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PubMed2003

Value of the radiological study of the thorax for diagnosing left ventricular dysfunction in Chagas' disease.

OBJECTIVE: To determine the value of the radiological study of the thorax for diagnosing left ventricular dilation and left ventricular systolic dysfunction in patients with Chagas' disease. METHODS: A cross-sectional study of 166 consecutive patients with Chagas' disease and no other associated diseases. The patients underwent cardiac assessment with chest radiography and Doppler echocardiography. Sensitivity, specificity, and positive and negative predictive values of chest radiography were calculated to detect left ventricular dysfunction and the accuracy of the cardiothoracic ratio in the diagnosis of left ventricular dysfunction with the area below the ROC curve. The cardiothoracic ratio was correlated with the left ventricular ejection fraction and the left ventricular diastolic diameter. RESULTS: The abnormal chest radiogram had a sensitivity of 50%, specificity of 80.5%, and positive and negative predictive values of 51.2% and 79.8%, respectively, in the diagnosis of left ventricular dysfunction. The cardiothoracic ratio showed a weak correlation with left ventricular ejection fraction (r=-0.23) and left ventricular diastolic diameter (r=0.30). The area calculated under the ROC curve was 0.734. CONCLUSION: The radiological study of the thorax is not an accurate indicator of left ventricular dysfunction; its use as a screening method to initially approach the patient with Chagas' disease should be reevaluated.

Adult↗
PubMed2004

Patients with a hypertensive response to exercise have impaired systolic function without diastolic dysfunction or left ventricular hypertrophy.

OBJECTIVES: We sought to determine if a hypertensive response to exercise (HRE) is associated with myocardial changes consistent with early hypertensive heart disease. BACKGROUND: An HRE predicts the development of chronic hypertension (HT) and may reflect a preclinical stage of HT. METHODS: Patients with a normal left ventricular (LV) ejection fraction and a negative stress test were recruited into three matched groups: 41 patients (age 56 +/- 10 years) with HRE (>210/105 mm Hg in men; >190/105 in women), comprising 22 patients with (HT+) and 19 without resting hypertension (HT-); and 17 matched control subjects without HRE. Long-axis function was determined by measurement of the strain rate (SR), peak systolic strain, and cyclic variation (CV) of integrated backscatter in three apical views. RESULTS: An HRE was not associated with significant differences in LV mass index. Exercise performance and diastolic function were reduced in HRE(HT+) patients, but similar in HRE(HT-) patients and controls. Systolic dysfunction (peak systolic strain, SR, and CV) was significantly reduced in HRE patients (p < 0.001 for all). These reductions were equally apparent in patients with and without a history of resting HT (p = NS) and were independent of LV mass index and blood pressure (p < 0.01). CONCLUSIONS: An HRE is associated with subtle systolic dysfunction, even in the absence of resting HT. These changes occur before the development of LV hypertrophy or detectable diastolic dysfunction and likely represent early hypertensive heart disease.

Exercise↗
PubMed2004

QRS dispersion: an electrocardiographic index of systolic left ventricular dysfunction in patients with left bundle branch block.

The presence of complete left bundle branch block (LBBB) in patients with congestive heart failure has been proposed to be a factor that negatively affects left ventricular (LV) systolic function. The aim of this study was to evaluate the relative predictive value of QRS dispersion (QRSD) and QRS duration (QRSd) in relation to systolic performance of the left ventricle. The ejection fraction of 130 consecutive patients with LBBB was evaluated by standard echocardiographic methods, whereas QRSd and QRSD were measured. It was demonstrated that QRSD in patients with complete LBBB is strongly related to LV contractility. We, therefore, suggest that this simple electrocardiographic index may serve as a useful screening test for detection of patients with LV systolic dysfunction.

Adult↗
PubMed1983

Comparison of early systolic and early diastolic regional function during regional ischemia in a chronically instrumented canine model.

Depressed left ventricular function during the early part (first third) of both systole and diastole in the resting state have been reported to be sensitive indicators of coronary artery disease in patients with normal global function at rest. To evaluate the possible mechanisms of these findings, 11 dogs were chronically instrumented with segmental function sonomicrometers in the left circumflex and left anterior descending coronary artery distribution, circumflex coronary flow probes and cuff occluders, aortic flow probes and ventricular pressure transducers. Percent segmental function during the first third of systole and diastole was measured in the control state and with graded circumflex artery flow reductions. Significant decreases in early systolic function with ischemia in the circumflex artery distribution were partially offset by compensatory augmented shortening in the left anterior descending artery distribution. With ischemia in the circumflex distribution, there was prolonged contraction into diastole manifested as impaired relaxation. Simultaneously, in the left anterior descending artery distribution, there was minimal compensatory enhanced relaxation. These results suggest that early systolic dysfunction in ischemic segments may be offset by enhanced function in nonischemic segments, rendering minimal, if any, change in global systolic function. Early diastolic dysfunction in ischemic segments exceeds compensatory changes in nonischemic areas by two-to-four-fold. Hence, early diastolic functional indexes may be more sensitive indicators of ischemia at rest than early systolic functional indexes.

Animals↗
PubMed1997

Patients with mild heart failure worsen during withdrawal from digoxin therapy.

OBJECTIVES: We investigated whether patients with mild heart failure due to left ventricular systolic dysfunction were at risk of worsening during digoxin withdrawal. BACKGROUND: Deterioration during digoxin withdrawal is often believed to be restricted to patients with moderate to severe clinical evidence of heart failure. To test this hypothesis, we studied the outcome of patients categorized by treatment assignment and a clinical signs and symptoms heart failure score in two rigorously designed clinical heart failure trials: the Prospective Randomized Study of Ventricular Function and Efficacy of Digoxin (PROVED) and the Randomized Assessment of Digoxin and Inhibitors of Angiotensin-Converting Enzyme (RADIANCE) trial. METHODS: Potential differences in treatment failure, left ventricular ejection fraction and exercise capacity were evaluated in three groups of patients: those with mild heart failure (score < or = 2) who were withdrawn from digoxin (Dig WD Mild); those with moderate heart failure (score > 2) who were withdrawn from digoxin (Dig WD Moderate); and patients who continued receiving digoxin regardless of heart failure score (Dig Cont). RESULTS: Heart failure score at randomization did not predict outcome during follow-up in Dig Cont-group patients. Dig WD Mild-group patients were at increased risk of treatment failure and had deterioration of exercise capacity and left ventricular ejection fraction compared with that in Dig Cont-group patients (all p < 0.01). Patients in the Dig WD Moderate group were significantly more likely to experience treatment failure than patients in either the Dig WD Mild or Dig Cont group (both p < 0.05). CONCLUSIONS: Patients with systolic left ventricular dysfunction were at risk of clinical deterioration after digoxin withdrawal despite mild clinical evidence of congestive heart failure.

Aged↗
PubMed1993

Regional remodeling and nonuniform changes in diastolic function in patients with left ventricular dysfunction: modification by long-term enalapril treatment. The SOLVD Investigators.

OBJECTIVES: The purpose of the present study was to assess the process of late regional remodeling and the changes in regional diastolic function at the base and apex of the left ventricle in patients with chronic systolic dysfunction. BACKGROUND: Remodeling has been suggested to play an important role in the progression of left ventricular dysfunction and heart failure. However, the regional difference in the process of late remodeling and its relation to diastolic function remain unclear. METHODS: In 32 patients with previous myocardial infarction and left ventricular ejection fraction < or = 35%, left ventricular hemodynamic and angiographic data were studied before and 1 year after randomization to conventional therapy with placebo (n = 12) or enalapril, 10 mg twice daily (n = 20). Left ventricular regional wall dynamics were analyzed in the basal and apical regions by the area method. RESULTS: In the placebo group, left ventricular end-diastolic and end-systolic regional areas increased significantly over time at the base but were unchanged at the apex. At the base, the diastolic left ventricular pressure-regional area relation shifted rightward and the regional stiffness constant decreased (6.9 +/- 4.3 to 5.0 +/- 3.1 x 10(-3) mm-2, p < 0.05), indicating an increase in regional distensibility. At the apex, however, the diastolic pressure-regional area relation shifted upward slightly, and the regional stiffness constant increased from 11.5 +/- 4.4 to 14.4 +/- 5.6 x 10(-3) mm-2 (p = 0.08). The regional peak filling rate was maintained at the base but decreased at the apex (1,014 +/- 436 to 762 +/- 306 mm2/s, p < 0.05); further, the changes in regional peak filling rate during follow-up were inversely related to the changes in the regional stiffness constant (r = -0.78, p < 0.001) at the apex. In contrast, in the enalapril group, end-diastolic and end-systolic regional areas significantly decreased over time both at the base and at the apex. Diastolic pressure-regional area relations shifted leftward, but the regional stiffness constant and regional peak filling rate did not change significantly either at the base or at the apex. CONCLUSIONS: These findings suggest that in patients with severe systolic left ventricular dysfunction, there was a regional difference in the process of late remodeling between the base and apex of the left ventricle, which was associated with nonuniform changes in regional diastolic function in the placebo group. The data also suggest that the nonuniform progression of regional remodeling and diastolic dysfunction was prevented by long-term enalapril treatment.

Cardiac Catheterization↗
PubMed2001

Left ventricular dysfunction, natriuretic peptides, and mortality in an urban population.

OBJECTIVE: To report the mortality of left ventricular systolic dysfunction (LVD), assessed objectively by echocardiography, and its association with natriuretic peptide hormones in a random sample of 1640 men and women aged 25-74 years from a geographical, urban population. METHODS: Left ventricular function was measured by echocardiography in 1640 attendees studied in 1992-3. LVD was defined as a left ventricular ejection fraction (LVEF) </= 30%. Plasma concentrations of N-terminal atrial natriuretic peptide (N-ANP) and brain natriuretic peptide (BNP) were measured by standard radioimmunoassays. Mortality was documented at four years. RESULTS: The four year all cause mortality rate in the whole cohort was 4.9% (80 deaths). It was 21% (nine deaths) in those with an LVEF </= 30% and 4% in those whose LVEF was > 30% (p < 0.001). The median (interquartile range) BNP concentration in those who died was 16.9 pg/ml (8.8-27) and 7.8 pg/ml (3.4-13) in survivors (p < 0.0001). Similarly, N-ANP had a median concentration of 2.35 ng/ml (1.32-3.36) in those with a fatal outcome and 1.27 ng/ml (0.9-2.0) in those alive at four years (p < 0.0001). Subjects with an LVEF </= 40% also had a significant mortality rate of 17% if they also had a BNP concentration >/= 17.9 pg/ml compared with 6.8% if their BNP was below this concentration (p = 0.013). Multivariate analysis revealed the independent predictors of four year all cause mortality to be increasing age (p < 0.001), a BNP concentration >/= 17.9 pg/ml (p = 0.006), the presence of ischaemic heart disease (p = 0.03), and male sex (p = 0.04). CONCLUSIONS: LVD is associated with a considerable mortality rate in this population. BNP also independently predicts outcome. In addition to its role as a diagnostic aid in chronic heart failure and LVD, it provides prognostic information and clarifies the meaning of a given degree of LVD.

Adult↗
PubMed2001

Estimating pulmonary capillary wedge pressures using Doppler variables of early diastolic left ventricular inflow.

The present study was performed to determine whether a multilineal regression model based on the early diastolic transmitral flow peak velocity (E) and the propagation velocity of early diastolic inflow (PV) could estimate the pulmonary capillary wedge pressure (PCWP). PCWP and Doppler variables were simultaneously recorded in 30 patients. PCWP was estimated by multilinear regression analysis using E and PV. The predictive accuracy of the equation obtained from the analysis was tested prospectively in a separate group of 65 patients divided into 3 groups: left ventricular (LV) systolic dysfunction (Group A), LV hypertrophy (Group B), and preserved systolic function without hypertrophy (Group C). The initial results obtained in groups B and C, respectively, were: r=0.77; r=0.81. These results indicate that a multilinear regression model based on E and PV is a noninvasive method of accurately estimating PCWP in a variety of cardiac disease states.

Adult↗
PubMed2001

[Cardiac resynchronization therapy in terminal heart failure: current status and prospects].

BACKGROUND: With regard to epidemiological aspects, heart failure has been shown an increasing incidence in constrast to coronary artery disease which counts decreasingly due to secondary and primary prevention. The present data show an incidence for heart failure of 2% per year. 4-5 million people are newly affected by the disease. The prognosis is limited after diagnosis is confirmed. According to the US Framingham study, the median life expectancy is 3.2 and 5.4 after diagnosis for male and female, respectively. For patients in an advanced stage of the disease the mortality rate is 27% within 3 years. AV SEQUENTIAL PACING: The introduction of AV sequential pacing by the Austrian group of Margarete Hochleitner in 1992 showed an improved left ventricular systolic function, an improved clinical benefit in terms of NYHA classification, an enhanced left ventricular ejection fraction, an improved systolic and diastolic blood pressure, a reduction of the heart-chest relationship as well as a reduction of the resting hart rate and the echocardiographic dimension parameters. STUDIES: First experimental approach for biventricular stimulation, which means the simultaneous activation of the right and the left chamber, relied on the observation of a distorted ventricular activation due to the presence of a bundle branch block. The bundle branch block is a result of the dilatation of the myocardial fibers, death of myocardial cells which are replaced by fibrous tissue. Resynchronization of both ventricles was associated with an improved left ventricular function and improved diastolic relaxation. Clinical studies of patients with heart failure, severe left ventricular systolic dysfunction, and left bundle branch block have shown that systolic function can be improved by electrically stimulating the site of late activation. The magnitude of the improvement seems to be associated with the duration of the intrinsic surface QRS complex and whether the ventricle ipsilateral with the conduction defect is stimulated. The effect of ventricular resynchronization therapy was optimized by timing of atrioventricular activation associated with a decrease in both systolic and diastolic mitral regurgitation. CONCLUSION: The prognosis of patients with end-stage heart failure is limited by two determinants: myocardial pump failure and sudden (arrhythmogenic) cardiac death. Due to the fact that the incidence for sudden cardiac death is considerably high in patients with end-stage heart failure it is reasonable to include the implantation of cardioverters/defibrillaters (ICD) in the concept of biventricular stimulation.

Blood Pressure↗
PubMed1999

[Brain natriuretic peptide (BNP) in coronary insufficiency: relationship with left ventricular filling and exercise tolerance].

Brain natriuretic peptide (BNP) is a recently discovered peptide, secreted by the atria and ventricles in response to parietal distension. It was recently proposed as a screening test for left ventricular failure. The authors assayed this peptide at rest in 37 patients with chronic heart failure due to left ventricular systolic dysfunction and another 20 patients with various diseases (respiratory failure, cirrhosis, heart transplantation, "diastolic" heart failure) but normal left ventricular systolic function. A significant increase compared to normal values was observed not only in the group of heart failure patients, but also in patients with all other diseases. BNP was significantly higher in NYHA class IV patients. The relationship between plasma BNP levels and ejection fraction was not significant. On the other hand, a good correlation was observed between BNP and left ventricular filling parameters evaluated by cardiac Doppler: E wave deceleration time (r = -0.53, p = 0.001), E/A ratio: r = 0.57 p = 0.005) or VO2 max (r = -0.55, p < 0.005).

Aged↗
PubMed1993

[Hemodynamics in heart failure: systolic and diastolic dysfunction].

Cardiac insufficiency is hemodynamically characterised by reduced cardiac output and increased diastolic filling pressure at rest and/or during physical activity. The increase in diastolic filling pressure compensates cardiac output and is either a result of increased initial tension of muscle fibers (Frank-Starling's Law) or a sign of decreased myocardial compliance. Increased initial tension of muscle fibers is a sign of systolic insufficiency, whereas reduced ventricular compliance indicates a disorder of diastolic ventricular function. In systolic insufficiency (= systolic dysfunction) a decrease in the ventricular ejection fraction is important, as is an increase in filling pressure. In diastolic congestive heart failure (= diastolic dysfunction) a reduced ventricular compliance with normal stroke function is typical.

Diastole↗
PubMed2001

Heart Failure with Normal Ejection Fraction.

Heart failure with normal ejection fraction, also known as diastolic heart failure, is a major problem for patients and health-care providers and is a substantial expense to society. The main pathophysiologic processes involved are increased left ventricular stiffness and abnormal relaxation, with resulting impaired left ventricular filling. These processes typically displace the pressure-volume relationship in an upward direction, resulting in increased left ventricular end-diastolic, left atrial, and pulmonary capillary wedge pressures, leading to symptoms of pulmonary congestion. The most common clinical disorders leading to diastolic heart failure are 1) hypertension with concentric left ventricular hypertrophy, 2) coronary artery disease with decreased left ventricular compliance, 3) hypertrophic cardiomyopathy, and 4) aortic stenosis with concentric left ventricular hypertrophy. Echocardiography and cardiac catheterization with magnetic resonance imaging hold promise as future diagnostic tools. The approach to the treatment of diastolic heart failure is focused on four treatment goals: 1) persistent control of elevated blood pressure, with regression of left ventricular hypertrophy, 2) careful reduction of central blood volume (diuretics), 3) maintenance of atrial contraction and control of heart rate (beta-blockers, digoxin, atrioventricular pacing); and 4) improvement of left ventricular relaxation. There is currently no drug treatment specific for abnormal relaxation, although efforts are being made to develop such compounds. A promising future therapy includes agents that lyse advanced glycation end-products as an approach to relieving increased ventricular stiffness. In addition to pharmacotherapy, maintaining ideal body weight and a regular exercise program are also helpful in the treatment of diastolic heart failure. Although the overall prognosis of patients with diastolic dysfunction is more favorable than that of patients with systolic dysfunction, the frequency of treatment failure and recurrent symptoms underscores the need for further improvement in treatment of this condition.

Journal Article↗
PubMed1997

Comparison of alcoholic cardiomyopathy in women versus men.

To compare the prevalence and cardiac status of male and female alcoholics with alcoholic cardiomyopathy during a 5-year period, all chronic alcoholics with dilated cardiomyopathy who had clinical symptoms of heart failure were included. Alcoholic cardiomyopathy was diagnosed in 10 chronic alcoholic women and in 26 men; the prevalence of alcoholic cardiomyopathy was similar in both sexes. No significant differences were observed in age, nutritional parameters, and clinical and radiologic data of heart failure between the 2 groups. Alcoholic women reported a significantly lower daily dose of ethanol (p = 0.002), a shorter duration of alcoholism (p = 0.017), and a lower total lifetime dose of ethanol consumption (p = 0.001), and had a lower New York Heart Association functional class than men. Women also had lesser ventricular dysfunction than men. In a multivariate analysis, left ventricular systolic dysfunction was related to the total lifetime dose of ethanol consumption (p <0.04), but not to gender. Finally, when patients were matched for left ventricular ejection fraction, women had consumed a lower total lifetime dose of ethanol than men (p <0.001). The prevalence of alcoholic women with dilated cardiomyopathy was found to be similar to that of alcoholic men, although women required a lower total lifetime dose of ethanol to develop the disease.

Adult↗
PubMed1994

Exercise echocardiographic correlates of transient dilatation of the left ventricular cavity on exercise thallium-201 SPECT imaging.

Transient dilatation of the left ventricular cavity on exercise thallium perfusion imaging is recognized as a marker of significant coronary disease, but the mechanisms that produce this finding are not fully understood. We studied 32 patients who underwent exercise thallium imaging and exercise echocardiography to determine the changes in left ventricular cavity size that underlie transient dilatation. Left ventricular area from the apical four-chamber view was used to approximate left ventricular cavity size. There were 24 patients who did not have transient dilatation (group 1) and 8 patients who did have transient dilatation (group 2) on thallium imaging. Systolic area decreased from rest to exercise in group 1 patients but not in group 2 patients. There was no significant change in diastolic area from rest to exercise in either group 1 or group 2 patients. Thus, exercise-induced systolic dysfunction, manifested as a failure to decrease left ventricular systolic cavity size in exercise, may be an important mechanism in producing scintigraphic transient dilatation.

Echocardiography↗
PubMed2002

The role of B-type natriuretic peptide in the diagnosis of congestive heart failure in patients presenting to an emergency department with dyspnea.

OBJECTIVE: To determine the utility of B-type natriuretic peptide (BNP) in the diagnosis of congestive heart failure (CHF) in patients presenting with dyspnea to an emergency department (ED). METHODS: Seventy patients presenting with dyspnea to an ED from April to July 2001 were included in the study. Mean age was 72+/-16 years and 33 (47%) were male. BNP was measured in all patients at the moment of admission to the ED. Emergency-care physicians, blinded to BNP values, were required to assign a probable initial diagnosis. A cardiologist retrospectively reviewed the data (blinded to BNP measurements) and assigned a definite diagnosis, which was considered the gold standard for assessing the diagnostic performance of BNP. RESULTS: The mean BNP concentration was higher in patients with CHF (n=36) than in those with other diagnoses (990+/-550 vs 80+/-67 pg/mL, p<0.0001). Patients with systolic dysfunction had higher BNP levels than those with preserved systolic function (1,180+/-641 vs 753+/-437 pg/mL, p=0.03). At a blood concentration of 200 pg/mL, BNP showed a sensitivity of 100%, specificity of 97.1%, positive predictive value of 97.3%, and negative predictive value of 100%. The application of BNP could have potentially corrected all 16 cases in which the diagnosis was missed by the emergency department physician. CONCLUSION: BNP measurement is a useful tool in the diagnosis of CHF in patients presenting to the ED with dyspnea.

Aged↗
PubMed2006

[Predictors of in-hospital lethality in patients with advanced heart failure].

OBJECTIVE: Describe the clinical characteristics and identify potential risk factors for in-hospital lethality in patients with decompensated heart failure admitted to an intensive care unit. METHODS: Decompensated heart failure patients consecutively admitted to an intensive care unit between June 2001 and December 2003 were selected and followed during hospitalization until discharge or death. Clinical characteristics at admission were recorded and evaluated as independent risk predictors for in-hospital mortality by multiple logistic regression analysis. RESULTS: A total of 299 patients (69+/-13 years of age and 54% men) were enrolled. Coronary artery disease was the main cause of heart failure in 49% of the cases. Diabetes mellitus and systemic arterial hypertension occurred in 37.5% and 78% of the patients, respectively. At admission, 22% of them had atrial fibrillation, 21.5% had renal dysfunction, and 48% anemia (16.5% with severe anemia). Severe systolic dysfunction (left ventricular ejection fraction <30%) affected 44% of the patients. In-hospital mortality was 17.4%. After the multivariate analysis had been performed, previous history of stroke, atrial fibrillation, renal failure, age > 70 years, and hyponatremia were independently associated with in-hospital mortality. CONCLUSION: Patients admitted to an intensive care unit due to decompensated heart failure have high in-hospital lethality. In this study, variables recorded at admission, such as previous stroke, atrial fibrillation, hyponatremia, renal failure, and age > 70 years were predictors of in-hospital lethality.

Aged↗
PubMed2006

[Short term simvastatin use in patients with heart failure of ischemic origin. Changes of blood lipids, markers of inflammation and left ventricular function].

AIM: To study changes of left ventricular function and some markers of inflammation during use of simvastatin in patients with ischemic systolic heart failure. METHODS: Statin naive patients (n=70) with coronary heart disease (CHD), NYHA class II-IV HF and LV ejection fraction (EF) 35% or less after 1 month of stabilization were randomized to simvastatin 40 mg/day (n=36) or no statin (n=34). Lipids, tumor necrosis factor alpha (TNF), and C-reactive protein (CRP) were measured and echocardiography carried out at baseline and in 4 months. In patients with sinus rhythm (n=48) left ventricular diastolic function was assessed by Doppler echo. Seven patients were not restudied and analysis included data from 32 (statin) and 31 (control) patients. RESULTS: Groups were similar except baseline CRP which was significantly higher in controls. In statin treated patients reduction of low density lipoprotein (LDL) cholesterol (CH) was 42%, triglyceride levels also significantly decreased. High density lipoprotein CH rose by 14.4 and 12.9% in statin and control groups, respectively. Despite lower initial level decrease of CRP was significant only in statin group. No significant changes of TNF occurred in either group. Left ventricular EF rose equally in statin treated (+5.7+/-4.7%) and untreated (+4.1+/-4.6%) patients (p=ns). Significant increase of peak atrial filling velocity (A) and decrease of E/A in statin group were difficult to interpret in the presence of systolic dysfunction. CONCLUSION: Short term simvastatin use in patients with systolic heart failure due to CHD caused lowering of LDLCH and CRP however this was not associated with changes of left ventricular EF different from those in control group.

Aged↗
PubMed1994

Loss of elastic recoil in postischemic myocardium induces rightward shift of the systolic pressure-volume relationship.

Ischemia-induced systolic dysfunction has been ascribed to changes in cellular excitation-contraction coupling and diastolic dysfunction because of disruption of the extracellular collagen matrix. Therefore, systolic and diastolic pressure-volume relationships and O2 consumption were determined before and after 5 min of global ischemia in isolated blood-perfused porcine hearts. The slope of the systolic pressure-volume relationship was 7.2 +/- 0.6 (SE) mmHg.ml-1.100 g-1 (n = 18) at baseline and did not change during reperfusion, but the systolic volume intercept shifted from 1.0 +/- 0.4 ml/100 g at baseline to 3.7 +/- 1.4, 4.1 +/- 1.1, and 4.2 +/- 0.9 ml/100 g at 15, 30, and 60 min of reperfusion, respectively (all P < 0.05). The diastolic volume intercept was 8.2 +/- 0.7 ml/100 g at baseline and remained unchanged during reperfusion. Therefore, the difference of the systolic-diastolic volume intercepts, an index of elastic recoil forces, was decreased to 57 +/- 8, 49 +/- 7, and 47 +/- 9% of baseline values (P < 0.05). The shift of the systolic pressure-volume relationship was accompanied by a transient decrease of contractile efficiency (slope of O2 consumption-pressure-volume-area relationship) at 15 min of reperfusion (from 43 +/- 6 to 27 +/- 7%). We hypothesize that the rightward shift of the systolic pressure-volume relationship was compatible with a decrease of elastic-restoring forces, probably induced by alterations in the extracellular collagen matrix and/or the cytoskeleton, and thereby our data imply that left ventricular dysfunction of postischemic myocardium does not result solely from disturbances in excitation-contraction coupling.

Animals↗