Author + information
- Received March 7, 2007
- Revision received July 16, 2007
- Accepted July 23, 2007
- Published online October 16, 2007.
- Barry A. Borlaug, MD⁎,⁎ (, )
- Vojtech Melenovsky, MD, PhD†,1,
- Margaret M. Redfield, MD, FACC⁎,
- Kristy Kessler, RN, BSN†,
- Hyuk-Jae Chang, MD, PhD†,
- Theodore P. Abraham, MD, FACC† and
- David A. Kass, MD, FACC†
- ↵⁎Reprint requests and correspondence:
Dr. Barry A. Borlaug, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, Minnesota 55905.
Objectives The aim of this study was to examine the relationship between individual components of left ventricular (LV) afterload and tissue Doppler echocardiography (TDE) velocities in humans.
Background Acute increases in afterload slow diastolic relaxation as assessed invasively, yet little is known about chronic effects of load and loading sequence on LV TDE velocities.
Methods Forty-eight subjects underwent echo Doppler and color-coded TDE with comprehensive noninvasive vascular assessment. Arterial afterload was measured by effective arterial elastance (Ea) and systemic vascular resistance index (SVRI), and loading sequence was quantified by early- (carotid characteristic impedance [Zc]) and late-systolic loads (augmentation index [cAI]; late pressure-time integral [PTI3]). Vascular stiffness was measured by carotid-femoral pulse wave velocity (PWV) and total arterial compliance.
Results Early-diastolic velocity (E′) varied inversely with Zc, SVRI, Ea, and PWV (r = −0.4 to 0.5; β = 1.0 to 1.2; p ≤ 0.004), but late-systolic load (cAI and PTI3 r = −0.6; β = 1.6; both p < 0.0001) and arterial compliance (r = 0.6; β = 1.4; p < 0.0001) had the strongest associations with E′. Load dependence was not altered by the presence of hypertension, and in multivariate analysis only cAI and Zc significantly predicted E′, even after adjusting for age (p < 0.05). Peak systolic velocity was additionally found to be inversely related to afterload, whereas other measures of contractility were not.
Conclusions Diastolic and systolic tissue velocities vary inversely with arterial afterload, with late-systolic load having the greatest influence on E′. These findings may partly explain the decrease in early relaxation velocity noted with aging, hypertension, and patients with heart failure. Strategies to reduce afterload, vascular stiffening, and wave reflections may prove useful to enhance early diastolic relaxation.
↵1 Dr. Melenovsky is also supported by grant MZO-0023001 from the State Department of Health, Czech Republic.
Supported by National Institutes of Health/National Institute on Aging grant RO1-AG18324 (to Dr. Kass), National Heart, Lung, and Blood Institute grant T32-HL07227 (to Dr. Borlaug), and a project grant from Omron Healthcare.
- Received March 7, 2007.
- Revision received July 16, 2007.
- Accepted July 23, 2007.
- American College of Cardiology Foundation