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ABSTRACT: With left ventricular (LV) dysfunction, it is not clear how alterations in external constraint influence the index of myocardial performance (IMP). We have previously demonstrated that pericardial constraint is a factor in the production of the restrictive filling pattern. We hypothesized that altering pericardial constraint by changing intracardiac volume or removing the pericardium would produce similar directional changes in LV ejection time (LVET) and isovolumic relaxation time (IRT) resulting in minimal IMP changes.
We studied 13 canines with chronic moderate LV dysfunction. LV pressures, transmitral and transaortic Doppler were obtained prior to and following pericardiectomy (PECT) with alterations of intracardiac volume, using inferior vena caval occlusion (IVCO) and volume loading.
With an intact pericardium, IVCO reduced LV size, LV end diastolic pressure (LVEDP), and increased deceleration time (all P < 0.05) but did not affect IMP. Volume loading increased LV size, LVEDP, and shortened deceleration time (all P < 0.05). LVET and IRT lengthened (P < 0.05), and IMP declined (0.58 +/- 0.24 to 0.52 +/- 0.13, P < 0.05). Following PECT, IVCO reduced LV volumes and LVEDP (P < 0.05), but did not change IMP. Volume loading increased LV size, stroke volume, and LVEDP (all P < 0.05). IMP declined (0.57 +/- 0.13 vs 0.51 +/- 0.14, P < 0.05) due to an increase in both LVET and IRT (P < 0.05). Comparison of stages prior to and following PECT revealed an increased LVET and stroke volume (P < 0.05) but a similar IMP.
Increases in intracardiac volume associated with elevated LVEDP resulted in reduced IMPs. Pericardiectomy increases LV volumes, stroke volume, and LVET but did not influence IMP.
Echocardiography 09/2007; 24(7):712-22. · 1.24 Impact Factor
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ABSTRACT: Decompensated heart failure with preserved left ventricular (LV) ejection fraction (EF) is often accompanied by hypertensive episodes. We hypothesized that acute increase in arterial pressure results in elevated early and late diastolic LV pressures as a result of further impaired LV relaxation.
To test this hypothesis, we used a chronic canine model of LV systolic dysfunction with preserved LV function (LVDPEF) (EF > 50%) and elevated LV end-diastolic pressure using coronary microsphere embolization. At baseline and with LVDPEF, each dog was paced 10 beats above their baseline heart rate and high-fidelity LV pressures, echocardiographic LV volumes, and transmitral Doppler were obtained before and after methoxamine pressure loading.
With normal LV function, LV pressures at peak negative dP/dt (+18 mm Hg, P < .05) and at LV pressure minimum (+3.6 mm Hg, P < .01) increased. Both tau (P < .05) and LV end-diastolic pressure increased (5 +/- 3 vs 13 +/- 4 mm Hg, P < .01). EF was unchanged, although LV end-diastolic volume increased (P < .01). Pressure loading with LVDPEF resulted in a timing delay (P < .05) and a greater increase in LV pressures at peak negative dP/dt (+45 mm Hg) and LV minimal pressure (+7.5 mm Hg) as compared with normal LV function (P < .01). LV end-diastolic pressure increased (9 +/- 2-23 +/- 5 mm Hg, P < .001), diastolic filling period shortened (288 +/- 51-204 +/- 54 milliseconds, P < .01), and tau increased (P < .001). EF declined from 54 +/- 9% to 43 +/- 9% (P < .05) and LV size increased (P < .01).
Pressure loading with normal LV function and with LVDPEF results in increased LV diastolic pressures, which are further exaggerated with LVDPEF as a result of prolonged relaxation and shortened diastolic filling.
Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 12/2006; 19(11):1350-8. · 2.98 Impact Factor
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ABSTRACT: The index of myocardial performance (IMP) is a global cardiac function index with prognostic utility in patients with myocardial infarction and dilated cardiomyopathy but is preload dependent. We hypothesized that a volume overload lesion prolonging LV ejection time (LVET) may reduce IMP despite LV dysfunction (LVD).
The study groups consisted of 35 normals, 26 with LV dysfunction, and 60 with aortic regurgitation (AR): 40 with ejection fraction (EF) >50% (AR+Normal EF) and 20 with ejection fraction > or = 50% (AR+Reduced EF). We evaluated consecutive patients in each group with technically adequate 2D and Doppler echocardiography.
When compared to normal subjects (0.357+/-0.122), IMP was increased with LVD (0.604+/-0.278 p<0.001) but was similar in AR+Normal EF patients due to isovolumic relaxation time (IRT) and LVET prolongation. The IMP was lower in AR+Reduced EF group (0.346+/-0.172, p<0.001) as compared to the LVD group due to a prolonged LVET and a reduced IRT and isovolumic contraction time (ICT).
The IMP in AR+Normal EF patients was similar to normals due to IRT and LVET prolongation. The IMP was reduced in AR+Reduced EF patients compared to LVD patients due to IRT and ICT shortening and LVET prolongation. The index of myocardial performance in AR patients should be applied with caution.
Anadolu kardiyoloji dergisi: AKD = the Anatolian journal of cardiology 07/2006; 6(2):115-20. · 0.44 Impact Factor
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Steven J Lavine
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ABSTRACT: The index of myocardial performance has prognostic power in patients with cardiomyopathy and following myocardial infarction. As the index of myocardial performance has been shown to be preload and afterload dependent, the effect of altering contractility on IMP and its components with left ventricular dysfunction has been incompletely delineated.
Chronic left ventricular dysfunction was induced in 10 canines using coronary microsphere embolization. Each dog was instrumented and imaged with 2D echo and Doppler. At the same atrially paced rate, contractility was increased with a dobutamine infusion and then following 4 weeks of oral digoxin.
With chronic left ventricular dysfunction, a reduced left ventricular ejection fraction (42 +/- 3%, p < 0.001) and increased index of myocardial performance (0.58 +/- 0.17, p < 0.01) due to isovolumic contraction time lengthening and shortened left ventricular ejection time were noted. Dobutamine increased ejection fraction (p < 0.001), reduced left ventricular end diastolic pressure (p < 0.01), and reduced the index of myocardial performance (0.33 +/- 0.17, p < 0.001) due to isovolumic contraction time, isovolumic relaxation time, and left ventricular ejection time shortening. Digoxin increased ejection fraction (p < 0.05), reduced left ventricular end diastolic pressure (p < 0.05), and reduced the index of myocardial performance (0.42 +/- 0.13, p < 0.01) due to isovolumic contraction time shortening (p < 0.001). Both dobutamine and digoxin lengthened the diastolic filling period (p < 0.01).
Increased inotropy with digoxin and dobutamine reduced the index of myocardial performance in dogs with left ventricular dysfunction. Shortened isovolumic contraction time, increased diastolic filling period, and reduced left ventricular end diastolic pressure with digoxin may provide insight into its efficacy in heart failure.
Cardiovascular Ultrasound 01/2006; 4:45. · 1.26 Impact Factor
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Steven J Lavine
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ABSTRACT: The index of myocardial performance (IMP) has been used as a prognostic systolic-diastolic index for patients with dilated cardiomyopathy and postmyocardial infarction. To date, systematic evaluation of afterload alteration (arterial pressure) on IMP has not been performed with normal or reduced left ventricular (LV) function.
We studied 15 mongrel dogs at baseline, after the induction of acute ischemic LV dysfunction, and with chronic LV dysfunction. Each dog was atrially paced, and the arterial pressure was reduced with nitroprusside (NTP) (>10 mm Hg) and increased with methoxamine (Methox) (>30 mm Hg) in random order. Hemodynamics and transmitral and transaortic pulsed Doppler were obtained.
With normal LV function, there were no changes in IMP with NTP. Methox reduced IMP (0.51 +/- 0.12-0.45 +/- 0.12, P < .05) as a result of a shortened isovolumic contraction time (ICT). With acute LV dysfunction, IMP declined with NTP (0.74 +/- 0.19-0.65 +/- 0.17, P < .01) because of a shortened ICT and isovolumic relaxation time. Methox prolonged IMP (0.73 +/- 0.16-0.83 +/- 0.21, P < .05). With chronic LV dysfunction, NTP resulted in a reduced IMP (0.75 +/- 0.27-0.57 +/- 0.27, P < .01) as a result of a reduced ICT and isovolumic relaxation time and a prolonged LV ejection time associated with an increased LV ejection fraction. Methox increased IMP (0.72 +/- 0.26-1.31 +/- 0.43, P < .001) because of an increased ICT and isovolumic relaxation time and a reduced LV ejection time associated with a reduced LV ejection fraction. Forward stepwise regression indicated that both LV systolic pressure ( P = .0006) and LV ejection fraction ( P = .0222) were independent predictors of IMP.
IMP is afterload dependent in the normal LV. IMP is afterload dependent with acute and chronic LV dysfunction by influencing the isovolumic indices and LV ejection time in opposite directions. Further systematic evaluation of IMP is needed if this index is to be useful as a prognostic indicator.
Journal of the American Society of Echocardiography 05/2005; 18(4):342-50. · 3.71 Impact Factor
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Steven J Lavine
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ABSTRACT: The index of myocardial performance (IMP) has been used as a prognostic systolic-diastolic index for patients with dilated cardiomyopathy and postmyocardial infarction. To date, systematic evaluation of the effect of heart rate and preload alteration on IMP has not been performed with normal or reduced left ventricular (LV) function.
We studied 14 mongrel dogs at baseline, after the induction of acute ischemic LV dysfunction, and with chronic LV dysfunction. Heart rate was altered by atrial pacing 10 and 20 beats above baseline, and volume loading was accomplished with 10 mL/kg of saline at a paced rate. Hemodynamics, and transmitral and transaortic pulsed Doppler, were obtained.
With normal LV function, there were no changes in IMP with pacing. With acute LV dysfunction, IMP was also unchanged with pacing, although both LV ejection time (ET) (192 +/- 23 vs 208 +/- 25 milliseconds, P < .05) and isovolumic contraction time (58 +/- 25 vs 72 +/- 31 milliseconds, P < .05) declined. With chronic LV dysfunction, IMP was unchanged although LV ET declined (188 +/- 15 vs 204 +/- 18 milliseconds, P < .01). Volume loading did not alter the IMP with normal LV function although LV ET increased (208 +/- 25 vs 220 +/- 20 milliseconds, P < .001). With acute LV dysfunction, IMP decreased (0.66 +/- 0.11 vs 0.82 +/- 0.20, P < .05) because of a decrease in isovolumic relaxation time (63 +/- 33 vs 76 +/- 38 milliseconds, P < .05). With chronic LV dysfunction, IMP also declined with volume loading (0.59 +/- 0.29 vs 0.73 +/- 0.28, P < .01) because of an increase in LV ET (224 +/- 30 vs 198 +/- 22 milliseconds, P < .0001).
Heart rate incrementation does not change IMP. However, volume loading reduces IMP primarily as a result of LV ET lengthening with chronic LV dysfunction. Further systematic evaluation of IMP is needed if this index is to be useful as a prognostic indicator.
Journal of the American Society of Echocardiography 03/2005; 18(2):133-41. · 3.71 Impact Factor
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Steven J Lavine
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ABSTRACT: Restrictive filling pattern has been predictive of heart failure in patients with cardiomyopathy and after myocardial infarction, and is similar to the filling pattern in constrictive pericarditis and amyloid heart disease. The purpose of this study was to determine the role of both myocardial restraint and pericardial constraint in a chronic left ventricular dysfunction model with restrictive filling.
After instrumentation, a flat balloon containing a high-fidelity pressure catheter was inserted through a pericardial incision in 12 dogs with chronic left ventricular dysfunction. Intracardiac volume (ICV) was manipulated by inferior venal caval balloon occlusion and volume loading while hemodynamics, echo-assessed chamber size, and transmitral Doppler were obtained at the same atrial paced rate with an intact pericardium and after pericardiectomy.
With an intact pericardium, deceleration time increased with reduced ICV (130 +/- 35 vs 153 +/- 47 milliseconds, P <.05) and shortened with increased ICV (107 +/- 45 milliseconds, P <.05). The filling fraction at one-third of diastole decreased with reduced ICV (45.6 +/- 29.3 vs 24.2 +/- 15.8%, P <.01) and increased with increased ICV (60.1 +/- 14.8%, P <.05). Deceleration time could be predicted from intrapericardial pressure, the transmural left ventricular chamber stiffness constant, and filling fraction at one-third of diastole. After pericardiectomy, deceleration time also shortened with increased ICV (141 +/- 26 vs 112 +/- 38 milliseconds, P <.01). However, filling fraction at one-third of diastole was markedly reduced at paced baseline (19.9 +/- 14.4%, P <.01) and with increased ICV (15.5 +/- 11.8%, P <.001) as compared with an intact pericardium.
Pericardial constraint and myocardial restraint play a role in restrictive filling pattern. Pericardial constraint becomes evident with redistribution of diastolic filling to later in diastole after pericardiectomy.
Journal of the American Society of Echocardiography 02/2004; 17(2):152-60. · 3.71 Impact Factor
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Steven J Lavine
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ABSTRACT: Following an acute myocardial infarction (MI), the development of congestive heart failure (CHF) has been associated with a reduced ejection fraction (EF), pseudonormal or restrictive diastolic filling, and an increased index of myocardial performance (IMP).
To determine the comparative predictive value of EF, transmitral filling parameters, and IMP for the development of CHF following a first MI.
A retrospective analysis of consecutive echocardiographic and Doppler studies in patients admitted for their first acute MI from the years 1988 through 1992. We studied 109 patients following their first MI with two-dimensional and Doppler within 24 hours of MI. We divided patients into those who developed CHF within 15 days (43 patients) and without CHF (66 patients).
Patients who developed CHF had greater LV dilatation, lower EF (27.7%+/- 10.2% vs 45.6%+/- 13.2%, P < 0.001), higher E/A, shorter deceleration times (DCT; 157 +/- 69 msec vs 248 +/- 105 msec, P < 0.001), and increased IMP. Utilizing multiple logistic regression, EF (strongest predictor), DCT, and IMP were predictive of CHF. Nineteen patients in the no CHF group developed late CHF and had lower EFs (30.5%+/- 13.1% vs 50.5%+/- 9.8%, P < 0.001), higher E/A and shorter DCTs (161 +/- 39 msec vs 283 +/- 103 msec, P < 0.001). EF, DCT, and E/A were predictive of late CHF in patients without initial CHF. For patients admitted with a first MI, the EF, DCT, and to a lesser extent IMP predicted who would ultimately develop CHF. An EF < 40% or a DCT < 200 msec correctly predicted CHF in 60 of 62 patients.
We conclude that the early and ultimate development of CHF following a first MI were associated with an moderately reduced EF < 40%, pseudonormal diastolic filling indices, and an increased IMP.
Echocardiography 11/2003; 20(8):691-701. · 1.24 Impact Factor
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ABSTRACT: Ejection fraction (EF) is the most commonly used parameter of left ventricular (LV) systolic function and can be assessed by echocardiography. Quantitative echocardiography is time consuming and is as accurate as visual estimation, which has significant variability. We hypothesized that each echocardiographer has developed a mental set of guidelines that relate to how much individual segment shortening constitutes normal function or hypokinesis of varying extents. We determined the accuracy of applying these guidelines to an accepted technique of EF determination using a retrospective analysis of consecutive two-dimensional echocardiographic studies performed on patients who had radioventriculography (RVG) within 48 hours. Using a 12 segment model, we scored each segment at the base and mid-ventricular level based on segmental excursion and thickening. The apex was scored similarly but with 1/3 of the value based on a cylinder-cone model. EF was determined from the sum of segment scores and was estimated visually. We termed this approach visual quantitative estimation (VQE). We correlated the EF derived from VQE and visual estimation with RVG EF. In the training set, VQE demonstrated a strong correlation with RVG (r = 0.969), which was significantly greater than visual estimation (r = 0.896, P < 0.01). The limits of agreement for VQE (+12% to -7%) were similar to the limits of RVG agreement with contrast ventriculography (+10% to -11%) with similar intraobserver and interobserver variabilities. Similar correlation was noted in the prediction set between VQE and RVG EF (r = 0.967, P < 0.001). We conclude that VQE provides highly correlated estimates of EF with RVG.
Echocardiography 08/2003; 20(5):401-10. · 1.24 Impact Factor
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ABSTRACT: Patients with diabetes mellitus have an increased morbidity and mortality from cardiovascular disease. Both coronary artery disease and congestive heart failure (CHF) are largely responsible for the increased cardiovascular adverse events in patients with diabetes. This review discusses the pathophysiology of CHF, the mechanisms of left ventricular (LV) dysfunction and the neurohormonal mechanisms involved in both LV dysfunction and CHF. Diabetes with and without hypertension is an important cause of LV dysfunction and CHF. Diabetes may be responsible for the metabolic and ultrastructural causes of LV dysfunction, while hypertension may be responsible for the marked fibrotic changes that are found. Experimental induction of diabetes in animals has shed light on the biochemical and ultrastructural changes seen. The role of insulin to reverse both metabolic and structural changes is reviewed both from experimental data and with the limited amount of clinical data available. The therapy of CHF in patients with diabetes is similar to that of patients without diabetes, with therapy directed toward the use of beta-blockers and angiotensin converting enzyme (ACE) inhibitors. As the morbidity and mortality are higher in patients with diabetes, several studies have pointed out the importance of this subgroup where the opportunity to make a significant clinical impact exists. A significant opportunity exists to reduce morbidity and mortality with beta-blockers and ACE inhibitors when ischaemia and CHF are both present. However, studies in patients diabetes have been limited to post hoc subgroup analyses and rarely as predefined subgroups. Clinical trials involving patients with diabetes with and without hypertension and LV dysfunction are clearly needed in the future to adequately address the needs of this high risk subgroup.
Drugs 02/2002; 62(2):285-307. · 4.23 Impact Factor
