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Comparison of the effect of pressure loading on left ventricular size, systolic and diastolic function in canines with left ventricular dysfunction with preserved and reduced ejection fraction.

Lavine SJ, Conetta DA - Cardiovasc Ultrasound (2008)

Bottom Line: With methoxamine, there were similar increases in LV size, LV pressures, and index of myocardial performance with the ejection fraction reduced similarly.A similar extent of isovolumic contraction and relaxation times and index of myocardial performance prolongation occurred with pressure loading.Pressure loading in a canine model of LV dysfunction with PreEF and RedEF resulted in similar degrees of LV dilatation, increased filling pressures, and increased index of myocardial performance.

View Article: PubMed Central - HTML - PubMed

Affiliation: Wayne State University, Detroit, MI 48202, USA. steven.lvine@jax.ufl.edu

ABSTRACT

Background: Decompensated heart failure may present with severe hypertension in patients with preserved (PreEF) or reduced left ventricular (LV) ejection fraction (RedEF) and is clinically indistinguishable. Previously, we demonstrated that arterial pressure elevation increases LV filling pressures in a canine model of chronic LV dysfunction with PreEF or RedEF. It is not clear whether any differences in hemodynamics, LV volume or performance, or diastolic function can be demonstrated between canines with PreEF or RedEF in response to arterial pressure elevation. We hypothesized that the LV systolic, diastolic, and hemodynamic response to pressure loading would be similar in RedEF or PreEF.

Methods: We studied 25 dogs with chronic LV dysfunction due to coronary microsphere embolization with RedEF (35 +/- 4%) and 20 dogs with PreEF (50 +/- 3%). Arterial pressure was increased with methoxamine infusion and hemodynamics and echo-Doppler parameters of LV size, function, transaortic and transmitral pulsed Doppler prior to and with methoxamine infusion was obtained.

Results: Though LV filling pressures were similar at baseline, LV size was larger (p < 0.01) and ejection fraction lower in dogs with RedEF (p < 0.001). With methoxamine, there were similar increases in LV size, LV pressures, and index of myocardial performance with the ejection fraction reduced similarly. Diastolic parameters demonstrated similar tau increases, E/A reduction, and diastolic filling shortening in RedEF and PreEF dogs. A similar extent of isovolumic contraction and relaxation times and index of myocardial performance prolongation occurred with pressure loading.

Conclusion: Pressure loading in a canine model of LV dysfunction with PreEF and RedEF resulted in similar degrees of LV dilatation, increased filling pressures, and increased index of myocardial performance.

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Isovolumic contraction time at baseline LV dysfunction (LVDys) and following pressure loading in dogs with LV dysfunction and preserved ejection fraction (left upper) and LV dysfunction with reduced ejection fraction (right upper) demonstrates similar extent of increases with pressure loading. Similarly, the isovolumic relaxation period at baseline LV dysfunction (LVDys) and following pressure loading in dogs with LV dysfunction and preserved ejection fraction (left lower) and LV dysfunction with reduced ejection fraction (right lower) demonstrates a similar degree of lengthening with pressure loading.
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Figure 3: Isovolumic contraction time at baseline LV dysfunction (LVDys) and following pressure loading in dogs with LV dysfunction and preserved ejection fraction (left upper) and LV dysfunction with reduced ejection fraction (right upper) demonstrates similar extent of increases with pressure loading. Similarly, the isovolumic relaxation period at baseline LV dysfunction (LVDys) and following pressure loading in dogs with LV dysfunction and preserved ejection fraction (left lower) and LV dysfunction with reduced ejection fraction (right lower) demonstrates a similar degree of lengthening with pressure loading.

Mentions: Table 2 1summarizes the results of arterial pressure incrementation with methoxamine in both groups. LV volumes increased with a reduction of LV ejection fraction in both groups. Stroke volume declined only in the RedEF group. LVEDP and LV minimal pressures, effective arterial elastance and chamber stiffness increased in both groups. Effective arterial elastance was lower in the RedEF group at baseline LV dysfunction (p < 0.05) and with pressure loading (p < 0.05) than in the PreEF group. Figure 1 displays composite LV pressure-volume plots (with mean ± standard error of the mean) prior to and following methoxamine infusions for PreEF (left) and RedEF (right) groups. Both groups demonstrate a similar rightward and upper shift of the pressure-volume curve from the baseline LV dysfunction plot. LV volumes (p < 0.01) were greater and LV ejection fraction (p < 0.001) were further reduced in the RedEF group than the PreEF group with arterial pressure elevation. Table 3 1summarizes the results of arterial pressure elevation in both groups with regard to diastolic filling parameters, IMP and its components. For both groups, E and E/A declined, the time to onset of mitral velocity was delayed, and was associated with shortening of diastolic filling, prolongation of IRT and ICT with marked increases in IMP. The IMP value with pressure loading was significantly more elevated in the RedEF group. Figure 2 and 3 summarizes the individual canine response in each group to pressure loading with regard to IMP and diastolic filling period (figure 2) and IRT and ICT (figure 3). The responses of each of these parameters to pressure loading were similar in both groups of dogs. Mitral regurgitation was noted in 5 dogs with PreEF with methoxamine infusion (mild in all; jet area/left atrial area = 6%, 6%, 8%, 10%, and 11%) and 8 dogs with ReEF (mild in all; 6%, 7%, 9%, 11%, 12%, 14%, 15% and 17%)


Comparison of the effect of pressure loading on left ventricular size, systolic and diastolic function in canines with left ventricular dysfunction with preserved and reduced ejection fraction.

Lavine SJ, Conetta DA - Cardiovasc Ultrasound (2008)

Isovolumic contraction time at baseline LV dysfunction (LVDys) and following pressure loading in dogs with LV dysfunction and preserved ejection fraction (left upper) and LV dysfunction with reduced ejection fraction (right upper) demonstrates similar extent of increases with pressure loading. Similarly, the isovolumic relaxation period at baseline LV dysfunction (LVDys) and following pressure loading in dogs with LV dysfunction and preserved ejection fraction (left lower) and LV dysfunction with reduced ejection fraction (right lower) demonstrates a similar degree of lengthening with pressure loading.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2626582&req=5

Figure 3: Isovolumic contraction time at baseline LV dysfunction (LVDys) and following pressure loading in dogs with LV dysfunction and preserved ejection fraction (left upper) and LV dysfunction with reduced ejection fraction (right upper) demonstrates similar extent of increases with pressure loading. Similarly, the isovolumic relaxation period at baseline LV dysfunction (LVDys) and following pressure loading in dogs with LV dysfunction and preserved ejection fraction (left lower) and LV dysfunction with reduced ejection fraction (right lower) demonstrates a similar degree of lengthening with pressure loading.
Mentions: Table 2 1summarizes the results of arterial pressure incrementation with methoxamine in both groups. LV volumes increased with a reduction of LV ejection fraction in both groups. Stroke volume declined only in the RedEF group. LVEDP and LV minimal pressures, effective arterial elastance and chamber stiffness increased in both groups. Effective arterial elastance was lower in the RedEF group at baseline LV dysfunction (p < 0.05) and with pressure loading (p < 0.05) than in the PreEF group. Figure 1 displays composite LV pressure-volume plots (with mean ± standard error of the mean) prior to and following methoxamine infusions for PreEF (left) and RedEF (right) groups. Both groups demonstrate a similar rightward and upper shift of the pressure-volume curve from the baseline LV dysfunction plot. LV volumes (p < 0.01) were greater and LV ejection fraction (p < 0.001) were further reduced in the RedEF group than the PreEF group with arterial pressure elevation. Table 3 1summarizes the results of arterial pressure elevation in both groups with regard to diastolic filling parameters, IMP and its components. For both groups, E and E/A declined, the time to onset of mitral velocity was delayed, and was associated with shortening of diastolic filling, prolongation of IRT and ICT with marked increases in IMP. The IMP value with pressure loading was significantly more elevated in the RedEF group. Figure 2 and 3 summarizes the individual canine response in each group to pressure loading with regard to IMP and diastolic filling period (figure 2) and IRT and ICT (figure 3). The responses of each of these parameters to pressure loading were similar in both groups of dogs. Mitral regurgitation was noted in 5 dogs with PreEF with methoxamine infusion (mild in all; jet area/left atrial area = 6%, 6%, 8%, 10%, and 11%) and 8 dogs with ReEF (mild in all; 6%, 7%, 9%, 11%, 12%, 14%, 15% and 17%)

Bottom Line: With methoxamine, there were similar increases in LV size, LV pressures, and index of myocardial performance with the ejection fraction reduced similarly.A similar extent of isovolumic contraction and relaxation times and index of myocardial performance prolongation occurred with pressure loading.Pressure loading in a canine model of LV dysfunction with PreEF and RedEF resulted in similar degrees of LV dilatation, increased filling pressures, and increased index of myocardial performance.

View Article: PubMed Central - HTML - PubMed

Affiliation: Wayne State University, Detroit, MI 48202, USA. steven.lvine@jax.ufl.edu

ABSTRACT

Background: Decompensated heart failure may present with severe hypertension in patients with preserved (PreEF) or reduced left ventricular (LV) ejection fraction (RedEF) and is clinically indistinguishable. Previously, we demonstrated that arterial pressure elevation increases LV filling pressures in a canine model of chronic LV dysfunction with PreEF or RedEF. It is not clear whether any differences in hemodynamics, LV volume or performance, or diastolic function can be demonstrated between canines with PreEF or RedEF in response to arterial pressure elevation. We hypothesized that the LV systolic, diastolic, and hemodynamic response to pressure loading would be similar in RedEF or PreEF.

Methods: We studied 25 dogs with chronic LV dysfunction due to coronary microsphere embolization with RedEF (35 +/- 4%) and 20 dogs with PreEF (50 +/- 3%). Arterial pressure was increased with methoxamine infusion and hemodynamics and echo-Doppler parameters of LV size, function, transaortic and transmitral pulsed Doppler prior to and with methoxamine infusion was obtained.

Results: Though LV filling pressures were similar at baseline, LV size was larger (p < 0.01) and ejection fraction lower in dogs with RedEF (p < 0.001). With methoxamine, there were similar increases in LV size, LV pressures, and index of myocardial performance with the ejection fraction reduced similarly. Diastolic parameters demonstrated similar tau increases, E/A reduction, and diastolic filling shortening in RedEF and PreEF dogs. A similar extent of isovolumic contraction and relaxation times and index of myocardial performance prolongation occurred with pressure loading.

Conclusion: Pressure loading in a canine model of LV dysfunction with PreEF and RedEF resulted in similar degrees of LV dilatation, increased filling pressures, and increased index of myocardial performance.

Show MeSH
Related in: MedlinePlus