Changes in left and right ventricular performance and volumes in seven-year survivors of acute myocardial infarction

Impact of the number of image planes of real-time three-dimensional echocardiography on the accuracy of left atrial and ventricular volume measurements

Real-time three-dimensional (3D) echocardiography (RT-3DE) has emerged as a new technique in measuring left atrial and ventricular volume. However, the impact of cutting planes of RT-3DE on the accuracy of volume measurement in patients with a normal or enlarged heart is still unknown. We enrolled 30 normal subjects (control group) and 30 patients with heart failure (patient group). RT-3DE was performed to measure maximal volume of the left atrium (LAVmax) and left ventricular end-diastole volume (LVEDV) with 2-, 4-, 8- and 16-cutting planes, compared with cardiac magnetic resonance imaging (CMRI). In both groups, LAVmax by RT-3DE using 2- and 4-cutting planes was significantly underestimated (mean difference: -10.4 +/- 16.6 mL, p = 0.001 and -8.8 +/- 14.2 mL, p = 0.002 in the control group and -13.4 +/- 19.6 mL, p = 0.001 and -11.2 +/- 17.5 mL, p = 0.001 in the patient group, respectively). These differences became nonsignificant when 8- and 16-cutting planes were adopted (mean difference: -2.1 +/- 7.6 mL and -1.9 +/- 7.4 mL in the control group and -2.7 +/- 8.4 mL and -2.2 +/- 8.3 mL in the patient group, respectively). The agreement for LVEDV was acceptable when 4- or more cutting planes were used in the control group and when 8- or 16-cutting planes were used in the patient group. The time expense for data analysis of LAVmax with 8-image planes was only 7 +/- 4 min in the control group and 6 +/- 5 min in the patient group, almost halving that of the 16-image planes. Similarly, 4- and 8-cutting planes were required for an accurate measurement of LVEDV in the control and patient groups, respectively. In conclusion, RT-3DE with 8-cutting planes is both accurate and timesaving for measurement of LAVmax and LVEDV in patients with normal or enlarged left atria and ventricles.

Efficacy of continuous low-dose hANP administration in patients undergoing emergent coronary artery bypass grafting for acute coronary syndrome

BACKGROUND

Low-dose continuous human atrial natriuretic peptide (hANP) administration during cardiac surgery has been reported on previously. In the present study, the efficacy of the therapy during emergent coronary artery bypass grafting (CABG) for acute coronary syndrome (ACS) is investigated.

METHODS AND RESULTS

One hundred and twenty-four patients patients undergoing emergent CABG for ACS were divided into 2 groups; a group receiving administration of hANP (hANP group) and a group not receiving hANP infusion (non-hANP group). The postoperative peak levels of creatine kinase-MB were significantly lower in the hANP group as compared with those in the non-hANP group. The incidence of postoperative arrhythmias was also significantly lower in the hANP group as compared with that in the non-hANP group. The postoperative brain natriuretic peptide was significantly lower in the hANP group as compared with that in the non-hANP group until 1 year after the operation. The free-rate of cardiac events after the operation was also significantly higher in the hANP group as compared with that in the non-hANP group.

CONCLUSIONS

It is therefore considered that hANP might not only be effective for overcoming some major shortcomings of cardiopulmonary bypass, but also might be effective to attenuate ischemia-reperfusion injury, protect the myocardium, have an anti-arrhythmic effect, and suppress left ventricular remodeling.

Prognostic use of echocardiography 1 year after a myocardial infarction

BACKGROUND

Left ventricular (LV) and right ventricular (RV) function are known predictors of morbidity and mortality after an acute myocardial infarction (MI). However, the prognostic use of a late evaluation of cardiac function after an MI remains unclear.

METHODS

We analyzed echocardiograms obtained 1 year after MI in patients with LV dysfunction at baseline (ejection fraction [EF] < or = 40%) from 291 patients enrolled in the SAVE echocardiographic substudy who did not develop heart failure (HF) or a recurrent MI during this first year. Left ventricular EF and RV fractional area change were assessed.

RESULTS

After a median follow-up of 22 months after the 1-year echocardiogram, a low LVEF (< 30%) at 1 year was associated with an increased risk of death and/or HF (hazards ratio [HR] 2.7, 95% CI 1.3-5.3). Presence of RV dysfunction was also associated with an increased risk of death (HR 8.9, 95% CI 3.5-22.1), development of HF (HR 7.1, 95% CI 3.4-15.0), and the composite end point of death or HF (HR 7.6, 95% CI 4.1-14.2). In multivariate analyses, both low LVEF and RV dysfunction remained independently predictive of the composite end point of death or HF. Patients with biventricular dysfunction were at the greatest risk of death and/or HF (HR 19.4, 95% CI 8.2-46.0) in follow-up.

CONCLUSIONS

In a stable population of survivors of MI, impaired LV and RV function at 1 year after MI are independently and additively predictive of increased risk of HF or death.

Metoprolol CR/XL Improves Systolic and Diastolic Left Ventricular Function in Patients with Chronic Heart Failure

AIMS

To investigate whether metoprolol controlled release/extended release (CR/XL) once daily would improve diastolic and systolic left ventricular function in patients with chronic heart failure and decreased ejection fraction.

METHODS

In an echocardiographic substudy to the Metoprolol CR/XL Randomized Intervention Trial in Heart Failure (MERIT-HF), 66 patients were examined three times during a 12-month period blinded to treatment group, assessing left ventricular dimensions and ejection fraction, and Doppler mitral inflow parameters, all measured in a core laboratory.

RESULTS

In the metoprolol CR/XL group left ventricular ejection fraction increased from 0.26 to 0.31 (P = 0.009) after a mean observation period of 10.6 months, and deceleration time of the early mitral filling wave (E) increased from 189 to 246 ms (P = 0.0012), time velocity integral of E-wave increased from 8.7 to 11.2 cm (P = 0.018), and the duration of the late mitral filling wave (A) increased from 122 to 145 ms (P = 0.014). No significant changes were seen in the placebo group regarding any of these variables.

CONCLUSION

Metoprolol CR/XL once daily in addition to standard therapy improved both diastolic and systolic function in patients with chronic heart failure and decreased ejection fraction.

Early changes in left ventricular volume and function are predictors for long-term remodeling in patients with acute transmural myocardial infarction and preserved systolic function

BACKGROUND

We sought to describe the degree of long-term left ventricular (LV) remodeling after acute transmural myocardial infarction with preserved LV systolic function, and to evaluate whether Doppler echocardiographic parameters in the early phase could predict this process.

METHODS

A total of 60 patients without heart failure and with LV ejection fraction > or = 0.40 (mean 0.48 +/- 0.054), were followed up with Doppler echocardiographic examinations at baseline, 3 months, and 1 and 2 years.

RESULTS

There was a significant increase in LV end-diastolic volume index of 7% (P =.006) and LV end-systolic volume index of 8% (P =.03), and no change in ejection fraction. This remodeling was confined to 7 patients (12%) with a significant increase in LV end-diastolic volume index above 20 mL/m(2). There was also a significant increase in the deceleration time of both the early mitral filling wave (Delta early mitral filling wave = 58 milliseconds, P <.0005) and the diastolic forward component of pulmonary venous flow (Delta diastolic forward component of pulmonary venous flow = 61 milliseconds, P <.0005), and a shift in filling pattern with increasing prevalence of abnormal relaxation. Changes in end-diastolic volume index were predicted by baseline early mitral filling wave less than 100 milliseconds, but the most powerful predictors of 2-year remodeling were volume changes at 3 months.

CONCLUSION

Twelve percent of patients with Q-wave infarction and ejection fraction > or = 0.40 experienced significant LV dilatation at 2 years, and this late remodeling was partly related to baseline filling characteristics.

[Evolution of systolic function and myocardial perfusion, evaluated by gated-SPECT, in the first year after acute myocardial infarction]

INTRODUCTION AND OBJECTIVES

Systolic function and myocardial perfusion are evaluated before hospital discharge and can change during follow-up. The purpose of this study was to evaluate these parameters by gated-SPECT in the first year after acute myocardial infarction.

PATIENTS AND METHOD

We studied 74 consecutive patients with a first uncomplicated acute myocardial infarction (49 infero-lateral and 25 anterior) by stress-rest 99mTc-tetrofosmin and rest-gated-SPECT before hospital discharge (6-8 days after admission) and one year after myocardial infarction.

RESULTS

The ejection fraction (EF) increased > 5% in 51% of infero-lateral infarcts and 28% of non-revascularized anterior infarcts. EF increased significantly (48.4 8% to 54.6 8.7%; p < 0.0001, mean difference: 6.2; 95% IC, 2.8-9.5) and systolic volume decreased (51.3 19.2 ml to 44.3 19.4 ml; p = 0.001; mean diff.: 7.67; 95% IC, 1.5-13.8) in infero-lateral infarctions. The rest perfusion index in the necrotic region improved (2.3 0.57 to 2.17 0.58; p = 0.004; mean diff.: 0.18; 95% IC, 0.003-0.36) in infero-lateral infarcts and the ischemia index remained unchanged between the first and second studies.

CONCLUSIONS

Left ventricular systolic function can change during the first year of evolution, a significant improvement being seen in infero-lateral infarctions. The ejection fraction increased > 5% in half of these patients, as opposed to only a quarter of anterior infarctions. This improvement was associated to increased myocardial perfusion at rest.

In-hospital heart failure, first-year ventricular dilatation and 10-year survival after acute myocardial infarction

BACKGROUND

Little is known about the factors that determine long-term prognosis in patients who have survived the first year after acute myocardial infarction (AMI).

AIMS

To study the influence of left and right ventricular (LV and RV) dilatation during the first year after AMI on subsequent 10-year survival in comparison with in-hospital heart failure and other established prognostic indices.

METHODS

Radionuclide ventriculography was performed before the era of thrombolysis and post-infarction ACE-inhibition in 57 patients with AMI at hospital discharge and again 1 year later, and compared with survival the ensuing 10 years.

RESULTS

After 1 year significant LV-dilatation (>20%) had occurred in 32 (56%) patients. One year after the re-investigation the mortality in these was 19% vs. 0% in patients without dilatation (P=0.02); after 5 years the difference was 38 vs. 12% (P=0.02), whereafter it declined and became insignificant at 10 years. Neither RV-dilatation, nor LVEF determined at discharge or at the 1-year reinvestigation influenced long-term survival. In contrast, clinical heart failure recorded during the hospital stay had a sustained negative influence on long-term survival.

CONCLUSION

Progressive LV dilatation after discharge and clinical heart failure during the hospital stay are both determinants of late survival after AMI, whereas LV ejection fraction at hospital discharge or 1 year later has little, if any, effect on survival beyond 1-year post-AMI.

Early predictors of left ventricular remodeling after acute myocardial infarction

Ventricular remodeling after acute myocardial infarction is characterized by alteration in left ventricular (LV) size, shape, and wall thickness and involves both the infarcted and the noninfarcted regions of the ventricle. These structural changes are the result of several distinct pathologic processes that contribute to progressive LV dilation: rearrangement of wall structure, myocyte hypertrophy, and increasing muscle mass without an increase in wall thickness (eccentric hypertrophy). The pathogenesis of LV remodeling is multifactorial. Multiple factors may in fact contribute at different stages from the time of coronary occlusion until the development of ventricular dilation: These include the magnitude of the loss of contractile elements, the abrupt alteration in systolic and diastolic loading conditions, the activation of circulating neurohormones and local autocrine trophic factors, and the patency of the infarct-related artery. Although remodeling occurring early after infarction may be an appropriate compensatory response to preserve ventricular function, recent observations have suggested that this long process has a deleterious effect on LV function and prognosis. Thus attempts to inhibit these structural changes have been the focus of recent experimental and clinical studies. This review focuses on interactive factors that influence postinfarction LV remodeling, emphasizing the role of some new emerging determinants such as the extent of surviving myocardium within the infarcted and noninfarcted zones.

Ventricular dilatation in the absence of ACE inhibitors: influence of haemodynamic and neurohormonal variables following myocardial infarction

OBJECTIVE

To examine the relation between patterns of ventricular remodelling and haemodynamic and neurohormonal variables, at rest and during symptom limited exercise, in the year following acute myocardial infarction in patients not receiving angiotensin converting enzyme (ACE) inhibitors.

DESIGN

A prospective observational study.

PATIENTS

65 patients recruited following hospital admission with a transmural anterior myocardial infarction.

METHODS

Central haemodynamics and neurohormonal activation at rest and during symptom limited treadmill exercise were measured at baseline before hospital discharge, one month later, and at three monthly intervals thereafter. PATIENTS were classified according to individual patterns of change in left ventricular end diastolic volumes at rest, assessed at each visit using transthoracic echocardiography.

RESULTS

In most patients (n = 43, 66%) ventricular volumes were unchanged or reduced. Mean (SEM) treadmill exercise capacity and peak exercise cardiac index increased at month 12 by 200 (24) seconds (p < 0.001 v baseline) and by 0.8 (0.4) l/min/m2 (p<0.05 v baseline), respectively, in this group. In patients with limited ventricular dilatation (n = 11, 17%) exercise capacity increased by 259 (52) seconds (p < 0.001 v baseline) and peak exercise cardiac index improved by 0.8 (0.7) l/min/m2 (NS). In the remaining 11 patients with progressive left ventricular dilatation, exercise capacity increased by 308 (53) seconds (p< 0. 001 v baseline) and peak exercise cardiac index similarly improved by 1.3 (0.7) l/min/m2 (NS). There were trends towards increased atrial natriuretic factor (ANF) secretion at rest and at peak exercise in this group.

CONCLUSIONS

Ventricular dilatation after acute myocardial infarction is a heterogeneous process that is progressive in only a minority of patients. Compensatory mechanisms, including ANF release, appear capable of maintaining and improving exercise capacity in most patients for at least 12 months, even in those with a progressive increase in ventricular size.