Original article
Impact of Preload and Afterload on Global and Regional Right Ventricular Function and Pressure: A Quantitative Echocardiography Study

https://doi.org/10.1016/j.echo.2005.12.021Get rights and content

Background

Several quantitative echocardiographic measures of global and regional right ventricular (RV) function have been proposed, but knowledge of the impact of increases in preload and afterload is limited.

Methods

Seventeen healthy participants were exposed to increased preload by rapid infusion of 30 mL/kg of saline over 15 minutes, and to increased afterload simulated in an 16- to 18-hour stay in a controlled hypoxic environment (fractional concentration of oxygen in inspired gas = 12.3%). Two-dimensional, Doppler, and Doppler tissue echocardiography evaluations were performed to evaluate global and regional RV function, with changes evaluated by paired analysis.

Results

Peak tricuspid regurgitation velocity increased in both conditions, whereas the RV end-diastolic diameter and acceleration time of the pulmonary forward flow only increased with increased preload and afterload, respectively. Estimates of RV function and contractility remained stable: no changes in the RV isovolumic acceleration (1.6 ± 0.6 vs 1.6 ± 0.4 and 1.3 ± 0.4 cm/s2) or tricuspid annular plane systolic excursion (2.5 ± 0.4 vs 2.5 ± 0.3 and 2.6 ± 0.3 cm) were seen (baseline compared with increased afterload and preload, respectively). The RV index of myocardial performance was increased with increased afterload (0.26 ± 0.08 vs 0.34 ± 0.13, P < .05), whereas no changes with increased preload were seen. Changes in loading conditions did not affect the regional strain.

Conclusion

Moderate volume and pressure loading of the RV induces detectable changes in the RV pressure and morphology. Modern echocardiographic measures of systolic RV function seem stable with moderate increases in preload and afterload.

Section snippets

Methods

This study included 17 young healthy individuals with no history of cardiovascular or metabolic diseases, including hypertension or diabetes. Baseline electrocardiograms were normal and all participants were in sinus rhythm. The institutional review board approved the protocol and all participants signed informed consent before enrollment in the study.

Two-dimensional, Doppler, and Doppler tissue echocardiographic evaluations were performed at baseline, after hypoxic induced pulmonary

Results

The 17 participants included were 31 ± 9 years of age and 13 (76%) were male. They had mean body mass index of 24 ± 3 kg/m2 and a blood pressure of 115 ± 13/79 ± 9 mm Hg. They were in average physical condition, with maximal oxygen consumption per unit time of 36 ± 6 mL/kg equaling 98 ± 7% of the expected value for age and sex. On echocardiography LV ejection fraction was 61 ± 4%. The baseline echocardiographic measures of RV size and estimates of function and diastolic and systolic pressures

Discussion

This study is the first to examine the impact of changes in loading conditions on newer quantitative echocardiographic methods on RV function in human beings. The study confirms previous findings of load independence of IVA as a measure of RV contractility. The findings also suggest that PA acceleration time may be a helpful adjunct in the determination of the hemodynamic mechanism of increased pulmonary pressure.

The models used for the manipulation of the loading conditions of the RV were

References (36)

  • G.R. Sutherland et al.

    Strain and strain rate imaging: a new clinical approach to quantifying regional myocardial function

    J Am Soc Echocardiogr

    (2004)
  • M.V. McConnell et al.

    Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism

    Am J Cardiol

    (1996)
  • M. Miniati et al.

    Value of transthoracic echocardiography in the diagnosis of pulmonary embolism: results of a prospective study in unselected patients

    Am J Med

    (2001)
  • D. Kosturakis et al.

    Doppler echocardiographic prediction of pulmonary arterial hypertension in congenital heart disease

    Am J Cardiol

    (1984)
  • B. Marchandise et al.

    Noninvasive prediction of pulmonary hypertension in chronic obstructive pulmonary disease by Doppler echocardiography

    Chest

    (1987)
  • J. Meluzin et al.

    Pulsed Doppler tissue imaging of the velocity of tricuspid annular systolic motion; a new, rapid, and non-invasive method of evaluating right ventricular systolic function

    Eur Heart J

    (2001)
  • M. Vogel et al.

    Validation of myocardial acceleration during isovolumic contraction as a novel noninvasive index of right ventricular contractility: comparison with ventricular pressure-volume relations in an animal model

    Circulation

    (2002)
  • M. Vogel et al.

    Noninvasive assessment of left ventricular force-frequency relationships using tissue Doppler-derived isovolumic acceleration: validation in an animal model

    Circulation

    (2003)
  • Cited by (0)

    Supported by National Institutes of Health grant HL71478; American Heart Association grants 56051Z and 0525727Z; US Public Health Service grant M01-RR00585; and Danish Heart Foundation research fellowship grant 04-10-B109-A166-22192 (Dr Kjaergaard).

    View full text