- Poster presentation
- Open Access
Steep left ventricle to aortic root angle is independently associated with dynamic left ventricular outflow tract gradient in hypertrophic cardiomyopathy: a novel association using 3-dimensional multi-modality imaging
© Kwon et al; licensee BioMed Central Ltd. 2009
- Published: 28 January 2009
- Cardiac Magnetic Resonance
- Hypertrophic Cardiomyopathy
- Root Angle
- Left Ventricular Outflow Tract Gradient
- LVOT Obstruction
In HCM patients, we sought to determine if a steeper LVARA was associated with an increased LVOTG, independent of BSH.
We studied 153 consecutive patients (≤ 65 years) with echo-documented HCM who underwent standard CMR (1.5 T Siemens Avanto, Erlangen, Germany) along with whole-heart 3D MR angiogram which was a navigator-assisted free-breathing, ECG-triggered, fat saturated, T2-prepared, segmented 3D SSFP sequence. Imaging parameters were as follows: TR = 3.8 ms, TE = 1.9 ms, flip angle = 70°, acquired matrix = 175–216 (phase direction) by 256 (readout direction) points (no interpolation), Grappa factor of 2, 24 reference lines and sampling bandwidth = ± 125 kHz. Typically, 60–70 slices were acquired at 1.5 mm thickness (interpolated) in order to cover the heart. The in-plane resolution was typically 1.3–1.6 mm. Images were acquired during a 150 msec data acquisition window in mid-to-late diastole. LVARA, LV volumes (indexed to body surface area) and BSH were measured on CMR. Maximal (resting or provocable) LVOT gradients were recorded on echocardiography. Inter and intra-observer concordance of LV-aortic root angle measurement was assessed in 14 HCM patients using intraclass correlation coefficient (ICC).
Univariated and multivariate regression analysis testing the association between maximal LVOT gradient
Univariate Analysis Beta
Univariate Analysis p value
Multivariate Analysis Beta
Multivariate Analysis p value
Left ventricle to aortic root angle
End-systolic volume index
Beta blocker use
End-diastolic volume index
Basal end-diastolic interventricular septal thickness
In patients with HCM, a steeper LVARA predicts an increased LVOTG, independent of BSH. Steep LVARA, which likely represents accelerated remodelling of the LVOT, may explain why HCM patients with similar degree of BST have different degrees of dynamic LVOT obstruction. The prognostic importance of steep LVARA remains to be determined. This study demonstrates the clinical utility of multi-modality imaging, including CMR, in further understanding the varied phenotypic presentation and complex pathophysiology found in HCM.
This article is published under license to BioMed Central Ltd.