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Imaging left ventricular tissue mechanics and hemodynamics during supine bicycle exercise using a combined tagging and phase‐contrast MRI pulse sequence
Author(s) -
Sampath Smita,
Derbyshire John Andrew,
LedesmaCarbayo Maria J.,
McVeigh Elliot R.
Publication year - 2011
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.22668
Subject(s) - supine position , cardiology , magnetic resonance imaging , hemodynamics , stroke volume , medicine , diastole , cardiac cycle , isovolumic relaxation time , heart rate , blood pressure , radiology , doppler echocardiography
Abstract Imaging the left ventricular mechanical and hemodynamic response to the stress of exercise may offer early prognosis in select patients with cardiac disease. Here, we demonstrate the feasibility of obtaining simultaneous measurements of longitudinal strain and transvalvular blood velocity during supine bicycle exercise stress in a wide bore magnetic resonance scanner. Combining information from the two datasets, we observe that although the time to peak strain (33.28 ± 1.86 versus 25.7 ± 2.12 as % of R–R interval) and time to peak mitral inflow velocity (44.37 ± 5.21 versus 35.5 ± 4.19 as % of R–R interval) from R‐wave of the QRS complex occurred earlier during stress, the time from peak strain to peak mitral inflow velocity was not statistically different (16.5 ± 3.23 versus 13.4 ± 3.06). Further, the percentage of longitudinal relaxation at peak mitral inflow velocity was higher during stress (63.5 ± 7.72 versus 84.32 ± 6.24). These results suggest that although diastole is shortened, early diastolic filling efficiency is augmented during exercise stress in normal volunteers in an effort to maintain stroke volume. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.