients appear to be more susceptible to NO₂ exposure.

Iatrogenic left main coronary artery dissection

We present a case of iatrogenic left main coronary artery dissection, successfully treated by prompt bail-out stenting, and provide a brief discussion on its occurrence and treatment, as well as the immediate and long-term outcome of percutaneous coronary intervention, including our own single-centre experience, for this potentially catastrophic complication.