None listed
Conditions
Brief summary
This study is a pilot to measure the maximum heart rate possible cycling in the supine position to gain experience to plan future cardiac magnetic resonance imaging (MRI) studies using exercise stress for the assessment of patients with coronary artery disease (CAD). Typical exercise stress tests are often conducted walking upright using treadmills. Imaging at peak heart rates are limited by delays as participants are moved from the treadmill into the image position. Supine exercise removes this delay. However it is not well known what heart rates are possible in this position as fewer muscle groups are engaged. In this study heart rate data from the supine position will be compared against that obtained by treadmill for each participant and the hearts function will be assessed using MRI. Ventricular function and aortic pulse wave velocity (PWV) and distensibilty measurements will be assessed, both at rest and peak heart rates.
Interventions
Participants will initially undergo an upright treadmill exercise assessment. A modified protocol will be used consisting of a 2 minute warm-up period at slow walking pace, followed by ramped increase of both treadmill speed and inclination to reach maximum age predicted heart rate in 5-8 minutes. Once maximum heart rate is reached participants will step to the side of the treadmill for 15 seconds rest, before starting again for another 30 seconds. This is repeated 8 times to simulate the pauses
Participants will initially undergo an upright treadmill exercise assessment. A modified protocol will be used consisting of a 2 minute warm-up period at slow walking pace, followed by ramped increase of both treadmill speed and inclination to reach maximum age predicted heart rate in 5-8 minutes. Once maximum heart rate is reached participants will step to the side of the treadmill for 15 seconds rest, before starting again for another 30 seconds. This is repeated 8 times to simulate the pauses needed during the MRI assessment. During a second clinic session 2-14 days later, participants will be placed in an MRI and undergo a resting scan, followed by a scan during exercise where they will be asked to pedal in the supine position while still in the scan position. The exercise protocol begins with a 2 minute warm-up period pedalling at 60-90 rpm with no resistance. The resistance is then increased to achieve maximum exercise in 5-8 minutes. Once maximum exertion is reached participants stop pedalling for 10 seconds for MRI image acquisition and then begin pedalling again for a further 30 seconds before stopping again for another acquisition. This is repeated 8 times to acquire all required images.
Sponsors
University of Auckland
Study design
Allocation
Non-randomised trial
Primary purpose
Diagnosis
Eligibility
Sex/Gender
All
Age
20 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
healthy controls aged 20-75
Exclusion criteria
Pregnancy, contraindication to MRI, atrial fibrillation, physical limitations preventing treadmill or cycle exercise, known cardiovascular disease - especially CAD, hypertensive (treated or untreated) - resting blood pressure (supine) above 160/100 mmHg.
Outcome results
None listed