Mechanisms and Innovations in Cardiac Resynchronisation Therapy

Not Applicable

Completed

• Conditions: Right Bundle-Branch Block; Heart Failure; Left Ventricular Systolic Dysfunction; Left Bundle-Branch Block; Non-Specific Intraventricular Conduction Defect
• Interventions: Device: His-bundle pacing.

• Registration Number: NCT04221763
• Lead Sponsor: Imperial College London

Brief Summary

The aim of this study is to compare the effectiveness of multiple modalities of cardiac resynchronisation therapy using high precision acute electrical and haemodynamic measurements.These modalities include biventricular pacing and conduction system pacing utilising His bundle and left bundle pacing. Conduction system pacing is a more physiological form of pacing. The study hypothesises that this will produce more effective cardiac resynchronisation.

Detailed Description

This is a single centre acute electrical/haemodynamic and observational study of a subgroup of patients with heart failure. A total of 60 will be recruited. The acute study involves within patient comparison of biventricular and conduction system pacing using detailed electrical mapping and high precision haemodynamic measurement protocol.

Participants will have permanent conduction system pacing if;

* Baseline left bundle branch block and QRS \> 140ms or QRS \>150ms and any QRS morphology AND

* Conduction system pacing is successful at reducing QRS duration by 20ms or more with satisfactory pacing parameters.

Participants who receive permanent conduction system pacing will have follow up at 6 weeks, 3 months, 6 months and 12 months. Non-invasive markers including mechanical activation pattern (echocardiography and cardiac MRI) and electrical activation pattern (ultra-high frequency electrocardiography) will be used to identify the characteristics of patients who benefit from conduction system pacing.

Study Timeline

• Study Start: 2019-10-15
• Study First Submitted: 2019-11-04
• Study First Submitted QC: 2020-01-06
• Study First Posted: 2020-01-09
• Primary Completion: 2022-12-01
• Study Completion: 2022-12-01
• Status Verified: 2023-03
• Last Update Submitted: 2023-03-21
• Last Update Posted: 2023-03-22

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 47

Inclusion Criteria

• Patients referred for conventional CRT
• Severe heart failure (LVEF, a measure of heart pumping, < 35% - severe)
• Prolonged QRS duration (>120ms)
• Adults willing to take part (age > 18 years)
• Able to give consent

Exclusion Criteria

• Unable to give consent
• Children (age < 18 years)
• Pregnant women

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Heart failure and abnormal cardiac conduction	His-bundle pacing.	Subjects will have an attempt at His-bundle pacing, left bundle pacing and biventricular pacing. Pacing at the His bundle and the left bundle will be attempted using a Medtronic SelectSecure™, Model 3830 lead. Delivery of the lead utilizes a deflectable sheath, the Medtronic SelectSite™, Model C304. Biventricular pacing will utilise a left ventricular lead placed in the coronary sinus using any of the 5 manufactures of CS leads Biotronik, Boston Scientific, Medtronic, Sorin, and St. Jude Medical or in participants receiving permanent conduction system pacing left ventricular pacing will be achieved using a Cordis ATW™ wire placed in the coronary sinus.

Primary Outcome Measures

Name	Time	Method
Acute electrical measurements	20 minutes	Mean change in left ventricular activation time (Milliseconds) (measured using ECGI) during AV sequential CRT pacing (HBP, LBP, epiBVP and combined HPB with epiLVP) at optimal AV delay measured in Milliseconds.
Acute change is systolic blood pressure	20 minutes	Mean change in systolic blood pressure (mmHg) from atrial pacing to AV sequential CRT pacing (HBP, LBP, epiBVP and combined HPB with epiLVP) at optimal AV delay measured in mmHg.

Secondary Outcome Measures

Name	Time	Method
Conduction system battery longevity	6 weeks, 3 months, 6 months, 12 months.	The measurements include battery longevity measured in months.
Conduction system lead threshold	6 weeks, 3 months, 6 months, 12 months.	The measurements include lead threshold to achieved QRS narrowing measured in Volts at 0.5ms and 1ms.
Left ventricular ejection fraction	12 months	Patients with permanent conduction system leads will undergo a repeat echocardiography and measure their left ventricular ejection fraction.
Cardiopulmonary exercise testing	6 months	Patients with permanent conduction system leads will undergo symptom assessment with a repeat cardio-pulmonary exercise test to measure MVO2 in litres/minute.
Heart failure symptoms	6 months	Heart failure symptoms of patients with permanent conduction system leads will be assessed at follow up at 3 month, 6 months and 12 months. The symptoms will be assessed using the Minnesota living with heart failure questionnaire score.

Trial Locations

Locations (1)

Hammersmith Hospital Imperial College NHS trust; 🇬🇧 London, United Kingdom