Abstract
BackgroundDecompensated 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.MethodsWe 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.ResultsThough 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.ConclusionPressure 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.
Highlights
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
Using a chronic canine model of LV dysfunction with either preserved or reduced ejection fraction induced by coronary microsphere embolization, we previously demonstrated that acute arterial pressure elevation results in marked elevation of LV filling pressures associated with prolonged relaxation and shortening of the diastolic filling period [3,4]
LV size and mass increased, LV ejection fraction declined, LV filling pressures increased, and tau was prolonged in both groups following the induction of LV dysfunction
Summary
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. Using a chronic canine model of LV dysfunction with either preserved or reduced ejection fraction induced by coronary microsphere embolization, we previously demonstrated that acute arterial pressure elevation results in marked elevation of LV filling pressures associated with prolonged relaxation and shortening of the diastolic filling period [3,4]. It is not entirely clear whether any differences in hemodynamics, LV volume or performance, or LV diastolic function can be demonstrated between canines with reduced or preserved LV ejection fraction in response to a stressor (e.g arterial pressure elevation). Little data has been generated using the coronary microsphere embolization model which produces a dilated, scarred left ventricle with reduced LV systolic function which has relevance to chronic coronary disease and LV dysfunction [7,8]
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