Effect of His-Ventricular (HV) Interval Optimisation in Cardiac Resynchronisation Therapy

Study Overview
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Brief Summary
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Cardiac resynchronisation therapy (CRT) is a specialised type of pacemaker used in patients with severe heart failure to improve symptoms and survival. Approximately one third of patients treated with CRT do not notice significant improvement in their symptoms and this may be due to inadequate co-ordination between the upper and lower chambers of the heart (atrioventricular dyssynchrony). The investigators propose a new method to achieve atrioventricular synchrony in CRT based on measurements of electrical conduction from within the heart. Patients referred for CRT implantation at Castle Hill Hospital are eligible to participate. During CRT implantation, additional measurements, will be recorded from within the heart. After implantation, device settings will be adjusted to either standard or electrophysiologically-optimised settings with cross-over at 4 months. The investigators hypothesis is that patients with optimised settings will derive additional benefit compared to patients with standard pacemaker-determined settings.

Official Title
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A Randomised Cross-over Pilot Study of the Effect of His-Ventricular (HV) Interval Optimisation in Cardiac Resynchronisation Therapy

Conditions
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Heart Failure

Intervention / Treatment
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* Other: His-Ventricular (HV) optimisation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical diagnosis of heart failure Referred for cardiac resynchronisation therapy (CRT) with or without defibrillator In sinus rhythm Patients must have a telephone Ability to give informed consent Ability to complete the study Exclusion Criteria: Severe valve disease or previous valve replacement Previous atrial flutter ablation Chronic kidney disease Stage 3 or above Recent myocardial infarction Ongoing cardiac ischaemia Infiltrative cardiomyopathy Wolff-Parkinson White syndrome Presence of second or third degree heart block <90% biventricular pacing at 3 months Hypertrophic cardiomyopathy Pregnancy or breastfeeding On treatment for hypothyroidism or hyperthyroidism

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: His-Ventricular (HV)-optimised<br>His-Ventricular (HV) optimised atrioventricular delay | Other: His-Ventricular (HV) optimisation<br>* Optimisation of atrioventricular pacing interval<br>|
| No Intervention: Non-optimised<br>Standard atrioventricular delay | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in amino-terminal pro-B-type natriuretic peptide (NT-proBNP) |  | 7 months and 11 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Increase in 6-min walk test distance by ≥25 m |  | 7 months and 11 months | 
| ≥5points improvement in the short Kansas City Cardiomyopathy Questionnaire score |  | 7 months and 11 months | 
| Reduction of left ventricular end-diastolic volume. |  | 7 months and 11 months |