Real-Time Magnetic Resonance Imaging to Study Orthostatic Intolerance Mechanisms in Human Beings: Proof of Concept.
Darius A GerlachAndrea B MaierJorge ManuelAnja BachAlex HoffJan-Niklas HönemannKarsten HeusserDirk VoitJens FrahmJens JordanJens TankPublished in: Journal of the American Heart Association (2022)
Background Discerning the mechanisms driving orthostatic symptoms in human beings remains challenging. Therefore, we developed a novel approach combining cardiac and cerebral real-time magnetic resonance imaging, beat-to-beat physiological monitoring, and orthostatic stress testing through lower-body negative pressure (LBNP). We conducted a proof-of-concept study in a patient with severe orthostatic hypotension. Methods and Results We included a 46-year-old man with pure autonomic failure. Without and during -30 mmHg LBNP, we obtained 3T real-time magnetic resonance imaging of the cardiac short axis and quantitative flow measurements in the pulmonary trunk and middle cerebral artery. Blood pressure was 118/74 mmHg during supine rest and 58/35 mmHg with LBNP. With LBNP, left ventricular stroke volume decreased by 44.6%, absolute middle cerebral artery flow by 37.6%, and pulmonary trunk flow by 40%. Conclusions Combination of real-time magnetic resonance imaging, LBNP, and continuous blood pressure monitoring provides a promising new approach to study orthostatic intolerance mechanisms in human beings.
Keyphrases
- magnetic resonance imaging
- middle cerebral artery
- blood pressure
- endothelial cells
- left ventricular
- heart rate
- computed tomography
- internal carotid artery
- induced pluripotent stem cells
- contrast enhanced
- pulmonary hypertension
- pluripotent stem cells
- heart failure
- heart rate variability
- atrial fibrillation
- mitral valve
- high resolution
- subarachnoid hemorrhage
- adipose tissue
- metabolic syndrome
- diffusion weighted imaging
- aortic valve
- mass spectrometry
- hypertrophic cardiomyopathy
- depressive symptoms
- sleep quality
- drug induced
- left atrial
- cerebral blood flow