SyncAV™ Study - V1.1
Research type
Research Study
Full title
Assessing the Effect of the SyncAV™ Algorithm in Cardiac Resynchronization Therapy on Exercise Capacity and QRS Duration on Exercise
IRAS ID
245366
Contact name
Neil Herring
Contact email
Sponsor organisation
University of Oxford, Clinical Trials and Research Governance
Duration of Study in the UK
2 years, 0 months, 16 days
Research summary
Summary of Research
In patients with weak pumping function of the heart, uncoordinated contraction of the chambers can be corrected using a cardiac resynchronization therapy (CRT) pacemaker. These devices make patients live longer by improving how the heart pumps and reducing symptoms such as breathlessness. However, not all patients benefit from CRT and programming devices optimally can greatly influence success. Predicting the correct timings of contraction between the atria (top chambers of the heart) and the ventricles (bottom chambers), as well as between the left and right ventricles, especially when heart rate increases during exercises, is challenging.A new approach to optimizing CRT programming has been proposed known as ‘fusion-pacing’. This allows the electrical wave from the heart’s own conduction system to merge or fuse with the impulse from the pacemaker in the left ventricle. The timing of the pacemaker’s impulse is continuously adjusted to measurements the device makes of the hearts natural conduction. What is not clear is how effective ‘fusion-pacing’ is during exercise when the hearts natural conduction changes rapidly and unpredictably. We plan to investigate this by monitoring the ECG whilst accurately measuring exercise performance and ability during a cardiopulmonary exercise test (CPET) on an exercise bike. We will also ask participants to rate their perceived exercise intensity to see whether fusion pacing improves ECG resynchronization, exercise performance, and patients' symptoms compared to standard programming. Twenty participants with CRTs will undergo two CPET tests 2 weeks apart, with programming randomised and blinded on both occasions.
Participants will be recruited from patients with qualifying CRT devices under active follow up at Oxford University Hospitals NHS Foundation Trust. Recruitment and data analysis will take place over a 2 year period.
Summary of Results
In patients with weak pumping function of the heart, uncoordinated contraction of the chambers can be corrected using a cardiac resynchronization therapy (CRT) pacemaker. These devices make patients live longer by improving how the heart pumps and reducing symptoms such as breathlessness. However, not all patients benefit from CRT and programming devices optimally can greatly influence success. Predicting the correct timings of contraction between the atria (top chambers of the heart) and the ventricles (bottom chambers), as well as between the left and right ventricles, especially when heart rate increases during exercises, is challenging.
A new approach to optimizing CRT programming has been proposed known as ‘fusion-pacing’. This allows the electrical wave from the heart’s own conduction system to merge or fuse with the impulse from the pacemaker in the left ventricle. The timing of the pacemaker’s impulse is continuously adjusted to measurements the device makes of the hearts natural conduction. What is not clear is how effective ‘fusion-pacing’ is during exercise when the hearts natural conduction changes rapidly and unpredictably.We investigated this by monitoring the electrocardiogram (ECG) whilst accurately measuring exercise performance and ability during a cardiopulmonary exercise test (CPET) on an exercise bike, comparing fusion pacing with standard fixed atrioventricular delay (AVD) settings. We found that fusion pacing is maintained during exercise without impairing exercise capacity compared to fixed AVD. However, using whichever algorithm gives the best ECG at rest (the narrowest QRS duration) is associated with a maintained narrower QRSd during exercise and this is turn is associated with an improvement in measures of exercise capacity and performance
REC name
South Central - Oxford B Research Ethics Committee
REC reference
18/SC/0611
Date of REC Opinion
22 Nov 2018
REC opinion
Favourable Opinion