Pacing for Hypertrophic Obstructive Cardiomyopathy
Research type
Research Study
Full title
Mechanisms & Innovations in Right Ventricular Pacing for Hypertrophic Obstructive Cardiomyopathy (HOCM)
IRAS ID
298683
Contact name
Zachary Whinnett
Contact email
Sponsor organisation
JRCO - Imperial College London and Imperial College Healthcare NHS Trust
Clinicaltrials.gov Identifier
Duration of Study in the UK
2 years, 11 months, 28 days
Research summary
Summary of Research
Hypertrophic Cardiomyopathy (HCM) is a common inherited heart condition, affecting one in five hundred people. Patients with HCM can go on to develop Hypertrophic Obstructive Cardiomyopathy (HOCM) which causes the heart muscle to become abnormally thick causing obstruction of blood flow in the heart. This causes debilitating symptoms including shortness of breath, blackouts and chest pain. Current treatments are not ideal as the medication is often poorly tolerated or ineffective. Open heart surgery to remove thickened heart muscle can help but is very invasive and carries risks of complications. People with HOCM are prone to developing dangerous heart-rhythm disturbances which can cause death and so often have a device implanted to electrically shock the heart out of the dangerous heart rhythmn. These devices can also be used as pacemakers and are a promising treatment option, since they can alter the sequence of the heart muscle contraction thereby relieving the obstruction to the blood flow, making it easier for the heart to pump.
In this study I will recruit patients who already have a device or who are scheduled to have a device implanted. I will use high precision measurement techniques to assess whether adjusting the position of the pacing lead and the timing of the heart activation leads to improvements in heart function. The best position for the pacing lead and pacemaker settings may vary between individuals. I will therefore develop a technique for reliably identifying the most effective way to deliver this treatment to an individual person. I will also aim to establish how best to identify which people with HOCM are most likely gain benefit from this treatment. This treatment can then be tested in longer term studies to see if this is effective in relieving symptoms and improving the quality of life of people with hypertrophic cardiomyopathy.
Summary of Results
Obstructive Hypertrophic Cardiomyopathy (oHCM) is a common heart condition where the heart muscle becomes abnormally thickened. This causes obstruction of blood flow as it is pumped out of the heart to the rest of the body. This produces debilitating symptoms such as shortness of breath, chest pain and loss of consciousness. People with oHCM often have implantable cardioverter defibrillators (ICDs) implanted. These devices can be programmed to purposely pace the heart. Pacing the heart may help reduce the obstruction to the blood flow, as it can alter the sequence of heart muscle activation as well as the timing of the blood flow filling the heart.
In the EMORI-HCM clinical trial we investigated whether pacing the heart with optimum pacing settings can improve symptoms in patients with oHCM. Patient underwent an initial assessement where we identified what the optimal settings for their device should be. They also underwent baseline measurements of their symptoms, exercise ability and heart function. Patients were then randomly allocated to receive 3 months of optimal pacing followed by 3 months of no pacing. Or the converse of 3 months of no pacing followed by 3 months of optimal pacing. Patients were not aware of their device settings throughout the trial.
Sixty patients were recruited into the study over a 3 year period. Optimal pacing was found to improve patients' symptoms (measured with questionnaires and a daily symptom app) compared to no pacing. Optimal pacing also improved exercise capacity and walking distance compared to no pacing. Optimal pacing had no adverse effect on heart function in this 6 month study.
We therefore conclude that in patients with oHCM, optimal pacing improves symptoms and exercise capacity.REC name
West of Scotland REC 5
REC reference
21/WS/0169
Date of REC Opinion
21 Jan 2022
REC opinion
Further Information Favourable Opinion