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Biomedical subjects

G A Lamas

Publications and source records attributed to G A Lamas.

At least 19 recordsLinked to original sources

Effect of infarct artery patency on prognosis after acute myocardial infarction. The Survival and Ventricular Enlargement Investigators.

BACKGROUND: In patients with acute myocardial infarction (MI), early restoration of patency of the infarct-related artery (IRA) leads to preservation of left ventricular function and improved clinical outcome. However, there is evidence that the benefits associated with a patent IRA are out of proportion to the observed improvement in ventricular function and may result not only from salvage of ischemic myocardium but also from the opening of the IRA beyond a narrow postinfarct time window. The objectives of this study were (1) to assess the effect of IRA patency on outcome of patients after acute MI with left ventricular dysfunction while controlling for differences in left ventricular ejection fraction and the extent of coronary disease and (2) to determine the effect of angiotensin-converting enzyme (ACE) inhibitor therapy on patients with patent as well as occluded infarct arteries. METHODS AND RESULTS: The Survival and Ventricular Enlargement (SAVE) study consisted of 2231 patients with a documented MI and a left ventricular ejection fraction < or = 40%. They were randomized to the ACE inhibitor captopril (50 mg TID) or placebo 3 to 16 days after MI and were followed for an average of 3.5 years. Left ventricular ejection fraction, measured with radionuclide left ventriculography, was repeated at the end of the follow-up period. The 946 patients in whom the patency of the IRA was established before randomization form the basis of this study. At cardiac catheterization averaging 4.2 days after infarction, 30.7% of patients had an initially occluded IRA. After revascularization, 162 of the 946 patients (17.1%) were left with an occluded IRA at the time of randomization. The 162 patients with persistently occluded IRAs and 784 with patent IRAs had similar clinical baseline characteristics, but those with occluded arteries had a slightly lower ejection fraction than the 784 patients with patent infarct arteries (30% versus 32%, P = .01). Cox proportional-hazards analyses showed that the independent predictors of all-cause mortality were hypertension (relative risk [RR] 1.94, P < .001), number of diseased coronary arteries (RR 1.68, P < .001), occluded IRA (RR 1.49, P = .039), ejection fraction (RR 1.36, P < .001), age (RR 1.10, P = .030), and use of beta-adrenergic receptor blocking agents (RR 0.60, P = .007). Independent predictors of a composite end point consisting of cardiovascular mortality, morbidity, or reduction of ejection fraction of > or = 9 units were occluded IRA (odds ratio [OR] 1.73, P = .002), hypertension (OR 1.71, P < .001), number of diseased vessels (OR 1.38, P < .001), ejection fraction (OR 1.18, P = .003), use of beta-adrenergic receptor blocking agents (OR 0.67, P = .007), and randomization to captopril (OR 0.70, P = .009). CONCLUSIONS: IRA patency within 16 days after MI predicts a favorable clinical outcome, independent of the number of obstructed coronary arteries or of left ventricular function. The beneficial effect of ACE inhibition is independent of patency status of the IRA. These findings support the need for additional, prospective clinical trials of late reperfusion in MI patients.

Adrenergic beta-Antagonists

Permanent pacemaker selection and subsequent survival in elderly Medicare pacemaker recipients.

BACKGROUND: Dual-chamber pacemakers have been in use for more than 15 years. Although they may confer a physiological advantage over single-chamber ventricular pacemakers, they are more expensive and have a generally shorter service life than single-chamber devices. We carried out the present study to identify patient subgroups who were preferentially receiving greater or lesser proportions of dual-chamber devices and to determine whether the selection of different types of pacemakers was associated with differences in mortality. METHODS AND RESULTS: We analyzed a 20% random national sample of all Medicare beneficiaries aged 65 years or older who underwent initial placement of a permanent pacemaker and were discharged in 1988, 1989, or 1990 (n = 36,312). The minimum follow-up for vital status was 1 year. The relation of pacemaker type to patient and provider characteristics was determined using logistic regression analysis. The relation between pacemaker type and mortality was determined using the Cox proportional hazards method. The proportion of dual-chamber systems that were received increased from 27.2% in 1988 to 37.0% in 1990 (P < .001). Dual-chamber pacemaker recipients were younger (P < .001) than ventricular pacemaker recipients. Other independent correlates of dual-chamber pacemaker selection included male sex (odds ratio and 95% confidence intervals, 1.18 and 1.12 to 1.24, respectively), atrioventricular block (1.59 and 1.51 to 1.67), congestive heart failure (1.14 and 1.08 to 1.20), atrial fibrillation (0.36 and 0.34 to 0.39), and the presence of a major noncardiac diagnosis (0.86 and 0.83 to 0.89). Nonmedical predictors of dual-chamber pacemaker selection included Medicaid eligibility (0.78 and 0.71 to 0.86), implantation in the western United States (1.19 and 1.10 to 1.29), implantation by a rural provider (0.70 and 0.65 to 0.76), hospitalization in a 500-bed-or-larger hospital (1.20 and 1.13 to 1.28), hospitalization in a private hospital (1.19 and 1.10 to 1.28), or hospitalization in a hospital with a catheterization laboratory (1.47 and 1.38 to 1.56). Dual-chamber pacemaker selection was an independent predictor of survival at 1 year (0.82 and 0.77 to 0.87) and at 2 years (0.82 and 0.77 to 0.87) after controlling for potentially confounding patient-level and hospital-level characteristics. CONCLUSIONS: The present study describes important variations in the clinical practice of cardiac pacing, many of which are not based on clinical characteristics. Furthermore, the selection of a dual-chamber pacemaker is associated with increased survival. These results underscore the need for prospective, outcome-based clinical trials of pacemaker mode selection.

Aged

Risk factors for the development of recurrent atrial fibrillation: role of pacing and clinical variables.

Atrial fibrillation recurs in many patients treated with antiarrhythmic therapy to maintain sinus rhythm. From March 1985 to August 1991, 214 patients with recurrent symptomatic chronic or paroxysmal atrial fibrillation for which conventional antiarrhythmic agents had failed were treated with propafenone or sotalol. Baseline demographic data including the presence of pacing therapy were collected. Life-table estimates of the duration of freedom from atrial fibrillation were constructed on the basis of pacemaker status. Of 214 patients, 26 (12.1%) had pacing therapy. Patients with dual-chamber pacing were more likely to remain in sinus rhythm at 6 months (80%) than were patients with ventricular pacing (40%) or patients without pacing therapy (55%) (p = 0.002). A Cox univariate regression analysis demonstrated that dual-chamber pacing in contrast to ventricular pacing or no pacing was associated with a lower risk of recurrent atrial fibrillation. Clinical parameters such as age, gender, left atrial size, fibrillation pattern, drug assignment, ejection fraction, and underlying cardiac disease did not alter the risk of recurrent atrial fibrillation. Dual-chamber pacing was associated with a decreased likelihood of recurrent atrial fibrillation even after adjustment for other clinical covariates in a multivariate model (p = 0.04). In patients with recurrent atrial fibrillation treated with propafenone or sotalol, dual-chamber pacing improved maintenance of sinus rhythm.

Atrial Fibrillation

Cost-effectiveness of captopril therapy after myocardial infarction.

OBJECTIVES: This study sought to assess the cost-effectiveness of captopril therapy for survivors of myocardial infarction. BACKGROUND: The recent randomized, controlled Survival and Ventricular Enlargement (SAVE) trial showed that captopril therapy improves survival in survivors of myocardial infarction with an ejection fraction < or = 40%. The present ancillary study was designed to determine how the costs required to achieve this increase in survival compared with those of other medical interventions. METHODS: We developed a decision-analytic model to assess the cost-effectiveness of captopril therapy in 50- to 80-year old survivors of myocardial infarction with an ejection fraction < or = 40%. Data on costs, utilities (health-related quality of life weights) and 4-year survival were obtained directly from the SAVE trial, and long-term survival was estimated using a Markov model. In one set of analyses, we assumed that the survival benefit associated with captopril therapy would persist beyond 4 years (persistent-benefit analyses), whereas in another set we assumed that captopril therapy incurred costs but no survival benefit beyond 4 years (limited-benefit analyses). RESULTS: In the limited-benefit analyses, the incremental cost-effectiveness of captopril therapy ranged from $3,600/quality-adjusted life-year for 80-year old patients to $60,800/quality-adjusted life-year for 50-year old patients. In the persistent-benefit analyses, incremental cost-effectiveness ratios ranged from $3,700 to $10,400/quality-adjusted life-year, depending on age. The outcome was generally not sensitive to changes in estimates of variables when they were varied individually over wide ranges. In a "worst-case" analysis, incremental cost-effectiveness ratios for captopril therapy remained favorable ($8,700 to $29,200/quality-adjusted life-year) for 60- to 80-year old patients but were higher ($217,600/quality-adjusted life-year) for 50-year old patients. CONCLUSIONS: We conclude that the cost-effectiveness of captopril therapy for 50- to 80-year old survivors of myocardial infarction with a low ejection fraction compares favorably with other interventions for survivors of myocardial infarction.

Aged

Postmyocardial infarction patients: experience from the SAVE trial.

Improving patient survival is the ultimate goal after acute myocardial infarction. Although thrombolytics, aspirin, and beta-blockers have greatly decreased mortality, structural changes such as ventricular dilatation evolving within the myocardium during and after acute myocardial infarction indicate a poor prognosis. The Survival and Ventricular Enlargement trial demonstrated that when administered 3 to 16 days after acute myocardial infarction in selected patients, captopril, the angiotensin-converting enzyme inhibitor, reduces ventricular dilatation, prevents the development of congestive heart failure, and reduces morbidity and mortality. This paper reviews results of that trial and presents guidelines for effective captopril dosage after acute myocardial infarction.

Captopril

Quantitative two-dimensional echocardiographic measurements are major predictors of adverse cardiovascular events after acute myocardial infarction. The protective effects of captopril.

BACKGROUND: Left ventricular enlargement after myocardial infarction increases the likelihood of an adverse outcome. In an echocardiographic substudy of the Survival and Ventricular Enlargement (SAVE) Trial, we assessed whether captopril would attenuate progressive left ventricular enlargement in patients with left ventricular dysfunction after acute myocardial infarction and, if so, whether this would be associated with improved clinical outcome. METHODS AND RESULTS: Two-dimensional transthoracic echocardiograms were obtained in 512 patients at a mean of 11.1 +/- 3.2 days after infarction and were repeated at 1 year in 420 survivors. Left ventricular size was assessed as left ventricular cavity areas at end diastole and end systole and left ventricular function as percent change in cavity area from end diastole to end systole. Patients were randomly assigned to placebo or captopril, and the incidence of adverse cardiovascular events consisting of cardiovascular death, heart failure requiring either hospitalization or open-label angiotensin-converting enzyme inhibitor therapy, and recurrent infarction were determined over a follow-up period averaging 3.0 +/- 0.6 years. Irrespective of treatment assignment, baseline left ventricular systolic area and percent change in area were strong predictors of cardiovascular mortality and adverse cardiovascular events. At 1 year, left ventricular end-diastolic and end-systolic areas were larger in the placebo than in the captopril group (P = .038, P = .015, respectively), and percent change in cavity area was greater in the captopril group (P = .005). One hundred eleven of the 420 1-year survivors with 1-year echo measurements (26.4%) experienced a major adverse cardiovascular event, and these patients had more than a threefold greater increase in left ventricular cavity areas than those with an uncomplicated course. Sixty-nine patients with adverse cardiovascular events were in the placebo group compared with 42 patients in the captopril-treated group (a risk reduction of 35%, P = .010). CONCLUSIONS: Two-dimensional echocardiography provides important and independent prognostic information in patients after infarction. Left ventricular enlargement and function after infarction are associated with the development of adverse cardiac events. Attenuation of ventricular enlargement with captopril in these patients was associated with a reduction in adverse events. This study demonstrates the linkage between attenuation of left ventricular enlargement by captopril after infarction and improved clinical outcome.

Captopril

Effects of captopril on ischemic events after myocardial infarction. Results of the Survival and Ventricular Enlargement trial. SAVE Investigators.

BACKGROUND: In the Survival and Ventricular Enlargement (SAVE) trial, recurrent myocardial infarction (MI) was the most important predictor of a poor outcome and conferred a sevenfold increase in risk of death. The purpose of this study was to determine the predictors of recurrent MI in study participants and to examine the influence of the angiotensin-converting enzyme inhibitor captopril on this and other myocardial ischemic events. METHODS AND RESULTS: The 2231 patients had survived the acute phase of MI (3 to 16 days) and had a radionuclide ventricular ejection fraction < or = 40%. Patients were randomly assigned to receive double-blind treatment with either placebo or captopril and were followed for an average of 42 months. The influence of captopril on recurrent MI, cardiac revascularization procedures, and hospitalization with unstable angina was examined. The likelihood of recurrent MI was greater in patients with an MI or functional disability before the index infarction and higher systolic pressure (all P < .001) but was not influenced by baseline left ventricular ejection fraction. Therapy with captopril reduced the risk of development of recurrent MI by 25% (95% confidence intervals, 5% to 40%; P = .015) and the risk of death after recurrent MI by 32% (95% confidence intervals, 4% to 51%; P = .029). Captopril-assigned patients were also less likely to require cardiac revascularization procedures (P = .010), but hospitalization for unstable angina was unaltered. When all three of these major coronary ischemic events were considered together, captopril therapy reduced the risk (14% risk reduction; 95% confidence intervals, 0% to 26%; P = .047). CONCLUSIONS: In post-MI patients with asymptomatic left ventricular dysfunction, long-term administration of captopril reduced recurrence of MI and the need for cardiac revascularization but had no influence on the rate of hospitalization with a discharge diagnosis of unstable angina. The finding that the recurrence of MI was independent of left ventricular ejection fraction suggests that captopril could be useful in preventing recurrent MI in patients with more preserved left ventricular function. The need for cardiac revascularization was reduced in patients receiving long-term captopril therapy, suggesting either an anti-ischemic effect or the ability of the angiotensin-converting enzyme inhibitor to modify the atherosclerotic process in survivors of MI.

Angina, Unstable

Comparison of effects of propranolol versus pindolol on sinus rate and pacing frequency in sick sinus syndrome.

Beta blockers in patients with sick sinus syndrome (SSS) may prevent supraventricular arrhythmias, systemic hypertension and myocardial ischemia, but may cause excessive depression of sinus node function. In 8 patients with SSS and a permanent pacemaker, the effect of chronic oral pindolol on sinus rate and pacing frequency was compared with that of propranolol in a double-blind crossover trial. In all patients the pacemaker was programmed to a rate of < or = 50 beats/min. Holter monitors, obtained at baseline and on each drug, were used to calculate peak ambulatory sinus rate, number of paced beats per day, maximal number of paced beats per hour, and percentage of hours with paced beats. The peak sinus rate with pindolol therapy was 24% higher than with propranolol (p = 0.001). During pindolol therapy, the number of paced beats per day and maximal paced beats per hour were reduced 54% (p = 0.04) and 61% (p = 0.02), respectively, compared with propranolol. Patients with SSS who require beta-blocker therapy for tachycardia, systemic hypertension or angina pectoris may have less bradycardia when treated with pindolol rather than propranolol. Beta blockers like pindolol, which cause less sinus node depression, may obviate the need for prophylactic permanent pacemakers in patients with SSS, and may help to prevent chronotropic incompetence and pacemaker syndrome in patients already treated with a VVI device.

Administration, Oral

Ventricular remodeling after myocardial infarction.

Acute transmural myocardial infarction initiates a series of changes in left ventricular (LV) volume, regional function and geometry. This process, known as post-infarction LV remodeling, may continue for months or years following the initial ischemic event. To characterize the components of late ventricular remodeling, biplane left ventriculography was performed in 52 patients at 3 weeks and repeated at 1 year after first anterior myocardial infarction. Biplane circumference and contractile and noncontractile segment lengths were measured. Global geometry was evaluated by calculating a sphericity index and regional geometry was assessed by measurement of endocardial curvature. End-diastolic (ED) volume was increased at 3 weeks and enlarged further at one year. This late enlargement was accompanied by an increase in the length of the contractile segment and an increase in sphericity, whereas the length of the noncontractile segment decreased. Curvature analysis revealed that this late increase in sphericity resulted from flattening of regions of presumably high tension negative curvature at the infarct border zone and from less bulging of the infarcted anterior wall. Even in patients selected for late ventricular enlargement (change in ED volume > 20 ml, n = 19), this increase in volume resulted from both lengthening of the contractile segment and an increase in sphericity without a change in the noncontractile segment length. Thus, late ventricular enlargement after anterior myocardial infarction results from an increase in contractile segment length and a change in ventricular geometry and is not a result of progressive infarct expansion.

Adult

Left ventricular hypertrophy in post-myocardial infarction left ventricular remodelling and in hypertension; similarities and contrasts.

Hypertensive left ventricular (LV) hypertrophy and post-myocardial infarction (MI) LV remodelling account for most of the clinically significant cases of LV hypertrophy presenting to a clinician. The clinical outcome of patients with concentric LV hypertrophy is known to be poor. However, it has not been widely recognized that post-MI LV remodelling is also dependent on wall stress-driven segmental LV hypertrophy. This review focuses on the similarities shared by these two related processes. The results of large scale clinical trials directed at these two processes is also discussed.

Animals

Development and prevention of congestive heart failure following myocardial infarction.

Ischemic heart disease is the major etiology for the development of congestive heart failure. Patients with acute myocardial infarction have a greatly increased risk for mortality and for manifesting symptomatic heart failure. This risk is not a uniform one but is greatly augmented in patients with a more extensive infarction and, consequently, a more depressed global ventricular function. An important concept that was derived from studies in rats with myocardial infarction and has been confirmed in patients is that ventricular enlargement, which has been shown to be a marker for an adverse outcome, can be a progressive process that leads to further deterioration of ventricular performance. Both experimental and early clinical studies have indicated that chronic therapy with an angiotensin converting enzyme inhibitor may attenuate this progressive ventricular enlargement. More definitive clinical trials are currently under way to determine whether this form of therapy, which may diminish the extent of ventricular enlargement over time, will result in an improvement in survival and in the prevention of the development of congestive heart failure. The addition of this pharmacological therapy to that of the primary prevention of atherosclerosis and that of the limitation of infarct size should make a substantial impact on the reduction of the incidence of congestive heart failure.

Animals

Do the results of randomized clinical trials of cardiovascular drugs influence medical practice? The SAVE Investigators.

BACKGROUND: Medical practice patterns change in response to a variety of stimuli, one of which may be the publication of the results of randomized clinical trials. We assessed the temporal association between the publication of clinical trials on myocardial infarction and changes in treatment practices for this disorder. METHODS: We analyzed the use of aspirin before and after myocardial infarction and that of calcium antagonists after myocardial infarction in 2231 survivors of myocardial infarction enrolled in the Survival and Ventricular Enlargement (SAVE) study over a three-year period (from January 1987 through January 1990). The proportion of patients using these treatments was analyzed before and after the publication dates of three clinical trials: the Physicians' Health Study, published in January 1988, which supported the use of aspirin to prevent a first myocardial infarction; the Second International Study of Infarct Survival (ISIS-2), published in August 1988, which supported the use of aspirin after myocardial infarction; and the Multicenter Diltiazem Postinfarction Trial, published in August 1988, which reported a deleterious effect of diltiazem in some patients after myocardial infarction. RESULTS: The use of aspirin before myocardial infarction increased from 16.2 percent to 23.9 percent between January 1987 and January 1990 (P less than 0.001). Enrollment in the study after the publication of the Physicians' Health Study independently predicted aspirin use before myocardial infarction (odds ratio, 1.43; 95 percent confidence interval, 1.11 to 1.85). The use of aspirin after myocardial infarction increased from 38.8 percent to 71.9 percent (P less than 0.001) during the three-year study period. Enrollment in the study after the publication of ISIS-2 independently predicted the use of aspirin after myocardial infarction (odds ratio, 2.28; 95 percent confidence interval, 1.89 to 2.76). The use of calcium antagonists after myocardial infarction decreased from 57.1 percent to 33.1 percent (P less than 0.001) during the study period. Enrollment in the study after the publication of the Multicenter Diltiazem Postinfarction Trial independently predicted the use of calcium antagonists after myocardial infarction (odds ratio, 0.47; 95 percent confidence interval, 0.39 to 0.57). CONCLUSIONS: These observations suggest that randomized clinical trials have a measurable influence on medical practice patterns.

Adult

Left ventricular remodeling in the year after first anterior myocardial infarction: a quantitative analysis of contractile segment lengths and ventricular shape.

Infarct expansion after myocardial infarction results in early ventricular enlargement and distortion of ventricular geometry. To characterize the components of late volume enlargement, biplane left ventriculography was performed in 52 patients 3 weeks and 1 year after a first anterior myocardial infarction. Biplane diastolic circumference and contractile and noncontractile segment lengths were measured. Global geometry was evaluated by using a sphericity index (angiographic volume of the ventricle divided by the volume of a sphere with the same circumference). Regional geometry was assessed by measurement of endocardial curvature, an important determinant of wall tension. End-diastolic volume was enlarged at baseline and increased at 1 year (230 +/- 42 to 244 +/- 55 ml, p = 0.01) as a result of increases in contractile segment length (34 +/- 5 to 37 +/- 5 cm, p less than 0.001) and sphericity index (0.74 +/- 0.07 to 0.76 +/- 0.08, p less than 0.001), whereas the noncontractile segment length decreased (15 +/- 6 to 12 +/- 6 cm, p less than 0.005). Curvature analysis revealed a flattening of presumably high tension concavity at the anterobasal (-6.0 +/- 4.0 to -4.5 +/- 3.7, p less than 0.01) and inferior (-4.5 +/- 2.0 to -3.6 +/- 2.1, p less than 0.005) margins of the infarct and less bulging of the anterior wall (9.4 +/- 2.5 to 8.2 +/- 2.3, p less than 0.001). Patients selected for late enlargement (diastolic volume increase greater than 20 ml, n = 19) had an increase in sphericity (0.75 +/- 0.05 to 0.80 +/- 0.08, p less than 0.005) and in diastolic circumference (54 +/- 3 to 56 +/- 4 cm, p less than 0.001) secondary to elongation of the contractile segment (32 +/- 4 to 36 +/- 4 cm, p = 0.001) at 1 year. Thus, late ventricular enlargement after anterior infarction results from an increase in contractile segment length and a change in ventricular geometry and is not a result of progressive infarct expansion. In the group of patients at high risk for late ventricular enlargement because of persistent occlusion of the infarct-related vessel, captopril therapy attenuated late volume enlargement by preventing these changes in contractile segment length and chamber geometry.

Adult

Does dual chamber or atrial pacing prevent atrial fibrillation? The need for a randomized controlled trial.

Partially due to recent reports that cardiac antiarrhythmic therapy may have adverse effects on patient survival, clinicians have become more interested in the nonpharmacological prevention of atrial fibrillation. There is a large body of literature that suggests that the rate of development of atrial fibrillation in paced sick sinus syndrome patients is much lower in those patients who have received an atrial-based system, rather than a VVI system. However, all the published studies to date are retrospective, and fraught with potential bias favoring the AAI or DDD group. The authors strongly believe that the only way to determine if these suggestive but uncertain retrospective analyses are correct is to apply the same scientific rigor to this problem as has been applied to many other problems in cardiovascular medicine and perform a prospective randomized trial. A proposed trial design is discussed.

Atrial Fibrillation

Patency of the infarct-related coronary artery and ventricular geometry.

The pathogenesis of acute myocardial infarction (AMI) involves a sudden thrombotic occlusion of a coronary artery. Spontaneous or pharmacologic thrombolysis may lead to myocardial salvage if patency is achieved within a narrow time window. However, patients in whom thrombolysis occurs late seem to demonstrate improved left ventricular (LV) function and prognosis, which may be independent of myocardial salvage. Preservation of normal LV geometry by reducing expansion of the infarcted segment is a likely mechanism for this benefit. Infarct expansion is most pronounced in patients with anterior wall AMI who have a persistently occluded infarct-related vessel. This process of expansion leads to early increases in LV volume and distortions of LV contour (abnormal LV geometry). Patients whose infarct segment is largest, patients who have manifested infarct expansion, and patients with a persistently occluded infarct-related artery are at highest risk for progressive LV dilation. Experimental data support the concept that reperfusion of occluded vessels that occurs too late for myocardial salvage will preserve LV geometry by limiting infarct expansion. Prospective clinical trials should address whether there is a late, "second time window" during which infarct expansion and distortions of LV geometry may be reduced by (1) therapy with thrombolytic agents applied late after infarction, (2) late mechanical reperfusion with percutaneous transluminal coronary angioplasty (PTCA) or related methods, and (3) load-reducing agents to decrease remodeling, such as angiotensin-converting enzyme inhibitors or nitroglycerin.

Animals

Left ventricular remodeling after acute myocardial infarction: clinical course and beneficial effects of angiotensin-converting enzyme inhibition.

LV enlargement is an important determinant of survival after AMI. Pathophysiologic mechanisms leading to LV dilatation after an AMI include early thinning and stretching of the infarcted segment (e.g., infarct expansion) and hypertrophy of the noninfarcted myocardium. Such LV dilatation may adversely affect subsequent cardiac function, leading to heart failure and death. Experimental data in animals and preliminary studies in humans have demonstrated that early administration of captopril, an angiotensin-converting enzyme inhibitor, may limit infarct expansion and will attenuate progressive LV dilatation. This article discussed the clinical importance of the dilated left ventricle and reviewed advances and ongoing research in the use of angiotensin-converting enzyme inhibitors in the chronic phase after AMI.

Angiotensin-Converting Enzyme Inhibitors