Effects of early enalapril treatment on global and regional wall motion in acute myocardial infarction. CONSENSUS II Multi Echo Study Group

Comparison of Left Ventricular Volumes Measured by 3DE, SPECT and CMR

BACKGROUND

Information regarding left ventricular (LV) volume and left ventricular ejection fraction (LVEF) has major diagnostic and prognostic value when assessing patients after ST-elevation myocardial infarction (STEMI). We aimed to investigate the agreement between measurement of LV volumes and LVEF by three-dimensional echocardiography (3DE), single-photon emission computed tomography (SPECT) and cardiac magnetic resonance (CMR) imaging in patients in a stable phase after STEMI.

METHODS

Fifteen patients underwent examinations by 3DE, SPECT and CMR three months after STEMI.

RESULTS

There was a significant bias in end-diastolic volume (EDV) measured by 3DE (–64 mL, p < 0.001) and SPECT (–55 mL, p < 0.001) compared with that measured by CMR. This was also the case for end-systolic volume (ESV) measured by 3DE (–36 mL, p < 0.001) and SPECT (–28 mL, p < 0.001). No significant differences were found between 3DE and SPECT for EDV or ESV. However, LVEF did not differ between the three methods. The agreement between all three methods was moderate (intra-class correlation coefficient [ICC] = 0.44) for LV volume and good for LVEF (ICC = 0.72).

CONCLUSIONS

LV volumes assessed by 3DE did not differ from SPECT, and despite larger LV volumes by CMR, measurements of LVEF showed good agreement between all three methods.

Contrast Enhancement and Image Quality Influence Two- and Three-dimensional Echocardiographic Determination of Left Ventricular Volumes: Comparison With Magnetic Resonance Imaging

Purpose:

To evaluate the effect of image quality and contrast enhancement (CE) on left ventricular (LV) volume determination by two- (2D) and three-dimensional (3D) echocardiography (2DE/3DE).

Methods:

We studied 32 post-myocardial infarction (MI) patients without (2DE/3DE) and with CE (CE2DE/CE3DE), in comparison with cardiac magnetic resonance imaging (CMR).

Results:

Two-dimensional echocardiography showed the largest negative bias versus CMR for diastolic and systolic volumes (−59, −28 mL, respectively) with lower biases for CE2DE (−37, −22 mL), 3DE (−31, −17 mL), and CE3DE (−17, −11 mL). Bias for ejection fraction (EF) ranged from −2.1% for 2DE to +1.4% for CE3DE. Agreement (intraclass correlation coefficient, ICC) for EF between CMR and 3DE (0.86 without and 0.85 with contrast) was better than for 2DE (0.73 without and 0.69 with contrast). The inter-/intra-observer coefficients of variation for EF varied from 16%/10% (2DE) to 6.9%/6.6% (CE2DE), and 8.3%/4.8% (3DE) to 6.7%/6.8% (CE3DE), respectively. The agreement (ICC) with CMR for EF measured by 2DE/3DE changed from 0.64/0.84 with poor image quality to 0.81/0.87 with moderate to good image quality.

Conclusions:

Three-dimensional echocardiography was more accurate than 2DE for estimating LV volumes, with less inter-/intra-observer variability in EF values. Contrast enhancement improved accuracy for both 2DE and 3DE and improved the inter-observer variability of EF estimates for 2DE and 3DE. Image quality had more impact on the agreement of EF values with CMR for 2DE than for 3DE. Our results emphasize the importance of using the same technique for longitudinal studies of LV EF and specially LV volumes.

A remarkable medical story: benefits of angiotensin-converting enzyme inhibitors in cardiac patients

The development of angiotensin-converting enzyme inhibitors (ACE inhibitors) has been one of the most remarkable stories in the treatment of cardiovascular diseases. Angiotensin converting enzyme inhibitors have several acute and sustained hemodynamic effects that are beneficial in the presence of left ventricular (LV) dysfunction. They increase cardiac output and stroke volume and reduce systemic vascular resistance as well as pulmonary capillary wedge pressure. The hemodynamic benefits are associated with improvement in the signs and symptoms of congestive heart failure (CHF) as well as decreased mortality, regardless of the severity of CHF. In patients with asymptomatic LV dysfunction, therapy with ACE inhibitors prevented the development of CHF and reduced hospitalization and cardiovascular death. They also increase survival when administered early after an acute myocardial infarction (MI). Most recently, ACE inhibition was associated with improved clinical outcomes in a broad spectrum of high-risk patients with preserved LV function. The mechanism of ACE inhibitors benefits is multifactorial and includes prevention of progressive LV remodeling, prevention of sudden death and arrhythmogenicity and structural stability of the atherosclerotic process. Evidence suggests that ACE inhibitors are underutilized in patients with cardiovascular diseases. Efforts should be directed to prescribe ACE inhibitors to appropriate patients in target doses. It is reasonable to believe that ACE inhibitors have a class effect in the management of LV dysfunction with or without CHF and acute MI. Whether the same is true for ACE inhibitors in the prevention of ischemic events is not known yet.

How long should angiotensin-converting enzyme inhibitors be given to patients following myocardial infarction: implications of the HOPE trial

Long-term treatment with angiotensin-converting enzyme inhibitors reduces post-infarction morbidity and mortality in patients with left ventricular (LV) systolic dysfunction or symptomatic heart failure. Until recently, the effect of such treatment in patients with preserved LV function has not been known. The results from the Heart Outcome Prevention Evaluation trial have indicated that long-term treatment with ramipril leads to a significant reduction in cardiovascular events in patients with atherosclerotic disease, including those with prior myocardial infarction and preserved LV function. These results suggest that long-term angiotensin-converting enzyme inhibition should also be considered in post-infarction patients with normal cardiac function.

Time course of left ventricular remodeling after myocardial infarction: a two-dimensional echocardiographic study

In order to forecast the clinical course of acute myocardial infarction (MI), the time course of the functional changes of the left ventricular myocardium that result in remodeling was evaluated with two-dimensional echocardiography (2DE). The study group comprised 45 patients with anterior MI treated with successful percutaneous transluminal coronary angioplasty. 2DE studies were performed on days 1, 3, 7 and 14; months 1 and 3 and 1 year after MI, and the following parameters were recorded: (1) infarcted wall thickness, (2) traced length of the endocardium and of the epicardium on end-diastolic apical long axis images, and (3) wall motion score (total of asynergy scores of 16 segments of left ventricle (LV); normal: 0, hypokinesis: 1, akinesis: 2, dyskinesis: 3). According to the peak creatine kinase (CK) level, patients were classified into L group (CK > or =8000 U/L, n=16), M group (8000> CK > or =4000, n=13) and S group (CK <4000, n=16). The following results were obtained. (1) There was progressive thinning of the infarcted myocardium up to 1 month after (1 day: 9.3+/-1.7, 14 days: 6.3+/-1.7 vs 1 month: 5.9+/-1.8 mm, p<0.05; vs 1 year: 5.9+/-1.9 mm, NS). (2) Dilatation of the LV cavity occurred shortly after MI and continued up to 14 days (endocardium at 14 days: 176.8+/-13.6 vs 1 day: 164.1+/-11.4 mm, p<0.01; vs 1 year: 176.3+/-12.7 mm, NS). (3) The wall motion score improved rapidly by 14 days, and continued to improve gradually to 1 year (1 day: 12.2+/-3.4, 14 days: 6.8+/-4.0, 1 year: 4.6+/-3.1). (4) The expansion ratio (endocardial length at 14 days/1 day) was significantly greater in the L group than in the S group (p<0.05). Comparing the groups, the LV cavity of the L group remained dilated up to 14 days, whereas that of the S and M groups was dilated up to 7 days (L group 14 days: 179.3+/-11.9 vs 1 day: 156.9+/-9.2mm, p<0.01; vs 1 year: 180.0+/-14.1 mm, NS) (S group 7 days: 171.7+/-13.6 vs 1 day: 161.5+/-7.2 mm, p<0.01; vs 1 year: 172.7+/-14.4 mm, NS) (M group 7 days: 170.5+/-10.5 vs 1 day: 157.7+/-14.5 mm, p<0.05; vs 1 year: 177.08+/-9.6 mm, NS). Serial 2DE on days 1 and 14 after MI were useful for evaluating the course of LV remodeling and to forecast cardiac function in the chronic phase of MI. Determining the length of hospital stay on the basis of infarction size is justified.

Role of nitrates for the therapy of coronary artery disease patients in the years beyond 2000

Vasodilator therapy with nitrates has been used for almost a century to bring relief to patients suffering from angina. The acute anti-ischemic effects of nitro-vasodilators for the treatment and prevention of anginal attacks is unquestioned. In addition, nitrates are administered in order to reduce symptomatic and silent ischemic episodes, in patients with proven coronary heart disease who exert ST segment alterations on Holter monitoring. The reduction in total ischemic burden may result in an improved prognosis with regard to infarct prevention and possible prevention of deterioration of left ventricular function due to repetitive episodes of myocardial ischemia. In patients with unstable angina, administration of nitrates significantly diminishes ischemic episodes and reduces the number of clinically symptomatic anginal attacks. The prevention of left ventricular dilatation in patients within the first few days and months following acute myocardial infarction may be due to the reduced preload. In patients with heart failure, preload reduction with nitrates and afterload reduction with hydralazine was tested versus angiotensin converting enzyme (ACE) inhibitors. However, unfortunately, very few data are available concerning the combination therapy of ACE inhibitors and nitrates in heart failure and following acute myocardial infarction. Long-term continuous administration of high doses of nitrates may cause nitrate tolerance, thus reducing the vasodilator potency of these drugs. Since nitrates were introduced into medical therapy many decades before randomized controlled trials were performed, and evidence-based medicine became the basic principal for medical therapy, there are still indications and situations where the full therapeutic potential of nitrates is not being fully appreciated. During recent decades, other anti-ischemic drugs, i.e., beta-receptor agonists and calcium channel blockers, were introduced into the clinical setting and contributed to an optimized therapy for patients with coronary heart disease. Nevertheless, due to their proven and unsurmounted symptomatic efficacy, nitrates will remain one of the cornerstones of acute and long-term therapy of patients with coronary heart disease far beyond the year 2000.

Clinical assessment of indication for ACE-inhibitor treatment early after acute myocardial infarction

An investigation was conducted to assess whether an algorithm based on simple clinical information would suffice to classify patients with acute myocardial infarction, with respect to indication for angiotensin-converting-enzyme inhibitor treatment. One hundred consecutive patients with myocardial infarction were prospectively studied. Based on clinical, radiological, electrocardiographic and biochemical information, the patients were classified as having (a) significantly depressed left ventricular function (ejection fraction < or = 40%) justifying treatment with angiotensin-converting-enzyme inhibitors (ACEI), (b) preserved ventricular function (ejection fraction > 40%) making ACEI unnecessary, or (c) indeterminate ventricular function, requiring further examination. Using a blinded design, ejection fraction was determined by echocardiography and radionuclide ventriculography. A clinical assumption of reduced left ventricular function had a predictive value of an echocardiographically determined ejection fraction < or = 40% of 83% (n = 23). Clinical criteria of good ventricular function had a predictive value of ejection fraction > 40% of 96% (n = 24). In these two groups clinical misclassification occurred in five patients with ejection fraction within the range of 39-45%. Left ventricular function was found to be clinically indeterminate in 53 of the 100 patients. Ejection fraction values assessed by radionuclide ventriculography (n = 44) were on average 9.3%-points lower than echocardiographic values. The indication for ACEI can apparently be determined on the basis of readily available clinical information in approximately 50% of patients with acute myocardial infarction.

Effects of enalapril on left ventricular function and exercise performance after a first acute myocardial infarction. The EDEN Study Investigators

AIMS

To study the effects of early use of enalapril on left ventricular function and exercise capacity after a first acute myocardial infarction, 356 patients without overt signs of congestive heart failure were randomly allocated to receive placebo or enalapril between days 7 and 14 after a first myocardial infarction. The study was conducted double-blind in 40 hospitals throughout Spain.

METHODS AND RESULTS

At baseline and after 26 weeks of follow-up exercise stress tests, Doppler-echocardiograms and isotopic ventriculography were performed in study participants. At the end of follow-up, patients in the enalapril group had lower end-systolic volume compared to those in the placebo group (55 vs. 62 ml; P=0.05). No difference in exercise capacity was evident between both groups.

CONCLUSION

The present study shows that enalapril therapy administered between 7 and 14 days after a first acute myocardial infarction decreases end-systolic volume and may inhibit the remodeling process of the left ventricle.