An interventional study of Active pacing and Back-up pacing in Cardiomyopathy, Hypertrophic, sponsored by Barts & The London NHS Trust. Completed at 1 site in United Kingdom. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2023-02-01.
Sponsored by Barts & The London NHS Trust · Not applicable, Interventional, and Treatment
The main aim of this study is to assess the acute effects of a pacemaker on reducing abnormally high intracavity pressures in the hearts of patients with mid-cavity obstructive hypertrophic cardiomyopathy (HCM). During a 12-month period of double-blinded follow-up, descriptive data will be collected on patients symptomatic and physical performance during dichotomous pacemaker settings for 6-months each (active and back-up). The statistical information collected will be used to design a much larger research trial of patient benefit.
Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease, affecting 1 in 500 of the general population. It is characterised by abnormal thickening of the heart muscle. The various patterns of thickening of the muscle in the main pumping chamber, or left ventricle (LV), can result in obstruction to blood flow within the heart, raising the pressures in the heart and placing extra strain on the heart muscle.
The obstruction can cause patients to suffer from symptoms such as shortness of breath and chest pain, along with poor exercise tolerance, and dizzy spells. In very symptomatic patients with the commonest type of obstruction, invasive procedures performed either via an open-heart or keyhole operation can reduce the increased basal septal muscle mass at the point of obstruction. However, in around 1 in 10 HCM patients, the obstruction is deep within the LV where a ring of thick muscle blocks blood flow when it contracts. These patients provide a challenge for doctors, as this type of obstruction is much less suitable for open heart or keyhole operation.
An alternative is to use a cardiac pacemaker to alter the timing of the contraction in the ring of thick muscle such that different parts of the ring contract at different times and thereby reduce obstruction to blood flow. The investigators' early experience with this new treatment shows that carefully placing the pacemaker wires can reduce the obstruction and improve patient symptoms.
Key questions of this research include:
Exclusion Criteria:
Active ventricular pacing. The pacemaker is set-up with a short atrio-ventricular delay to allow for appropriate pacing capture of the ventricle.
Device: Active pacing
Back-up pacing. The pacemaker is set-up to sense and pace only in the right atrium (AAI) without any pacing capacity in the ventricle.
Device: Back-up pacing
Ventricular pacing via the invasive haemodynamic study-defined optimal pacing site in order to relieve pressure gradient across the mid-cavity obstruction in mid-cavity obstructive variant hypertrophic cardiomyopathy.
Back-up pacing. The pacemaker is set-up to sense and pace only in the right atrium (AAI) without any pacing capacity in the ventricle.
Invasive gradient (mmHg)
Acute invasively defined gradient change in mmHg across the mid-cavity with optimal ventricular pacing setting
Time frame: Measured during pacemaker implant. Pressure gradients will be measured at different pacing sites during the implant.
Symptomatic assessment via SF36 questionnaire
Generalised health related questionnaire
Time frame: Pre-implant, 4 months, and 8 months
Symptomatic assessment via Kansas City Cardiomyopathy questionnaire
Cardiomyopathy health related questionnaire
Time frame: Pre-implant, 4 months, and 8 months
Symptomatic assessment via calculation of New York Heart Association (NYHA) functional class
Classification of extent of heart failure
Time frame: Pre-implant, 4 months, and 8 months
Exercise performance assessed by 6 minute walk test (6MWT)
Sub-maximal exercise test
Time frame: Pre-implant, 4 months, and 8 months
Exercise performance assessed by Cardiopulmonary exercise testing (CPET) stress echocardiography.
Maximal exercise test with simultaneous echocardiography
Time frame: Pre-implant, 4 months, and 8 months
Levels of Brain Natriuretic Peptide
Protein associated with heart failure
Time frame: Pre-implant, 4 months, and 8 months
This study is completed, as verified in Feb 2023. You cannot join it, but the record below documents what was studied.
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Barts & The London NHS Trust