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- Open Access
Exercise capacity predictors in hypertrophic obstructive cardiomyopathy patients assessed by multi-modality imaging
© Austin et al; licensee BioMed Central Ltd. 2010
- Published: 21 January 2010
- Cardiac Magnetic Resonance
- Mitral Regurgitation
- Exercise Capacity
- Pulse Wave Velocity
- Aortic Stiffness
In HCM, with progression of disease, there is often a reduction in exercise capacity, likely due to diastolic dysfunction, mitral regurgitation (MR) and dynamic left ventricular outflow tract obstruction (LVOTO). However, there is considerable variation in exercise capacity despite similar diastolic dysfunction, LVOTO and MR. Aortic stiffness could be a possible contributor in HCM pathophysiology. Pulse wave velocity (PWV), measured by cardiac magnetic resonance (CMR), is a marker of aortic stiffness and is abnormal in HCM vs. controls.
To test the association between maximal oxygen consumption (VO2 max) and various clinical/imaging predictors in hypertrophic cardiomyopathy (HCM) patients with preserved ejection fraction.
Fifty consecutive, newly referred HCM patients (62% men, 44 +/- 13 years, 78 % on beta-blockers, 18 % hypertensives) underwent Doppler echocardiography (echo), cardiopulmonary exercise testing and CMR (1.5 T, Siemens, Erlangen, Germany) for symptom evaluation. Deceleration time (DT), myocardial performance index (MPI or isovolumic contraction time + isovolumic relaxation time/ejection time), post exercise MR and LVOT gradient (mm Hg) were measured on echo. VO2 max (ml/kg/minute) was measured. LV volumetric indices and PWV were measured on CMR. PWV (m/s) was measured as follows: Δx/Δt (Δx = aortic path length between mid-ascending and mid-descending aorta measured on Half Fourier Acquisition in Steady State images and Δt = time delay between arrival of foot of PW between 2 points on velocity encoded images).
Pulse wave velocity
Body surface area
Myocardial performance index
Maximal post stress LVOT gradient
Post-stress mitral regurgitation
Basal end-diastolic interventricular septal thickness
In HCM patients, aortic stiffness likely explains additional variations in exercise capacity, over and above LV thickness, MR, LVOTO and diastolic indices. Aortic stiffness is a potential therapeutic target in assessing improvements in exercise capacity in HCM patients.
This article is published under license to BioMed Central Ltd.