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Augmentation index, left ventricular contractility, and wave reflection

Citation

Sharman, JE and Davies, JE and Jenkins, C and Marwick, TH, Augmentation index, left ventricular contractility, and wave reflection, Hypertension, 54, (5) pp. 1099-1105. ISSN 0194-911X (2009) [Refereed Article]


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Copyright Statement

Copyright 2009 American Heart Association

DOI: doi:10.1161/HYPERTENSIONAHA.109.133066

Abstract

Augmentation index (AIx), a correlate of mortality, is thought to be influenced by left ventricular contractility and wave reflections. However, the relationship of AIx with left ventricular contractility changes has never been assessed, and the wave reflection theory has recently been questioned. This study sought to examine arterial waveform changes in response to reduced "wave reflection" and increased left ventricular contractility induced by dobutamine. Simultaneous radial tonometry (for AIx) and tissue Doppler echocardiography (for peak longitudinal systolic strain rate [SR] as an analogue of left ventricular contractility) were recorded at rest and peak dobutamine-induced stress in 50 patients (41 men; aged 62±10 years). From baseline to peak stress there was an increase in heart rate (70±11 to 127±17 bpm; P<0.001) and SR (-0.88±0.23 to 1.81±0.43 1/s; P<0.001), whereas AIx decreased (27±9% to 7±15%; P<0.001). There was also a greater increase in the systolic (compared with diastolic) pressure-time integral relative to cardiac cycle length (3.2±1.9 versus 1.8±1.1 mm Hg; P<0.001), indicating that wave reflection was not shifted into diastole as per the current belief. AIx was significantly associated with ejection duration (r=0.88), heart rate (r=-0.81), and SR (r=0.72; P<0.001 for all). However, when SR was heart rate corrected, there was no significant association with AIx (r=0.18; P=0.11). The strongest independent correlate of AIx was ejection duration, accounting for 78% variance (β0.88; model R2=0.77; P<0.001). Neither SR (β=0.12; P=0.18) nor heart rate–corrected SR (β=0.02; P=0.72) was associated with AIx. We conclude that AIx is determined by chronotropic rather than inotropic effects, as well as factors other than wave reflection.

Item Details

Item Type:Refereed Article
Research Division:Medical and Health Sciences
Research Group:Cardiorespiratory Medicine and Haematology
Research Field:Cardiology (incl. Cardiovascular Diseases)
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Cardiovascular System and Diseases
Author:Sharman, JE (Professor James Sharman)
Author:Marwick, TH (Professor Tom Marwick)
ID Code:63746
Year Published:2009
Web of Science® Times Cited:50
Deposited By:Menzies Institute for Medical Research
Deposited On:2010-05-26
Last Modified:2014-05-23
Downloads:0

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