Biomedical subjects

A Imparato

Publications and source records attributed to A Imparato.

At least 19 recordsLinked to original sources

PubMed2006

Fluctuation relations for a driven Brownian particle.

We consider a driven Brownian particle, subject to both conservative and nonconservative applied forces, whose probability evolves according to the Kramers equation. We derive a general fluctuation relation, expressing the ratio of the probability of a given Brownian path in phase space with that of the time-reversed path, in terms of the entropy flux to the heat reservoir. This fluctuation relation implies those of Seifert, Jarzynski, and Gallavotti-Cohen in different special cases.

Journal Article↗

PubMed2005

Work-probability distribution in systems driven out of equilibrium.

We derive the differential equation describing the time evolution of the work probability distribution function of a stochastic system which is driven out of equilibrium by the manipulation of a parameter. We consider both systems described by their microscopic state or by a collective variable which identifies a quasiequilibrium state. We show that the work probability distribution can be represented by a path integral, which is dominated by "classical" paths in the large system size limit. We compare these results with simulated manipulation of mean-field systems. We discuss the range of applicability of the Jarzynski equality for evaluating the system free energy using these out-of-equilibrium manipulations. Large fluctuations in the work and the shape of the work distribution tails are also discussed.

Journal Article↗

PubMed2003

Lateral and transverse diffusion in two-component bilayer membranes.

We study the lateral and transverse diffusion of amphiphiles in two-component bilayer membranes, using a coarse-grained model for amphiphilic molecules and combined Monte Carlo-Molecular Dynamics simulations. Membrane structural properties, such as the mean thickness, are also measured. The dependence of such properties on membrane composition, inter-molecular interactions, and amphiphile stiffness is determined. In particular, we show that addition of shorter amphiphiles drives the model membrane towards a more fluid state, with increased amphiphile lateral diffusion rates. These results can be understood in the framework of a simple free-volume model. Furthermore, we observe an increase in the trans-membrane diffusion when the interaction energy of amphiphiles with their neighboring molecules is decreased.

Biological Transport↗

PubMed2002

["Bad" sleepers... Causes, effects, and diagnosis of sleep-related breathing disorders in cardiac patients].

Cardiovascular and cerebrovascular disease are the most common life-threatening disease in the industrialized world. There is high interest in sleep apnea and cardiovascular disease: several studies have demonstrated an association between sleep apnea and cardiovascular and cerebrovascular events. The aim of this review is to critically appraise the possible adverse physiological consequences of sleep apnea on the cardiovascular system and to assess whether such adverse effects constitute a risk for the development of cardiovascular disease.

Heart Diseases↗

PubMed2001

Accurate noninvasive estimation of pulmonary vascular resistance by Doppler echocardiography in patients with chronic failure heart failure.

OBJECTIVES: This study was undertaken to explore further the relationship between Doppler-derived parameters of pulmonary flow and pulmonary vascular resistance (PVR) and to determine whether PVR could be accurately estimated noninvasively from Doppler flow velocity measurements in patients with chronic heart failure. BACKGROUND: The assessment of PVR is of great importance in the management of patients with heart failure. However, because of the inconclusive and conflicting data available, Doppler estimation of PVR is still considered unreliable. METHODS: Simultaneous Doppler echocardiographic examination and right heart catheterization were performed in 63 consecutive sinus rhythm heart failure patients with severe left ventricular systolic dysfunction. Hemodynamic PVR was calculated with the standard formula. The following Doppler variables on pulmonary flow and tricuspid regurgitation velocity curve were correlated with PVR: maximal systolic flow velocity, pre-ejection period (PEP), acceleration time (AcT), ejection time, total systolic time (TT), velocity time integral, and right atrium-ventricular gradient. RESULTS: At univariate analysis, all variables except maximal systolic flow velocity and velocity time integral showed a significant, although weak, correlation with PVR. The best correlation found was between AcT and PVR (r = -0.68). By regression analysis, only PEP, AcT and TT entered into the final equation, with a cumulative r = 0.87. When the function (PEP/AcT)/TT was correlated with PVR, the correlation coefficient further improved to 0.96. Of note, this function prospectively predicted PVR (r = 0.94) after effective unloading manipulations. CONCLUSIONS: The analysis of Doppler-derived pulmonary systolic flow is a reliable and accurate tool for estimating and monitoring PVR in patients with chronic heart failure due to left ventricular systolic dysfunction.

Blood Flow Velocity↗

PubMed1999

Estimation of pulmonary wedge pressure by transmitral Doppler in patients with chronic heart failure and atrial fibrillation.

Previous studies have demonstrated that left ventricular (LV) filling pressures can be estimated from transmitral Doppler recording in patients in sinus rhythm who have a broad spectrum of cardiac diseases. However, the correlation between pulmonary wedge pressure (PWP) and mitral Doppler profile has not yet been clearly defined in patients with atrial fibrillation, particularly in the presence of severe LV systolic dysfunction. The aim of this study was to evaluate the correlations between PWP and transmitral Doppler variables in patients with atrial fibrillation and chronic heart failure due to dilated cardiomyopathy. PWP and the mitral Doppler profile were simultaneously recorded in 35 consecutive heart failure patients (28 men, 7 women; mean age, 69 +/- 9 years) with severe LV dysfunction (mean ejection fraction 22% +/- 5%). Doppler measurements were averaged over 10 cardiac cycles. In addition, left atrial areas were derived from the apical 4-chamber view. Significant relations were observed between PWP and several parameters derived from the mitral flow: isovolumic relaxation time (r = -70), acceleration rate (r = 0.78), deceleration rate (r = 0.82), and deceleration time (r = -0.95). However, by stepwise multivariate analysis, deceleration time emerged as the sole independent predictor of PWP (r2 = 0.95, F = 590). The analysis led to the following equation: PWP = 51 - 0.26 (deceleration time). Our data suggest that mitral Doppler echocardiography is a useful tool for predicting PWP in heart failure patients with severe LV dysfunction even in the presence of atrial fibrillation.

Aged↗

PubMed1998

Doppler-derived acceleration rate of right ventricular early filling as a measurement of right atrial pressure in chronic heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

This study demonstrates that a Doppler-derived tricuspid flow velocity pattern provides an accurate, feasible, and noninvasive method of estimating and monitoring mean right atrial pressure in patients with heart failure due to left ventricular systolic dysfunction, and who are both in sinus rhythm and atrial fibrillation. In particular, the acceleration rate of early right ventricular filling is a powerful and independent predictor of mean right atrial pressure.

Cardiomyopathy, Dilated↗

PubMed1998

Reversible restrictive left ventricular diastolic filling with optimized oral therapy predicts a more favorable prognosis in patients with chronic heart failure.

OBJECTIVES: We sought to assess whether in clinically stable patients with chronic heart failure (CHF) the prolongation (i.e., increase) of an initially short (< or = 125 ms) Doppler transmitral deceleration time (DT) of early filling obtained with long-term optimal oral therapy predicts a more favorable prognosis. BACKGROUND: It has been recently demonstrated that transmitral early DT is a powerful independent predictor of poor prognosis in patients with left ventricular dysfunction. However, DT may change over time according to loading conditions and medical treatment. METHOD: One hundred forty-four patients with CHF and a short DT (< or = 125 ms) underwent repeat Doppler echocardiographic study 6 months after the initial examination, while clinically stable with optimal oral therapy, and were then followed up for a mean period of 26 +/- 7 months. RESULTS: After 6 months, DT had not changed in 80 patients (group 1), whereas it was significantly prolonged (> 125 ms) in the remaining 64 patients (group 2). Baseline Doppler echocardiographic features were similar in the two groups. No changes were found after 6 months in group 1, whereas group 2 showed a slight but significant (p < 0.01) reduction in end-systolic volume, an improvement in left ventricular ejection fraction (p < 0.01) and a decrease (p < 0.01) in the degree of tricuspid regurgitation. During follow-up, 37% of patients in group 1 experienced cardiac death versus 11% in group 2 (p < 0.0005). By Cox model analysis, prolongation of a short DT emerged as the single best predictor of survival (chi-square 15.70). CONCLUSIONS: The prolongation of an initially short DT obtained with long-term optimal oral therapy predicts a more favorable outcome in clinically stable patients with CHF.

Cardiovascular Agents↗

PubMed1998

[Pulmonary uptake of thallium-201 at rest and diastolic function in patients with ischemic cardiopathy and left ventricular dysfunction].

An elevated thallium-201 lung uptake after stress is currently considered a marker of severe coronary artery involvement and related to adverse prognosis. The meaning of this scintigraphic finding on rest thallium-201 images is yet poorly investigated. We compared the thallium-201 lung uptake and the left ventricular diastolic function from mitral Doppler in 24 patients (64 +/- 10 years) with ischemic heart disease and severe left ventricular dysfunction (ejection fraction 28 +/- 10%). All patients underwent a 3-view planar rest-redistribution thallium-201 and 2D-echo studies within 6 days, while clinically stable. The amount of thallium-201 lung uptake was quantified as the ratio (L/H) between the activity in a left lung region of interest (L) and that observed in the left ventricle (H). From mitral Doppler, early (E) and late (A) filling velocities, the E/A ratio and the deceleration time of early filling (DecT) were calculated. An elevated L/H (> or = 0.54) was observed in 9 patients (37%). They showed a lower ejection fraction (20 +/- 4% vs 33 +/- 10% in patients with normal L/H; p < 0.01) and a higher wall motion score index (2.5 +/- 0.4 vs 2.1 +/- 0.4, p < 0.05). A significant inverse linear relation was observed between L/H and the left ventricular ejection fraction (r = -0.70); no significant relation was observed between L/H and left ventricular end-diastolic volumes or wall motion score index. A significant linear relation was also observed between L/H and E/A (r = 0.74; p < 0.001) as well as L/H and DecT (r = -0.61; p < 0.001); an even stronger, inverse, relation was found between L/H and A (r = -0.81; p < 0.001). An abnormal L/H identified 80% of patients with a restrictive filling pattern (specificity 93% and accuracy 88%, respectively). In conclusion, in stable patients with ischemic heart disease and ventricular dysfunction, L/H on rest thallium-201 images is closely correlated with Doppler indexes of left ventricular diastolic filling dynamic; an abnormal L/H is highly predictive of a restrictive filling pattern.

Aged↗

PubMed1996

Independent and incremental prognostic value of Doppler-derived mitral deceleration time of early filling in both symptomatic and asymptomatic patients with left ventricular dysfunction.

OBJECTIVES: This study sought to investigate the relative and incremental prognostic value of demographic, historical, clinical, echocardiographic and mitral Doppler variables in patients with left ventricular systolic dysfunction. BACKGROUND: The prognostic value of diastolic abnormalities as assessed by mitral Doppler echocardiography has yet to be defined. METHOD: A total of 508 patients with left ventricular ejection fraction < or = 35% were followed up for a mean (+/- SD) period of 29 +/- 11 months. RESULTS: During the follow-up period, 148 patients (29.1%) were admitted to the hospital for congestive heart failure, and 100 patients (19.7%) died. By Cox model analysis, Doppler-derived mitral deceleration time of early filling < or = 125 ms (relative risk [RR] 1.93, 95% confidence interval [CI] 1.4 to 3.7), New York Heart Association functional class III or IV (RR 1.49, 95% CI 1.4 to 2.3), ejection fraction < or = 25% (RR 1.85, 95% CI 1.6 to 2.9), third heart sound (RR 2.06, 95% CI 1.8 to 3.2), age > 60 years (RR 1.95, 95% CI 1.8 to 3.1) and left atrial area > 18 cm2 (RR 1.73, 95% CI 1.6 to 2.7) were all found to be independent and additional predictors of all-cause mortality, and deceleration time was the single best predictor (chi-square 37.80). When all these significant variables were analyzed in hierarchic order, after age, functional class, third sound, ejection fraction and left atrial area, deceleration time still added significant prognostic information (global chi-square from 9.2 to 104.7). Also, deceleration time was the strongest independent predictor of hospital admission for congestive heart failure (RR 4.88, 95% CI 3.7 to 6.9) and cumulative events (congestive heart failure or all-cause mortality, or both; RR 2.44, 95% CI 2.0 to 3.8) in both symptomatic and asymptomatic patients. CONCLUSIONS: Deceleration time of early filling is a powerful independent predictor of poor prognosis in patients with left ventricular systolic dysfunction, whether symptomatic or asymptomatic. A short (< or = 125 ms) deceleration time by mitral Doppler echocardiography adds important prognostic information compared with other clinical, functional and echocardiographic variables.

Cohort Studies↗

PubMed1996

[Exertion-induced myocardial ischemia has little influence on ventricular remodeling in post-infarction patients with preserved systolic function].

BACKGROUND: The effects of acute and recurrent ischemia on ventricular function are well documented. However, the role of residual exertional ischemia in the remodelling process after infarction has not yet been established. In this study, we investigated whether exercise-induced myocardial ischemia influences left ventricular remodelling in patients with recent myocardial infarction and preserved left ventricular function and volumes. METHODS: Sixty-four patients with a first anterior Q wave myocardial infarction were studied at 5 weeks by rest echocardiography and exercise scintigraphy; the echocardiographic examination at rest was repeated 6 months later. Based on the presence and extent of reversible perfusion defects on exercise scintigraphy, patients were classified as having no exertional ischemia (group 1, n = 13 [20%]), mild to moderate ischemia (group 2, n = 32 [50%]) and severe exertional ischemia (group 3, n = 19 [30%]). RESULTS: At 5 weeks after infarction left ventricular volumes, ejection fraction, percent wall motion abnormalities and regional dilatation were similar in the three groups. After 6 months, end-diastolic and end-systolic volumes and regional dilatation did not change in patients in all groups, while ejection fraction and percent wall motion abnormalities showed a slight but significant (p < 0.01) improvement in all groups. CONCLUSIONS: Exercise-induced myocardial ischemia, either mild or severe, does not affect ventricular remodelling and function after myocardial infarction in patients with preserved ejection fraction.

Adult↗

PubMed1996

[A paradigmatic case of partial agenesis of the pericardium].

Complete or partial absence of the pericardium is an uncommon congenital abnormality. Since its first description, several cases have been reported. Although the clinical and instrumental features of this defect are well described, at present it is often overlooked. We report a case of a 19-year old boy referred to our Echocardiography laboratory because of a suspected interatrial septal defect. For this reason it has been recommended to undergo cardiac catheterization. The patient, completely asymptomatic, had a negative physical examination. The echocardiogram excluded the presence of an interatrial septal defect, but some abnormalities, regarding overall right-sided heart, were found (paradoxical interventricular septal movement, apparent right-sided heart enlargement, with unusual bulging of the apex of the right ventricle, an excessive basculant heart movement). In the absence of any other heart disease, we thought that these abnormalities reflected a congenital absence of the pericardium. Indeed, the chest X-ray showed some features, considered patognomonic for congenital absence of the pericardium (levoposition of the heart, lung interposition between the diaphragm and the base of the heart and between the aorta and pulmonary artery). Nuclear magnetic resonance study showed the absence of the pericardium in the posterior and posterolateral wall, confirming our suspicion. Furthermore, the posterior wall of the heart leaned to herniate through the pericardial defect. Since the partial absence of the pericardium can lead to severe complications, surgery was recommended. The correct diagnosis of this disease is very important because of its prognostic implications; this case represents a further contribution to the understanding of this defect.

Adult↗

PubMed1995

Residual exertional ischemia and unfavorable left ventricular remodeling in patients with systolic dysfunction after anterior myocardial infarction.

OBJECTIVES: This study investigated whether exercise-induced myocardial ischemia influences left ventricular remodeling after anterior myocardial infarction. BACKGROUND: The effects of acute and recurrent ischemia on ventricular function are well established. However, to our knowledge the role of exertional ischemia in the remodeling response after infarction has not been investigated. METHODS: Ninety-one patients with a first anterior Q wave myocardial infarction were studied at 5 weeks by rest echocardiography and exercise scintigraphy. The echocardiographic examination was repeated 6 months later. On the basis of the presence and extent of reversible perfusion defects on exercise scintigraphy, patients were assigned to groups with no exertional ischemia (group 1, n = 20 [22%], mild to moderate ischemia (group 2, n = 45 [49%]) and severe exertional ischemia (group 3, n = 26 [29%]). RESULTS: Initial left ventricular volumes were similar, and no differences were found among the three groups in the remodeling response over the 6-month period of the study. However, patients in groups 2 and 3 with an ejection fraction < or = 40% showed significant (p < 0.01) ventricular enlargement over time, which was similar between the two groups (end-diastolic volume [mean +/- SD] from 74 +/- 13 to 80 +/- 17 ml/m2 in group 2 and from 72 +/- 11 to 81 +/- 19 ml/m2 in group 3; regional dilation from 42 +/- 16% to 52 +/- 22% in group 2 and from 38 +/- 18% to 46 +/- 27% in group 3). In contrast, ventricular dimensions did not change in group 1 patients with an ejection fraction < or = 40% as well as in patients in all three groups with an ejection fraction > 40%. CONCLUSIONS: Exercise-induced myocardial ischemia may contribute to progressive ventricular enlargement in patients with poor left ventricular function after a large anterior myocardial infarction.

Analysis of Variance↗

PubMed1995

[Estimate of lung capillary pressure and identification of the "pseudonormal" transmitral flow pattern in patients with severe systolic dysfunction of the left ventricle].

OBJECTIVES: Aim of this study was to investigate whether Doppler-derived transmitral flow velocity variables would allow a reliable estimate of pulmonary capillary wedge pressure in patients with left ventricular systolic dysfunction and normal mitral flow velocity pattern, and would then predict the presence of a "pseudonormal" transmitral flow velocity profile. BACKGROUND: Abnormal relaxation and increased chamber stiffness have opposing effects on the left ventricular filling pattern. When both abnormalities are present at the same time, as often occurs in patients with systolic dysfunction, the mitral pattern may appear to be normal: in this case the ability of Doppler recording to assess diastolic function and predict left ventricular filling pressure may be significantly compromised. METHOD: Pulmonary capillary wedge pressure (PWP) and Doppler transmitral flow velocity profile were simultaneously recorded in 70 postinfarction patients with ejection fraction < or = 35% and mitral flow velocity pattern apparently normal (E/A ratio between 1 and 2). Doppler traces were analyzed using a microcomputer-based digitizing system, and the following variables were measured: peak flow velocity in early diastole (E) and during atrial contraction (A), peak E/A wave velocity ratio and the deceleration time (Dec T) of early diastolic flow. RESULTS: Mean E/A ratio was 1.3 +/- 0.2 and mean PWP was 17 +/- 7 mm Hg. Forty-two patients had a PWP < 20 mm Hg and the remaining 28 patients (40%) had PWP > or = 20 mm Hg. Peak E, peak A and E/A ratio were similar in the two groups, whereas Dec T was significantly (p < 0.001) lower in patients with > or = 20 mm Hg PWP (93 +/- 15 vs 146 +/- 19 msec). A very weak correlation was found between PWP and both E and A velocity (r = 0.14 and r = 0.09, respectively). Furthermore, no correlation was found between E/A ratio and PWP (r = 0.08). Conversely, a very close negative correlation was observed between Dec T of early filling and PWP (r = -0.96). Sensitivity and specificity of < or = 120 ms in Dec T in predicting > or = 20 mm Hg in PWP were 100% and 99%, respectively. CONCLUSIONS: These data point out the relevant role of Doppler-derived deceleration time of early diastole in predicting left ventricular filling pressure. In patients with left ventricular systolic dysfunction an apparently normal diastolic filling pattern is often associated with elevated PWP. Through the estimate of increased PWP, early deceleration time seems to provide an important means of differentiating a real normal from a pseudonormal or masked abnormal filling pattern caused by increased left ventricular filling pressure.

Adult↗

PubMed1994

Effects of nitroglycerin by technetium-99m sestamibi tomoscintigraphy on resting regional myocardial hypoperfusion in stable patients with healed myocardial infarction.

Myocardial sestamibi uptake reflects regional flow distribution and cellular integrity; however, some segments showing reduced tracer uptake at rest may consist of viable, although hypoperfused, myocardium. It is speculated that the administration of nitroglycerin (NTG) before the sestamibi injection would improve the tracer uptake in resting hypoperfused regions. Thirty-six stable patients with previous myocardial infarction (56 +/- 2 years; mean ejection fraction 42 +/- 2%), in whom perfusion defects could be seen at resting sestamibi tomography, repeated the scintigraphic study 2 to 6 days later, receiving NTG (0.3 to 0.6 mg sublingually) before the tracer injection. The size of the tracer uptake defect was quantified from circumferential profiles in 3 short-axis slices by integrating the area below the lower normal limit (mean -2 SD). After NTG, the mean perfusion defect significantly decreased (from 6,324 +/- 619 to 5,365 +/- 516, p < 0.01). The defect was reduced beyond the reproducibility limits in 20 patients (56%, group 1) and was unchanged or increased in 16 (44%, group 2). The resting sestamibi defect size was comparable between the 2 groups. The average percent reduction of the perfusion defect after NTG was 29 +/- 4% (range 7 to 74).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Circulation↗

PubMed1994

Doppler-derived mitral deceleration time of early filling as a strong predictor of pulmonary capillary wedge pressure in postinfarction patients with left ventricular systolic dysfunction.

OBJECTIVES: The aim of this study was to investigate the correlations between Doppler-derived transmitral flow velocity variables and pulmonary capillary wedge pressure in patients with severe left ventricular systolic dysfunction. BACKGROUND: Abnormal relaxation and increased chamber stiffness have opposing effects on the left ventricular filling pattern. When both abnormalities are present at the same time, as often occurs in patients with systolic dysfunction, the ability of Doppler recording to assess diastolic function and predict left ventricular filling pressure may be significantly compromised. METHOD: Pulmonary capillary wedge pressure and Doppler transmitral flow velocity profile were simultaneously recorded in 140 postinfarction patients with ejection fraction < or = 35%. RESULTS: Correlation between the ratio of mitral peak flow velocity in early diastole to peak flow velocity in late diastole (E/A ratio) and pulmonary capillary wedge pressure was weak (r = 0.65). Although the specificity of E/A > or = 2 in predicting > or = 20 mm Hg in pulmonary capillary wedge pressure was high (99%), its sensitivity was low (43%). Conversely, a very close negative correlation was found between mitral deceleration time of early filling and pulmonary capillary wedge pressure (r = -0.90). Sensitivity and specificity of < or = 120 ms in deceleration time in predicting > or = 20 mm Hg in pulmonary capillary wedge pressure were 100% and 99%, respectively. CONCLUSIONS: Doppler-derived mitral deceleration time of early filling provides a simple and accurate means of estimating pulmonary capillary wedge pressure that is particularly useful in patients with a normal or normalized mitral flow velocity pattern.

Adult↗

PubMed1994

Spontaneous delayed recovery of perfusion and contraction after the first 5 weeks after anterior infarction. Evidence for the presence of hibernating myocardium in the infarcted area.

BACKGROUND: In patients with ventricular dysfunction caused by stunning or hibernation, it is not clear when complete recovery of the salvaged myocardium occurs after acute myocardial infarction. The purpose of this study was to determine whether a delayed recovery of perfusion and contraction continues even after the subacute phase. METHODS AND RESULTS: We prospectively studied 71 consecutive male patients with first uncomplicated Q-wave anterior infarction. Resting regional blood flow distribution and contraction were assessed quantitatively 5 weeks and 7 months after the acute phase by serial sestamibi tomography and two-dimensional echocardiography. Coronary angiography also was performed in 52 patients. Overall, at 7 months there was an improvement in the perfusion defect severity (1019 +/- 811 versus 1365 +/- 821 at 5 weeks, P < .001) as well as in the extent of abnormal wall motion (28 +/- 19% versus 32 +/- 15%, P < .001) and left ventricular ejection fraction (53 +/- 14% versus 50 +/- 13%, P < .01). Among the 68 of 71 patients showing resting perfusion defects at 5 weeks, two groups were identified: 47 (group 1) who showed a significant (beyond the reproducibility limits) 7-month reduction of the resting perfusion defect, and 21 patients (group 2) in whom the perfusion defect remained unchanged. Ejection fraction and the extent of abnormal wall motion significantly (P < .01) improved in group 1 but not in group 2. Despite the presence of a comparable perfusion defect size between the two groups at 5 weeks after infarction, group 1 already showed a better regional and global ventricular function (P < .05). No significant differences were found between the two groups regarding age, medical therapy, the extent of underlying coronary disease, thrombolysis in the acute phase, Thrombolysis in Myocardial Infarction grade of the infarct-related vessel, and presence of collaterals on angiography. CONCLUSIONS: After anterior Q-wave infarction, the recovery of perfusion and wall motion may continue well after the subacute phase. Several patients exhibit relative hypoperfusion in viable tissue as late as 5 weeks after infarction, and a significant improvement of perfusion in the infarcted area commonly is observed between 5 weeks and 7 months. This delayed improvement of perfusion is associated with a delayed improvement of contractile function in the infarcted area after the first 5 weeks, which may continue for up to 7 months, suggesting the presence of hibernating myocardium in the infarcted area. Despite similar perfusion defect sizes, the level of regional function can be different at 5 weeks, and measurements taken around this time may not accurately estimate the eventual recovery of function.

Adult↗

PubMed1993

Long-term physical training and left ventricular remodeling after anterior myocardial infarction: results of the Exercise in Anterior Myocardial Infarction (EAMI) trial. EAMI Study Group.

OBJECTIVES: The aim of this multicenter randomized study was to investigate whether long-term physical training would influence left ventricular remodeling after anterior myocardial infarction. BACKGROUND: Exercise is currently recommended for patients after myocardial infarction; however, the effects of long-term physical training on ventricular size and remodeling still have to be defined. METHODS: Patients with no contraindications to exercise were studied 4 to 8 weeks after anterior Q wave myocardial infarction and 6 months later by echocardiography at rest and bicycle ergometric testing. After the initial study, patients were randomly allocated to a 6-month exercise training program (n = 49) or a control group (n = 46). A computerized system was used to derive echocardiographic variables of ventricular size, function and topography. RESULTS: After 6 months, a significant (p < 0.01) increase in work capacity (from 4,596 +/- 1,246 to 5,508 +/- 1,335 kp-m) was observed only in the training group, whereas global ventricular size, regional dilation and shape distortion did not change in either the control or the training group. However, compared with patients with an ejection fraction > 40%, patients with an ejection fraction < or = 40% had more significant (p < 0.001) ventricular enlargement at entry and demonstrated further (p < 0.01) global and regional dilation after 6 months, in both the control and the training group (end-diastolic volume from 77 +/- 14 to 85 +/- 17 ml/m2 in the control group and from 74 +/- 11 to 77 +/- 15 ml/m2 in the training group; regional dilation from 46 +/- 18% to 57 +/- 21% in the control group and from 42 +/- 18% to 44 +/- 26% in the training group). Ventricular size and topography did not change in patients with an ejection fraction > 40%. CONCLUSIONS: Patients with poor left ventricular function 1 to 2 months after anterior myocardial infarction are prone to further global and regional dilation. Exercise training does not appear to influence this spontaneous deterioration. Thus, postinfarction patients without clinical complications, even those with a large anterior infarction, may benefit from long-term physical training without any additional negative effect on ventricular size and topography.

Electrocardiography↗