Conventional pacemakers involve placing a lead through a valve into the bottom right chamber of the heart. Research has shown that this approach is associated with an increased risk of valve dysfunction, mortality, and impairment of cardiac function.
Newer pacemakers, such as leadless pacemakers and pacemakers that engage directly with the heart's native conduction system (known as left bundle branch pacemakers), are increasingly being adopted. However, the impact of these newer pacing technologies on cardiac function and the tricuspid valve, as well as how they compare with each other, remains unclear.
The investigators aim to study the impact of leadless pacemakers and left bundle branch pacemakers on cardiac function and the tricuspid valve by conducting an acute study in addition to the routine pacemaker implantation procedure for which participants have been referred. Both procedures will be performed during a single session under general anaesthesia. Outcomes from this study will improve understanding of how these pacing technologies affect cardiac and valvular function and how they compare with each other. These findings will help guide decision-making regarding the optimal type of pacemaker to adopt, particularly for patients at greatest risk of developing tricuspid valve dysfunction or impaired cardiac function.
All patients aged ≥18 referred for a permanent pacemaker at a single centre (Guys and St. Thomas' NHS Foundation Trust, UK) with high degree AV block, including Mobitz II and complete heart block, or scheduled AV node ablation, and LVEF ≥50%.
LVEF <50%, severe TR, severe RV dysfunction, clinically unstable AV block requiring temporary pacing or isoprenaline infusion, left bundle branch block, previous TV annuloplasty or replacement, aortic valve replacement, life expectancy <1 year, end-stage renal failure, contraindication to cardiac MRI, CT or TOE, pregnancy, contraindication to anticoagulation, peripheral vascular disease precluding insertion of femoral catheters and insufficient capacity to consent to the study.
All patients referred for permanent pacemaker implantation with preserved LVEF at baseline.
Cohort
Cross-sectional
Temporary left bundle branch area pacing
Other interventionTemporary left bundle branch area pacing using a multielectrode catheter
Temporary leadless right ventricular pacing
Other interventionTemporary leadless right ventricular pacing using multielectrode catheter
Proportion of patients with acute pacemaker-induced cardiomyopathy
All patients will undergo intraprocedural transesophageal echocardiogram (TEE) and temporary left bundle branch area pacing (LBBAP) and leadless right ventricular pacing (LP). Measurements of left ventricular ejection fraction (LVEF) will be taken before and after each pacing configuration. A drop of \>\>10% in LVEF to an LVEF of \<50% will be considered as acute pacing induced cardiomyopathy (PIM).
Proportion of patients with tricuspid regurgitation (TR) progression
We will measure acute TR progression with intraprocedural TEE by assessing the degree of TR at baseline and with temporary pacing.A TOE probe will be inserted into the oesophagus after induction of general anaesthesia. Quantitative measurements taken will include RV end systolic volume (RVESV), RV end diastolic volume (RVEDV), RV global longitudinal strain (GLS), RV free wall strain, 3D RVEF and if TR is present, vena contracta diameter and PISA. Qualitative measurements will include upper-oesophageal, mid-oesophageal and 'grasping' view of the TV with colour doppler. TR severity will be assessed using the British Society of Echocardiography (BSE) guidelines and will be graded by semiquantitative visual grading (grade 0: none/trace, 1: mild, 2: moderate, 3: moderate-to-severe, 4: severe)60. TR progression will be defined as an increase in 1 grade.
Proportion of patients with right ventricular dsyfunction
A TEE probe will be inserted into the oesophagus after induction of general anaesthesia. Quantitative measurements taken will include RV end systolic volume (RVESV), RV end diastolic volume (RVEDV), RV global longitudinal strain (GLS), RV free wall strain and 3D RVEF. We will assess for acute RVD with TOE by measuring TAPSE, RVEF, RV GLS at baseline and with temporary pacing.
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Guy's and St Thomas' NHS Foundation Trust
Lead sponsor
King's College London
Collaborator
