Clinical Trial: Biventricular Pacing in Hypertrophic Cardiomyopathy
Study Status: Completed
Recruit Status: Unknown status
Study Type: Interventional
Official Title: Diastolic Ventricular Interaction and the Effects Of Biventricular Pacing in Hypertrophic Cardiomyopathy
Brief Summary:
Hypertrophic Cardiomyopathy is an inherited condition characterized by thickening (hypertrophy) of the heart muscle. Many patients who have this condition have a reduced ability to exercise because of breatlessness, which can in some cases be severe. This appears in most cases to be due to an impairment of the filling of the heart, especially on exercise this limits the amount of blood the heart is able to pump. Several factors may contribute to this slow filling of the heart, including (1) The heart contracts and relaxes in an incoordinate way (called 'dyssynchrony') which is inefficient, and (2) The filling of the main pumping chamber (the left ventricle) may be impeded by high pressure in the other ventricle(the right ventricle)- in other words the left ventricle is 'squashed' by the right ventricle. This is known as diastolic ventricular interaction.
Although drugs can improve the filling of the heart and relieve symptoms, some patients remain very symptomatic despite these drugs.
The mechanisms responsible for the filling abnormality in patients with Hypertrophic Cardiomyopathy are similar to those seen in the much more common condition known as Heart Failure. A special type of pacemaker technique called 'Biventricular Pacing' has been shown to markedly improve symtoms in patients with heart failure. This form of pacing has been shown to improve both 'dyssynchrony' ( incoordination) and 'ventricular interaction' (squashed left heart) in patients with Heart Failure.
We propose that Biventricular pacing may similarly improve these abnormalities in patients with Hypertrophic Cardiomyopathy, resulting in an improvement of symptoms. The study will focus on patients with the condition who have severe symtoms despite being on optimal currently available drug therapy.
Detailed Summary:
SUBJECTS Forty Participants, who fufil the entry criteria, will be selected. These Participants will be recruited from Cardiomyopathy clinics run at two sites. These are the Cardiomyopathy Clinics at the Heart Hospital, University College London, and from the Queen Elizabeth Hospital, Birmingham.
CONSENT Written informed consent will be obtained from all participants.
CLINICAL ASSESSMENT
A History will be taken and a Clinical Examination will be carried out. A validated Quality of life questionaire will be completed ( Minnesota Living with Heart Failure).
Maximal Cardiopulmonary exercise testing will be performed on a treadmill, with breath by breath respiratory gas sampling, using a face mask.
A 12 lead ECG will be obtained. 48hr Ambulatory Heart Rhythm Monitoring
CARDIAC ULTRASOUND SCAN ASSESSMENT
To assess the function of the Heart during its contraction and filling phases, including the degree of incoordination of the Heart muscle.
PACEMAKER IMPLANTATION
A pacemaker capable of Biventricular pacing will be implanted, using a standard established technique at one of three sites ( The Heart Hospital London, St Peters Hospital Chertsey, or Queen Elizabeth Hospital Birmingham ).
24hr POST PACEMAKER IMPLANT. Assessment of mechanical dyssynchrony will be made using Ultrasound techniques which will include 2D/ M mode Echocardiography, Doppler studies, and Tissue doppler imaging. This assessment will be made with the Pacemaker off, and
Sponsor: University Hospital Birmingham
Current Primary Outcome: Peak Exercise Oxygen Consumption. [ Time Frame: 4 month ]
Original Primary Outcome: Same as current
Current Secondary Outcome:
- Myocardial Asynchrony Index [ Time Frame: 4 months ]
- Minnesota Quality of Life Questionnaire [ Time Frame: 4 months ]
Original Secondary Outcome: Same as current
Information By: University Hospital Birmingham
Dates:
Date Received: July 18, 2007
Date Started: June 2006
Date Completion: August 2008
Last Updated: July 18, 2007
Last Verified: July 2007
