The natural history of left ventricular thrombus in myocardial infarction: a rationale in support of masterly inactivity

Left ventricular thrombus and subsequent thromboembolism, comparison of anticoagulation, surgical removal, and antiplatelet agents

Left ventricular (LV) thrombus is one of the risk factors for systemic thromboembolism. The aims of this study were to compare the long-term clinical outcomes of LV thrombus using current therapeutics, anticoagulation, operative treatment, and antiplatelet agents and to identify independent predictors of systemic thromboembolism.

METHODS

We screened 86,374 patients for intracardiac thrombus in the electronic medical records and imaging databases. Records of 62 patients with LV thrombus, diagnosed between May 2003 to November 2011, were comprehensively reviewed regarding baseline characteristics, imaging data and thrombus outcomes, thromboembolic events and treatment complications by treatment group.

RESULTS

The majority (80.6%) had ischemic etiology. Systemic thromboembolism developed in 18 patients; 8 (45%) were post-treatment thromboembolisms while 10 events occurred before treatment began. No post-treatment thromboembolism occurred in the operative treatment group; in contrast, 7 post-treatment thromboembolisms occurred in anticoagulation group (17%) (Log rank p= 0.175). Independent predictors of post-treatment thromboembolism were dilated cardiomyopathy (HR 61.30, p= 0.001), previous cerebrovascular events (HR 7.06, p= 0.042), female gender (HR 7.11, p= 0.031), and echocardiographic left ventricular end-diastolic diameter (HR 1.15, p= 0.047).

CONCLUSIONS

In this study, the rate of post-treatment thromboembolism was not significantly different among the treatment groups; however, operative treatment tended towards less post-treatment thromboembolism than other treatment groups.

Left ventricular thrombus attenuation characterization in cardiac computed tomography angiography

BACKGROUND

Because of their similar visual appearance, differentiation of left ventricular thrombotic material and myocardial wall can be difficult in contrast-enhanced coronary computed tomography (CT) angiography.

OBJECTIVE

We identified typical thrombi attenuation of left ventricular thrombi with the use of CT measurement.

METHODS

Over a time period of 6 years, we retrospectively identified 31 patients who showed a left ventricular thrombus in CT angiography datasets. Patients underwent routine contrast cardiac CT to investigate coronary artery disease. CT attenuation of each thrombus was assessed in the 4-chamber view. CT densities were also determined in the ascending aorta, left ventricle, and myocardial wall both in the mid-septal and mid-lateral segments. The mean CT attenuation of thrombi and the difference between attenuation in thrombi, left ventricular cavity, and myocardial wall were determined. The ratio of attenuation values in thrombus versus aorta and myocardium versus aorta were also determined.

RESULTS

Mean (±SD) CT attenuation of all left ventricular thrombi in 31 patients was 43.2 ± 15.3 HU (range, 25-80 HU). Mean CT densities of septal and lateral myocardial wall were 102.9 ± 23.1 HU (range, 63-155 HU) and 99.3 ± 28.7 HU (range, 72-191 HU), respectively, and were thus significantly higher than the CT attenuation of thrombi (P < 0.001). A threshold of 65 HU yielded a sensitivity, specificity, and positive and negative predictive values of 94%, 97%, 94%, and 97%, respectively, to differentiate thrombus from the myocardial wall. The mean ratio between CT attenuation of thrombus and CT attenuation within the ascending aorta was 0.11 ± 0.05 (range, 0.04-0.23), which was significantly lower compared with the mean ratio between CT attenuation of the myocardial wall and the CT attenuation within the ascending aorta.

CONCLUSION

CT attenuation within left ventricular thrombi was significantly lower than myocardial attenuation in CT angiography datasets. Assessment of CT attenuation may contribute to the differentiation of thrombi.

LV thrombus detection by routine echocardiography: insights into performance characteristics using delayed enhancement CMR

OBJECTIVES

This study sought to evaluate performance characteristics of routine echo for left ventricular thrombus (LVT).

BACKGROUND

Although the utility of dedicated echocardiography (echo) for LVT is established, echo is widely used as a general test for which LVT is rarely the primary indication. We used delayed-enhancement cardiac magnetic resonance (DE-CMR) as a reference to evaluate LVT detection by routine echo.

METHODS

Dedicated LVT assessment using DE-CMR was prospectively performed in patients with left ventricular systolic dysfunction. Echoes were done as part of routine clinical care. Echo and CMR were independently read for LVT and related indexes of LVT size, shape, and image quality/diagnostic confidence. Follow-up was done for embolic events and pathology validation of LVT.

RESULTS

In this study, 243 patients had routine clinical echo and dedicated CMR within 1 week without intervening events. Follow-up supported DE-CMR as a reference standard, with >5-fold difference in endpoints between patients with versus without LVT by DE-CMR (p = 0.02). LVT prevalence was 10% by DE-CMR. Echo contrast was used in 4% of patients. Echo sensitivity and specificity were 33% and 91%, with positive and negative predictive values of 29% and 93%. Among patients with possible LVT as the clinical indication for echo, sensitivity and positive predictive value were markedly higher (60%, 75%). Regarding sensitivity, echo performance related to LVT morphology and mirrored cine-CMR, with protuberant thrombus typically missed when small (p ≤ 0.02). There was also a strong trend to miss mural thrombus irrespective of size (p = 0.06). Concerning positive predictive value, echo performance related to image quality, with lower diagnostic confidence scores for echoes read positive for LVT in discordance with DE-CMR compared with echoes concordant with DE-CMR (p < 0.02).

CONCLUSIONS

Routine echo with rare contrast use can yield misleading results concerning LVT. Echo performance is improved when large protuberant thrombus is present and when the clinical indication is specifically for LVT assessment.

Silent ST segment elevation myocardial infarction with multi-segmental renal infarction: an unusual presentation

A 36-year-old diabetic man came to our institution presenting with constant left flank pain. Left renal embolic infarction was found by abdominal computed tomography. Silent ST segment elevation myocardial infarction was noted on 12-lead electrocardiogram. Emergent coronary angiography revealed large thrombus burdens with complete occlusion at the left anterior descending artery ostium, which may be the embolic origin. Silent ST segment elevation myocardial infarction with acute flank pain and multiple segmental renal infarction is an unusual presentation. High vigilance may prevent delay of the "golden hour" to treat acute myocardial infarction.

Detection of left ventricular thrombus by delayed-enhancement cardiovascular magnetic resonance prevalence and markers in patients with systolic dysfunction

OBJECTIVES

This study sought to assess the prevalence and markers of left ventricular (LV) thrombus among patients with systolic dysfunction.

BACKGROUND

Prior studies have yielded discordant findings regarding prevalence and markers of LV thrombus. Delayed-enhancement cardiovascular magnetic resonance (DE-CMR) identifies thrombus on the basis of tissue characteristics rather than just anatomical appearance and is potentially highly accurate.

METHODS

Prevalence of thrombus by DE-CMR was determined in 784 consecutive patients with systolic dysfunction (left ventricular ejection fraction [LVEF] <50%) imaged between July 2002 and July 2004. Patients were recruited from 2 separate institutions: a tertiary-care referral center and an outpatient clinic. Comparison to cine-cardiovascular magnetic resonance (CMR) was performed. Follow-up was undertaken for thrombus verification via pathology evaluation or documented embolic event within 6 months after CMR. Clinical and imaging parameters were assessed to determine risk factors for thrombus.

RESULTS

Among this at-risk population (age 60 +/- 14 years; LVEF 32 +/- 11%), DE-CMR detected thrombus in 7% (55 patients) and cine-CMR in 4.7% (37 patients, p < 0.005). Follow-up was consistent with DE-CMR as a better reference standard than cine-CMR, including 100% detection among 5 patients with thrombus verified by pathology (cine-CMR, 40% detection), and logistic regression analysis testing the contributions of DE-CMR and cine-CMR simultaneously, which showed that only the presence of thrombus by DE-CMR was associated with follow-up end points (p < 0.005). Cine-CMR generally missed small intracavitary and small or large mural thrombus. In addition to traditional indices such as low LVEF and ischemic cardiomyopathy, multivariable analysis showed that increased myocardial scarring, an additional parameter available from DE-CMR, was an independent risk factor for thrombus.

CONCLUSIONS

In a broad cross section of patients with systolic dysfunction, thrombus prevalence was 7% by DE-CMR and included small intracavitary and small or large mural thrombus missed by cine-CMR. Prevalence increased with worse LVEF, ischemic etiology, and increased myocardial scarring.

Cardiovascular manifestations of hypereosinophilic syndromes

The hypereosinophilic syndromes (HESs) are characterized by persistent marked eosinophilia (>1500 eosinophils/mm(3)), the absence of a primary cause of eosinophilia (such as parasitic or allergic disease), and evidence of eosinophil-mediated end organ damage. Cardiovascular complications of HES are a major source of morbidity and mortality in these disorders. The most characteristic cardiovascular abnormality in HES is endomyocardial fibrosis. Patients who have an HES also may develop thrombosis, particularly in the cardiac ventricles, but also occasionally in deep veins. Because of the rarity of these disorders, specific guidelines for the management of the cardiac and thrombotic complications of HES are lacking. This article reviews the diagnosis and management of the cardiovascular manifestations of HES.

Peak C-reactive protein concentration correlates with left ventricular thrombus formation diagnosed by contrast echocardiographic left ventricular opacification in patients with a first anterior acute myocardial infarction

BACKGROUND

Wall motion abnormality in the apical legion of the left ventricle (LV) with stagnant flow alone is not sufficient to identify patients at high risk for LV thrombus formation among those with first anterior acute myocardial infarction (AMI). The aim of this study was to identify the determinants of LV thrombus formation using contrast echocardiography.

METHODS AND RESULTS

In 75 patients with first anterior AMI, standard and contrast echocardiography was performed to detect LV thrombus. Although LV thrombus was found in 10 patients (13%) using standard echocardiography, it was found in 15 patients (20%) using contrast echocardiography. Apical stagnant flow was observed in 14 patients (93%) with LV thrombus. In addition, patients with LV thrombus had a higher peak C-reactive protein (CRP) concentration (18.2+/-4.3 vs 7.9+/-5.5 mg/dl, p<0.0001). In multivariate analysis, only peak CRP concentration was identified as an independent predictor of LV thrombus (p=0.02, odds ratio: 1.400, confidence interval: 1.040-1.884). The receiver-operating characteristics (ROC) analysis revealed the best cutoff value of a peak CRP concentration >10.7 mg/dl to identify patients with LV thrombus (sensivity 0.93, specificity 0.75, area under ROC curve 0.91).

CONCLUSIONS

The peak CRP concentration is a useful marker of patients with first anterior AMI who are at high risk for LV thrombus.

Carotid atherosclerotic plaque instability in patients with acute myocardial infarction

The instability of atherosclerotic plaque is partly determined by local factors, but systemic factors such as infection, inflammation, autoimmunity or genes might also be important. We aimed to analyze whether patients with acute myocardial infarction (AMI) might have a higher proportion of unstable plaques in the carotid arteries compared with patients who had had no acute coronary events.

METHODS

Sixty-nine consecutive patients with AMI (Group 1) and 95 patients without acute coronary events (Group 2) had carotid artery duplex ultrasounds. Carotid atherosclerosis was quantified by number of plaques in the two carotid arteries, intimal media thickening and degree of maximal stenosis. According to their morphology, plaques were divided into stable (fibrocalcific) and unstable (soft and/or not homogeneous).

RESULTS

The two groups did not differ as regards age (66+/-8 vs. 68+/-19; p=0.3), female sex (13% vs. 21%; p=0.3), mean number of carotid plaques (2.8+/-1 vs. 2.5+/-2; p=0.2), degree of stenosis (59+/-2% vs. 36+/-1%; p=0.2) or intimal media thickening (1.04+/-0.2 vs. 1.06+/-0.2; p=0.8). However, Group 1 pts more frequently had unstable carotid plaques compared with Group 2 (43% vs. 15%; p=0.004), and had a greater number of unstable carotid plaques (0.51+/-0.6 vs. 0.16+/-0.4: p<0.0001) and a higher ratio of unstable to stable plaque (19% vs. 8%; p=0.005). In the overall population, logistic regression analysis showed that after adjustment for degree of maximal stenosis, the presence of coronary artery event (AMI pts) predicted the presence of unstable carotid plaque (OR: 4.3 95% CI: 2.0-9.2; p=0.0002).

CONCLUSION

Patients with unstable coronary artery disease expressed clinically as AMI, frequently had unstable atherosclerotic plaques in other arterial sites such as carotid arteries. This finding supports the hypothesis that plaque instability might reflect a systemic process.

Part I: use of echocardiography in the evaluation of patients with suspected cardioembolic stroke

One-sixth of all ischemic strokes are a result of embolization from the heart. Echocardiography serves as the cornerstone in evaluating patients who may have had a cardioembolic stroke. This article is the first of a two-part review series focusing on the role of echocardiography in the diagnosis and treatment of cardioembolic stroke. Specifically, this section will focus on nonrheumatic atrial fibrillation as well as cardiovascular masses as potential embolic sources.

Risk factors for intracardiac thrombus in patients with recent ischaemic cerebrovascular events

BACKGROUND

Intracardiac thrombus is a common cause of cardiogenic cerebral ischaemia. Stroke recurrence is high, but thrombus detection with therapeutic intervention can reduce the risk. Accurate detection requires transoesophageal echocardiography (TOE), which is semi-invasive and costly.

OBJECTIVE

To identify risk factors for cardiac thrombus, enabling selection of patients for TOE and initiation of measures to prevent the formation of cardiac thrombus.

METHODS

151 consecutive patients with ischaemic stroke or transient ischaemic attacks (mean age 62 years) underwent TOE for intracardiac thrombus detection within one week of a qualifying event.

RESULTS

Intracardiac thrombus was found in 26% of the patients (70% in the left atrial appendage). Multivariate analysis indicated the following clinical correlates: large stroke, odds ratio (OR) = 2.8 (95% confidence interval, 1.2 to 6.4); symptomatic coronary artery disease, OR = 3.0 (1.2 to 7.4); and ECG evidence of ischaemia, OR = 2.8 (1.1 to 7.7). Neither carotid stenosis >70%, nor stroke location correlated with the presence of thrombus.

CONCLUSIONS

Clinical factors correlate with and appear to be risk factors for cardiac thrombus in patients with recent cerebral ischaemia. These may be used to select appropriate patients for invasive and costly TOE investigation, irrespective of the presence of significant carotid stenosis (>/=70%) or stroke location.

Association Between Serum C-Reactive Protein Elevation and Left Ventricular Thrombus Formation After First Anterior Myocardial Infarction

STUDY OBJECTIVES

Most left ventricular (LV) thrombi that occur after acute myocardial infarction (AMI) are formed within 2 weeks, when inflammatory cells have infiltrated into the necrotic myocardium. Inflammatory changes on the endocardial surface may induce platelet deposition and fibrin net formation through interaction with proinflammatory cytokines. We sought to determine the significance of the inflammatory response reflected by serum C-reactive protein (CRP) elevation in LV thrombus formation after AMI.

DESIGN

We examined 160 patients with first anterior AMI. Peak serum creatine kinase (CK) and CRP levels were determined by serial measurements. Echocardiography was performed 10 to 14 days after the onset. We assessed the association between the elevation of serum CRP levels and LV thrombus formation after AMI.

RESULTS

LV thrombus was observed in 13 patients (8%). There was no difference in age, sex, coronary risk factors, preinfarction angina, use of revascularization therapy and anticoagulant therapy, platelet count, and fibrinogen level on hospital admission between the two groups. The mean (+/- SD) peak serum CRP level was markedly increased in patients with LV thrombus compared to those without (18.0 +/- 12.6 vs 9.4 +/- 8.1 mg/dL; p = 0.001), despite their having similar peak CK levels. Multivariate analysis showed that a peak CRP level of > or =20 mg/dL was an independent predictor of thrombus formation (relative risk, 4.82; p = 0.037) among variables including older age (> or =60 years old), peak CK level (> or =3,000 IU/L), and peak WBC count (> or =12,000 cells/ microL).

CONCLUSION

A greater elevation of serum CRP level was associated with a higher incidence of LV thrombus after AMI, suggesting an important role of the inflammatory response in mural thrombus formation.

Doppler-derived mitral deceleration time as an early predictor of left ventricular thrombus after first anterior acute myocardial infarction

BACKGROUND

The relation between left ventricular (LV) diastolic function and LV thrombus has not yet been fully investigated. The aim of this study was to determine whether early assessment of Doppler-derived mitral deceleration time (DT), a measure of LV compliance and filling, may predict LV thrombus formation after acute myocardial infarction.

METHODS AND RESULTS

Two-dimensional and Doppler echocardiographic examinations were performed in 98 consecutive patients (aged 57 +/- 12 years; 8 women) with first acute myocardial infarction. The patients were studied within 24 hours and at days 3, 7, 15, and 30 after arrival to the coronary care unit. Mitral flow velocities were obtained from the apical 4-chamber view with pulsed Doppler. LV thrombus was detected in 20 of 98 patients. Patients were divided into 2 groups according to LV thrombus formation: group 1 (n = 20) with thrombus and group 2 (n = 78) without thrombus. Mitral E-wave DT was significantly shorter in group 1 than group 2 (134 ms vs 175 ms; P <.001). Patients in group 1 had significantly larger LV end-diastolic and end-systolic volumes and a higher wall motion score index than patients in group 2 (133 +/- 39 mL vs 112 +/- 41 mL, P =.03; 83 +/- 34 mL vs 59 +/- 30 mL, P =.003; and 1.8 +/- 0.3 mL vs 1.5 +/- 0.3 mL, P =.007, respectively). The LV ejection fraction was significantly lower in group 1 than in group 2 (39% +/- 13% vs 48% +/- 12%; P =.004). In a multivariate regression analysis, mitral E-wave DT was identified as an independent variable related to development of LV thrombus (P =.04).

CONCLUSIONS

Doppler-derived mitral DT is superior to conventional clinical and 2-dimensional echocardiographic assessment in estimating the risk of left ventricular thrombosis after myocardial infarction.

Predictors of left ventricular thrombus formation in patients with anterior myocardial infarction: role of activated protein C resistance

BACKGROUND

Left ventricular mural thrombus formation is a well-recognised consequence of acute anterior myocardial infarction. The vast majority of left ventricular thromboses occur in patients with anterior myocardial infarction and depressed left ventricular function.

OBJECTIVE

To evaluate the factors predicting left ventricular thrombus formation in patients similar for left ventricular function and left ventricular score indexes.

METHODS

We evaluated 45 consecutive patients who met the inclusion criteria of anterior myocardial infarction resulting in apical, anterior or septal asynergy (akinesia, dyskinesia), without non-Q-wave myocardial infarction, dilated cardiomyopathy, or renal or hepatic dysfunction. Patients were divided into two groups: group I with, and group II without, left ventricular mural thrombus. The groups were compared for clinical, echocardiographic and hematologic parameters (activated protein C resistance (APC-R), protein S and antithrombin III).

RESULTS

Smoking and ACP-R were significantly greater in group I than in group II (P < 0.05 and P < 0.005 respectively). Multivariate regression analysis showed that APC-R was an independent risk factor for left ventricular thrombus formation in the patient group selected. Antithrombin III and protein S concentrations were not statistically different between two groups. All other clinical and echocardiographic characteristics of the patients were similar in both groups.

CONCLUSION

APC-R is an independent risk factor for left ventricular thrombosis in patients with anterior myocardial infarction resulting in septal or anterior and apical akinesia or dyskinesia.

Echocardiographic Recognition of Left Ventricular Mural Thrombus

Left ventricular (LV) mural thrombus is a well recognized complication of acute myocardial infarction. In survivors of infarction, its incidence is influenced by the location and magnitude of infarction: it occurs often in patients with large anterior Q wave infarctions, particularly in the presence of LV apical akinesis or dyskinesis. Although radionuclide imaging with indium-111-labeled platelets, computed tomography, and magnetic resonance imaging may be used to identify LV mural thrombus, two-dimensional echocardiography is the technique of choice for assessing its presence, shape, and size, and recent technical advances in echocardiographic methodology, such as high-frequency, short-focal-length transducers, have improved the echocardiographic assessment of LV mural thrombus. In the patient in whom a mural thrombus is identified, acute and chronic anticoagulation (with heparin and warfarin, respectively) is indicated: first, to prevent further thrombus formation and, second, to reduce the incidence of systemic embolization.

Long-term prospective assessment of left ventricular thrombus in anterior wall acute myocardial infarction and implications for a rational approach to embolic risk

To prospectively assess the predictive value of left ventricular (LV) thrombus anatomy for defining the embolic risk after acute myocardial infarction (AMI), 2 comparable groups of patients with a first anterior AMI (group A, 97 thrombolysed patients; group B, 125 patients untreated with antithrombotic drugs [total 222]) underwent prospective serial echocardiography (follow-up 39 +/- 13 months) at different time periods. LV thrombi were detected in 26 patients in group A (27%) and in 71 in group B (57%; p <0.005). Embolism occurred in 12 patients (5.4%; 1 in group A [1%] vs 11% in group B [9%], p < 0.04). At multivariate analysis, thrombus morphologic changes were the most powerful predictor of embolism (p <0.001), followed by protruding shape (p <0.01) and mobility (p <0.02). In patients untreated with thrombolysis, a higher occurrence of thrombus morphologic changes (48% vs 8%, p <0.002) and protruding shape (69% vs 31%, p <0.002) were observed, whereas thrombus mobility was similar in the 2 groups (18% vs 8%, p = NS). Thrombus resolution occurred more frequently in thrombolysed patients (85% vs 56%, p <0.002). Thus, after anterior AMI, changes in LV thrombus anatomy frequently occur and appear the most powerful predictor of embolization. A minor prevalence of thrombus, a more favorable thrombus anatomy, and a higher resolution rate may contribute to reduce embolic risk after thrombolysis.

Role of echocardiography in systemic arterial embolism. A review with recommendations

The ability of echocardiography to diagnose sources of embolism and the role of the examination in the prediction of thromboembolism are reviewed. In addition, the yield of transthoracic (TTE) and transoesophageal echocardiography (TEE) is analysed in patients with suspected embolism and guidelines are proposed for performing echocardiography in this setting. In general, echocardiography is reliable for diagnosing sources of embolism and this applies in particular to TEE in the case of atrial, valvular, and aortic abnormalities. However, the method is useful for predicting embolism in a few cases only. There is a substantial risk in the event of mobile or protruding thrombi, but screening for these and other markers of thromboembolism seems to be unproductive in most groups of risk patients. Yet, in the presence of atrial fibrillation, echocardiography may be helpful in defining patients with an otherwise normal heart and low risk of embolism--and in defining the relatively rare patient with a clinically low-risk profile but moderate-to-severe left ventricular systolic dysfunction and a high risk of embolism. TEE-guided conversion of atrial fibrillation without weeks of preceding anticoagulation may prove useful, after further investigation. The risk of embolism in relation to the size and mobility of valvular vegetations has remained controversial. In patients with suspected recent embolism, TTE results in less than 5% new therapeutic consequences. In those with a normal TTE, the yield of TEE seems to be equally low. We therefore recommend a selective strategy: TTE and TEE can be omitted when a cardiac source of embolism appears from the clinical setting and in most patients with an obvious predisposition to cerebrovascular disease. However, in the latter cases TTE should be performed if indicated by the clinical situation, e.g. in the presence of fever and murmur. TTE is also recommended when there are no obvious markers of primary vascular disease. To preclude very rare sources of embolism (e.g. atrial thrombi despite sinus rhythm), supplementary TEE is recommended in younger patients in whom primary vascular disease is very unlikely. The diagnosis by TEE of common conditions such as atrial septal aneurysms and patent foramen ovale cannot, however, be taken as proof of the mechanism of a systemic arterial occlusive event; thus it is difficult to change therapy on the basis of such diagnoses.

Predischarge two-dimensional echocardiographic evaluation of left ventricular thrombosis after acute myocardial infarction in the GISSI-3 study

Left ventricular (LV) thrombosis can be found in patients with acute myocardial infarction (AMI). No wide multicenter trial on AMI has provided information about LV thrombosis until now. The protocol of the GISSI-3 study included the search for the presence of LV thrombosis in patients from 200 coronary care units that did not specifically focus on LV thrombosis. We examined the GISSI-3 database results related to 8,326 patients at low to medium risk for LV thrombi in which a predischarge echocardiogram (9 +/- 5 days) was available. LV thrombosis was found in 427 patients (5.1%): 292 of 2,544 patients (11.5%) with anterior AMI and in 135 of 5,782 patients (2.3%) with AMI in other sites (p <0.0001). The incidence of LV thrombosis was higher in patients with ejection fraction < or = 40% (151 of 1,432 [10.5%] vs 276 of 6,894 [4%]; p <0.0001) both in the total population and in the subgroup with anterior AMI (106 of 597 [17.8%] vs 186 of 1,947 [9.6%]; p <0.0001). Multivariate analysis showed that only the Killip class > I and early intravenous beta-blocker administration were independently associated with higher LV thrombosis risk in the subgroup of patients with anterior AMI (odds ratio 1.75, 95% confidence interval 1.28 to 2.39; odds ratio 1.32, 95% confidence interval 1.02 to 1.72, respectively). In patients with anterior AMI, oral beta-blocker therapy given or not given after early intravenous beta-blocker administration does not influence the occurrence of LV thrombosis. The rate of LV thrombosis was similar in patients treated or not treated with nitrates and lisinopril both in the total population and in patients with anterior and nonanterior AMI. In conclusion, in the GISSI-3 population at low to medium risk for LV thrombi, the highest rate of occurrence of LV thrombosis was found among patients with anterior AMI and an ejection fraction < 40%. Killip class > I and the early intravenous beta-blocker administration were the only variables independently associated with a higher predischarge incidence of LV thrombosis after anterior AMI.

Risk factors for in-hospital nonhemorrhagic stroke in patients with acute myocardial infarction treated with thrombolysis: results from GUSTO-I

BACKGROUND

Nonhemorrhagic stroke occurs in 0.1% to 1.3% of patients with acute myocardial infarction who are treated with thrombolysis, with substantial associated mortality and morbidity. Little is known about the risk factors for its occurrence.

METHODS AND RESULTS

We studied the 247 patients with nonhemorrhagic stroke who were randomly assigned to one of four thrombolytic regimens within 6 hours of symptom onset in the GUSTO-I trial. We assessed the univariable and multivariable baseline risk factors for nonhemorrhagic stroke and created a scoring nomogram from the baseline multivariable modeling. We used time-dependent Cox modeling to determine multivariable in-hospital predictors of nonhemorrhagic stroke. Baseline and in-hospital predictors were then combined to determine the overall predictors of nonhemorrhagic stroke. Of the 247 patients, 42 (17%) died and another 98 (40%) were disabled by 30-day follow-up. Older age was the most important baseline clinical predictor of nonhemorrhagic stroke, followed by higher heart rate, history of stroke or transient ischemic attack, diabetes, previous angina, and history of hypertension. These factors remained statistically significant predictors in the combined model, along with worse Killip class, coronary angiography, bypass surgery, and atrial fibrillation/flutter.

CONCLUSIONS

Nonhemorrhagic stroke is a serious event in patients with acute myocardial infarction who are treated with thrombolytic, antithrombin, and antiplatelet therapy. We developed a simple nomogram that can predict the risk of nonhemorrhagic stroke on the basis of baseline clinical characteristics. Prophylactic anticoagulation may be an important treatment strategy for patients with high probability for nonhemorrhagic stroke, but further study is needed.

Incidence and natural history of left ventricular thrombus following anterior wall acute myocardial infarction

Previous studies have reported left ventricular (LV) thrombus in 20% to 56% of patients after anterior wall acute myocardial infarction (AMI). The Healing and Early Afterload Reducing Therapy (HEART) study was a prospective study comparing effects of early (24 hours) or delayed (14 days) initiation of ramipril, an angiotensin-converting enzyme inhibitor, on LV function after anterior wall AMI. This ancillary study assessed prevalence of LV thrombus. Two-dimensional echocardiography was performed on days 1, 14, and 90 after myocardial infarction. The cohort consisted of 309 patients. Q-wave anterior wall AMI occurred in 78%; 87% received reperfusion therapy. The prevalence of LV thrombus was 2 of 309 (0.6%) at day 1, 11 of 295 (3.7%) at day 14, and 7 of 283 (2.5%) at day 90. One patient had thrombus at 2 examinations. The day 1 echocardiogram was not correlated with thrombus development. LV size increased more in patients with thrombus than in those without thrombus. Patients with thrombus had more wall motion abnormality after day 1 than patients without thrombus (p = 0.03). Thus, the current prevalence of LV thrombus in anterior wall AMI is lower than previously reported, possibly due to changes in AMI management. Preservation of LV function is likely to be an important mechanism. Most thrombi are seen by 2 weeks after AMI. Resolution documented by echocardiography is frequent.

Long term follow up of patients with anterior myocardial infarction complicated by left ventricular thrombus in the thrombolytic era

OBJECTIVES

To examine the appearance and resolution of left ventricular thrombi and to study the relation between thrombus and mortality during long term follow up after anterior myocardial infarction.

DESIGN

Ninety nine consecutive patients were prospectively studied until the last included patient had been followed for one year. Streptokinase and aspirin were used routinely, anticoagulants only after a decision by the attending physician. Echocardiography was performed within 3 d of admission, before discharge, and after one, three, and 12 months.

SETTING

Umeå University Hospital, a teaching hospital in Northern Sweden.

MAIN OUTCOME MEASURES

Left ventricular thrombus, segmental myocardial function, and mortality during follow up.

RESULTS

Thirty patients (30%) had a thrombus on discharge. One month, three months, and 12 months after hospital discharge, the thrombus had resolved in 81%, 84%, and 90% of the patients, respectively. The proportion of resolved thrombi at one month was high irrespective of whether anticoagulants were given (10/11, 91%) or not (12/16, 75%), P = 0.4. New thrombi appeared in 12 patients after discharge and resolution and reapperance of thrombi continued during the follow up period. Patients who developed a thrombus during the hospital stay (n = 44, 44%) had more extensive myocardial dysfunction on discharge (P < 0.001) and significantly higher mortality during the follow up period than those without a thrombus (23% v 7%, P < 0.01).

CONCLUSIONS

With routine thrombolytic and aspirin treatment of anterior myocardial infarction, left ventricular thrombi usually resolve during the first month after hospital discharge. Appearance and resolution of thrombi continue, however, in a significant proportion of the patients during long term follow up. A left ventricular thrombus during the initial hospital stay is associated with high long term mortality.

Left ventricular mural thrombus after acute myocardial infarction

Left ventricular mural thrombus is a well-recognized complication of acute myocardial infarction. In survivors of infarction, the incidence with which mural thrombus occurs is influenced by the location and magnitude of infarction, so that it occurs commonly in those with large anterior Q-wave infarctions, particularly in the presence of a left ventricular aneurysm. Echocardiography, radionuclide imaging with indium-111 labeled platelets, computerized tomography, and magnetic resonance imaging may be used to identify a left ventricular mural thrombus. Acute and chronic anticoagulation with heparin and warfarin, respectively, is given to prevent further thrombus formation and to reduce the incidence of systemic embolization.

In consecutive patients hospitalized with acute myocardial infarction, infarct location according to routine electrocardiogram is of minor importance for the outcome

Most studies have suggested that patients with anterior myocardial infarction have an adverse prognosis compared with patients with inferior infarction. The objective of this study was to compare the mortality and morbidity in anterior versus inferior acute myocardial infarction (AMI) during 1 year in a consecutive series of patients hospitalized with AMI. All patients fulfilling the criteria for AMI who were admitted to a single hospital during 21 months (n = 921) participated in the study. Patients with anterior infarction (n = 312) had a 1-year mortality rate of 26% versus a rate of 24% for patients with inferior infarction (n = 269) (p > 0.2). The corresponding figures for patients with no previous infarction who developed Q waves were 27 and 21%, respectively (p > 0.2). Reinfarction, thromboembolic events, and other aspects of morbidity during long-term follow-up appeared with similar frequency in the two groups. Thus, in a nonselected group of patients admitted to a single hospital because of AMI, the prognosis was found to be similar among patients with inferior and those with anterior infarction. In the subset of patients with a first myocardial infarction who developed Q waves, there was a trend indicating higher mortality in anterior infarction.

Left ventricular thrombosis after anterior myocardial infarction with and without thrombolytic treatment

OBJECTIVES

To examine the incidence of left ventricular thrombus in patients with anterior myocardial infarction, with and without streptokinase treatment. To identify predictors of thrombus development.

DESIGN

Consecutive patients prospectively studied during the hospitalized period. Echocardiography was performed within 3 days of admission and before discharge.

SETTING

Umeå University Hospital, a teaching hospital in Northern Sweden.

SUBJECTS

Ninety-nine patients with anterior myocardial infarction of whom 74 were treated with streptokinase.

MAIN OUTCOME MEASURES

Left ventricular thrombus and left ventricular segmental myocardial function.

RESULTS

During the hospital stay, a thrombus developed in 46% (95% confidence interval [CI], 35-57%) of the patients in the thrombolysis group and in 40% (95% CI, 21-59%) of the patients in the non-thrombolysis group. No difference in left ventricular segmental myocardial function was found between the thrombolysis and non-thrombolysis groups at hospital discharge. No embolic events were observed. The occurrence of a left ventricular thrombus at hospital discharge was significantly associated with previous myocardial infarction, peak enzyme levels, left ventricular global and segmental dysfunction and an increased dose of peroral diuretics or use of parenteral diuretics. In a multiple logistic regression model, left ventricular segmental dysfunction was the most important predictor of left ventricular thrombus.

CONCLUSION

Thrombolytic treatment with streptokinase does not prevent the development of a left ventricular thrombus but the risk of embolic complications is low. The left ventricular segmental myocardial score can be used to assess the risk of thrombus development, also, after thrombolysis.

Efficacy of high dose intravenous heparin for treatment of left ventricular thrombi with high embolic risk

OBJECTIVES

This study was performed to assess the efficacy of high dose intravenous heparin to treat mobile or protruding left ventricular thrombi as detected by serial echocardiography.

BACKGROUND

The presence of mobile and protruding left ventricular thrombi greatly increases the risk of arterial embolization, yet optimal therapy, be it thrombolysis, anticoagulation or surgical removal, has not been defined.

METHODS

Full dose heparin, 31,291 +/- 7,980 (mean +/- SD) IU/day, to prolong partial thromboplastin time to at least twice normal, was administered intravenously to 23 consecutive patients with 25 mobile and protruding thrombi. Patients were prospectively evaluated for hemorrhagic complications and embolic events during therapy. The presence or absence of thrombi and their size and characteristics were assessed by serial echocardiography.

RESULTS

In all 23 patients left ventricular thrombi decreased in size, with disappearance of the high risk features. The duration of high dose heparin infusion was 7 to 22 days (mean 14 +/- 4). Thrombus size was reduced from 3.9 +/- 2.6 to 0.16 +/- 0.38 cm2, and thrombus disappeared entirely in 19 (83%) of 23 patients. No embolic events were detected during treatment, and the only complication was an upper gastrointestinal hemorrhage that was successfully treated medically.

CONCLUSION

High dose intravenous heparin is a highly effective and safe treatment for completely resolving left ventricular thrombi with high risk features for embolization. Most such thrombi disappear completely within 1 to 3 weeks of this treatment without embolic or hemorrhagic complications.

Relation between myocardial infarct location and stroke

OBJECTIVES

We sought to compare the likelihood of stroke in patients with anterior versus nonanterior myocardial infarction.

BACKGROUND

The association between anterior infarction and left ventricular thrombus has led to the assumption that embolization from thrombi is an important cause of stroke in patients with anterior infarction. We hypothesized that if anterior infarction is a cause of left ventricular thrombi, the number of strokes should be disproportionately higher in patients with anterior than nonanterior infarction.

METHODS

We performed a retrospective analysis of 2,466 patients randomized from day 3 to day 15 after infarction as part of a multicenter placebo-controlled study of diltiazem to prevent cardiac death or myocardial infarction. Any acute focal cerebral disorder resulting in localizing findings characterized as a stroke or transient ischemic attack was considered an event.

RESULTS

Of 91 events during a follow-up period of 12 to 52 months, 23 (3.2%) occurred in 724 patients with an anterior and 68 (3.9%) in 1,742 patients with a nonanterior myocardial infarction (relative risk 0.81; 95% confidence interval 0.51 to 1.30). Power analysis revealed that the negativity of the study was not the result of inadequate sample size. Life table analysis showed no difference in cumulative event rate (p = 0.42) according to site of infarction. Cox regression analysis showed that of 10 clinical covariates, only systolic blood pressure was predictive of stroke (p < 0.001). The use of warfarin did not contribute to the model. Finally, the addition of site of infarction (anterior vs. nonanterior) did not contribute significantly to the Cox model.

CONCLUSIONS

Although there is a significant incidence of stroke after acute myocardial infarction, there is no relation between the occurrence of stroke and site of infarction. These data do not support the presumed causal relation between anterior myocardial infarction, thrombus and stroke.

Electrocardiographic changes associated with acute cerebrovascular disease: a clinical review

Patients with acute vascular disorders of the CNS demonstrate an abundance of both rhythm and morphologic changes in their ECG. Of these a few will demonstrate myocardial dysfunction and or damage. The value of the ECG in evaluating and predicting which patients will have myocardial dysfunction or damage is questionable. One would assume the echocardiogram would be of more help than the ECG in identifying patients with myocardial damage; however, little data are available. The reason for the poor correlation between ECG findings and clinical correlates has not been explained to date, but it is possible to postulate a theory. There are two mechanisms that might mediate ECG changes in these patients, ie, autonomic neural stimulation from the hypothalamus or elevated circulating catecholamines. Hypothalamic stimulation may cause ECG changes without associated myocardial damage whereas elevated catecholamines may result in myocardial damage. This might explain why so many patients have ECG changes and very few have demonstrable myocardial damage in general, or ischemic damage in particular. That cardiac antiischemic therapy does not change mortality may relate to the fact that treatment has been directed towards patients with ECG changes, which in turn do not correlate with myocardial damage. Better patient selection for such therapy might rest upon demonstration of wall motion abnormalities on echocardiogram. The weakness of this strategy is that many patients with stroke have preexisting coronary disease and wall motion abnormalities and thus echo findings may only document remote infarction rather than acute ischemia.

Embolic potential, prevention and management of mural thrombus complicating anterior myocardial infarction: a meta-analysis

OBJECTIVES

The management of mural thrombus complicating acute anterior myocardial infarction remains controversial in part because of the small size of studies on this topic. We performed a meta-analysis of published studies to address three questions: 1) What is the embolic risk of mural thrombi after myocardial infarction? 2) What is the impact of systemic anticoagulation in reducing the embolic risk of mural thrombi? 3) What is the impact of systemic anticoagulation, thrombolytic therapy and antiplatelet therapy in preventing mural thrombus formation?

METHODS

Studies were identified by a computerized and manual search and were included if they were published in manuscript form in the English-language literature. Pooling of data was performed by calculating the Mantel-Haenszel odds ratio and an event rate difference by the method of DerSimonian and Laird.

RESULTS

The odds ratio for increased risk of emboli in the presence of echocardiographically demonstrated mural thrombus (11 studies, 856 patients) was 5.45 (95% confidence interval [CI] 3.02 to 9.83), and the event rate difference was 0.09 (95% CI 0.03 to 0.14). The odds ratio of anticoagulation versus no anticoagulation in preventing embolization (seven studies, 270 patients) was 0.14 (95% CI 0.04 to 0.52) with an event rate difference of -0.33 (95% CI -0.50 to -0.16). The odds ratio of anticoagulation versus control in preventing mural thrombus formation (four studies, 307 patients) was 0.32 (95% CI 0.20 to 0.52), and the event rate difference was -0.19 (95% CI -0.09 to -0.28). The odds ratio for thrombolytic therapy in preventing mural thrombus (six studies, 390 patients) was 0.48 (95% CI 0.29 to 0.79) with an event rate difference of -0.16 (95% CI 0.10 to -0.42), whereas for antiplatelet agents (two studies, 112 patients) the odds ratio was 1.43 (95% CI 0.04 to 56.8) with an event rate difference of 0.16 (95% CI -0.20 to 0.52).

CONCLUSIONS

This analysis supports the hypotheses that 1) mural thrombus after myocardial infarction poses a significantly increased risk of embolization, 2) the risk of embolization is reduced by systemic anticoagulation, and 3) anticoagulation can prevent mural thrombus formation. Thrombolytic therapy may prevent mural thrombus formation, but evidence for a similar benefit of antiplatelet therapy is lacking.

The management of heart failure: a matter of definition?

The term heart failure has become a label for more than one clinical entity. For many years heart failure has been used to denote patients with various heart diseases who have begun to suffer from fluid retention, pulmonary venous hypertension, or systemic venous hypertension, either alone or in combination. More recently, the term heart failure has been applied to the combination of effort intolerance and reduced left ventricular contractility due to ischemic heart disease or other myocardial disease. Comparison of the results of epidemiological studies and therapeutic trials is complicated by variation in the composition of the patient populations selected for study. Drug treatment of heart failure remains fairly empirical. Distinction should be made between immediate or prognostic benefits related to the etiological diagnosis, and benefits related specifically to prevention and relief of, for example, fluid retention, rhythm disturbances, or ventricular hypertrophy. The response of individual patients to several forms of drug treatment, including digoxin, ACE inhibitors, and beta-blockade, is unpredictable. Prospective identification of patients liable to respond well to these drugs is not yet possible, but would greatly assist the choice of treatment. At present, trial of therapy is required in each patient to establish benefit and to avoid long-term treatment of nonresponders.

Echocardiography in the evaluation of cardiac sources of emboli: the role of transthoracic echocardiography

Cardioembolism is responsible for a significant number of systemic emboli including approximately 15% of all ischemic strokes. Transthoracic echocardiography has contributed to the understanding of cardioembolism and has been used to detect specific and potential cardiac sources of systemic emboli and risk stratify patients with specific clinical findings for subsequent cardiovascular events. Findings from transthoracic echocardiography indicate that stasis is an important prerequisite for intracardiac thrombosis while reversal of stasis and thrombolysis appear operative in embolism of existing thrombus. Transthoracic echocardiography allows a sensitive and specific noninvasive means to detect left ventricular thrombus, valvular vegetation, and intracardiac tumor, lesions that are directly responsible for cardioembolism. Transthoracic echocardiography can also detect lesions that could potentially contribute to cardioembolism but are not specific causes. Examples of these potential lesions include mitral valve prolapse, patent foramen ovale, and interatrial septal aneurysm. Finally, population-based studies and prospective clinical trials have indicated that the results of transthoracic echocardiography have predictive value for subsequent cardiovascular events and hence provide a means for stratification of patients at risk for cardioembolism. The latter is most notable for the group of patients with nonvalvular atrial fibrillation where left ventricular dysfunction and increased left atrial size are independent predictors for subsequent stroke.

Low incidence of stroke in ambulatory patients with heart failure: a prospective study

The current study was undertaken to determine prospectively the risk of cerebral thromboembolism and the prognostic significance of left ventricular thrombus in ambulatory patients with chronic congestive heart failure. A total of 264 ambulatory patients (mean age 62 years, mean left ventricular ejection fraction 27%) were followed prospectively for 24 +/- 9 months to determine the incidence of nonhemorrhagic stroke, transient ischemic attack, and mortality. Two-dimensional echocardiographic studies, performed for clinical indications other than previous systemic thromboembolism in 109 patients, were analyzed to relate the presence of left ventricular thrombus to subsequent outcome. Nine cerebral thromboembolic events occurred in 264 patients during the two-year mean follow-up period, yielding a rate of 1.7 thromboembolic events per 100 patient-years of follow-up. Known risk factors for stroke (hypertension, diabetes mellitus, and/or atrial fibrillation) were present in all nine patients with cerebral thromboembolic events. The 109 patients with echocardiographic studies had more severe heart failure than patients without echocardiographic studies (functional class 2.6 vs 2.1, p < 0.01), greater risk of a thromboembolic event (2.4 vs 1.4 events/100 patient-years of follow-up, p < 0.01), and higher mortality (21.3 vs 5.5 deaths/100 patient-years, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of atherosclerotic lesions in the aorta by transesophageal echocardiography

Transesophageal echocardiographic studies were prospectively performed in 152 consecutive patients older than age 40 years referred to the echocardiography laboratory to assess the prevalence of atherosclerosis in the thoracic aorta and relate this to a history of systemic embolization. Forty-four patients (29%) had at least 1 atherosclerotic lesion in the thoracic aorta. This was associated with a higher prevalence of coronary artery disease (78% of all patients with coronary artery disease), carotid artery disease (88% of all patients with carotid artery disease) and peripheral vascular disease (all symptomatic patients). Forty-two of all patients (28%) had systemic emboli, 20 (48%) of whom had at least 1 atheromatous lesion in the thoracic aorta. Conversely, only 24 of 110 patients (22%) without previous systemic emboli had atheromatous lesions (p < 0.001). It is concluded that atherosclerotic lesions in the thoracic aorta can readily be identified with transesophageal echocardiography. The detection of atherosclerotic plaques of the aorta represents a marker of diffuse atherosclerotic disease, often associated with carotid, coronary and peripheral vascular disease and with the occurrence of systemic emboli. Transesophageal echocardiography may be used serially to investigate whether dietary or pharmacologic maneuvers, or both, can shrink established atherosclerotic plaques in the thoracic aorta.

Prevention of severe neurologic events in the thrombolytic era

The occurrence of various forms of severe neurologic events has been increasingly reported in acute myocardial infarction patients receiving thrombolytic therapy. Strokes have long been known to complicate acute myocardial infarction. The recent attention on severe neurologic events has focused primarily on probable cerebral bleeds. The various forms of severe neurologic events that clinicians are confronted with have unique features and characteristics that will be delineated. The incidence of these events and patient risk factors for cerebral ischemia and cerebral hemorrhage will be outlined. Guidelines that should be adopted to minimize the chance of a patient's suffering a severe neurologic event while at the same time maximizing the number of patients who receive this lifesaving therapy are summarized.

Ischemic stroke and intracranial hemorrhage following thrombolytic therapy for acute myocardial infarction: a risk-benefit analysis

Stroke is a potentially serious complication of acute myocardial infarction (AMI). In the prethrombolytic era, most strokes were attributed to cerebral embolism. On the basis of available information, the occurrence of stroke in the thrombolytic era appears to be less than in the prethrombolytic era. In the thrombolytic era, the occurrence of various forms of intracranial hemorrhage has increasingly been documented in addition to cerebral embolism, with intriguing features. In general, however, the delineation of specific stroke subtypes has been imprecise and must take into account factors that are unique to this setting. Age is a risk factor for both ischemic and hemorrhagic stroke. Potential risk factors for intracranial hemorrhage include hypertension, dosage of fibrinolytic agents, and prior neurologic disease. Potential causes of intracranial hemorrhage include combined fibrinolytic/adjunctive therapies, various cerebrovascular lesions, and head trauma. Existing data suggest that mortality related to stroke complicating AMI is on the decline as well. More research is needed in order to quantify precisely the occurrence and proportions of stroke subtypes, risk factors, and causes in order to define mechanisms and preventive measures.

Effects of intravenous recombinant tissue-type plasminogen activator therapy on the incidence and associations of left ventricular thrombus in patients with a first acute Q wave anterior myocardial infarction

Consecutive survivors of a first Q wave anterior myocardial infarction were studied to observe the impact of recombinant tissue-type plasminogen activator (rt-PA) therapy on the incidence and associations of left ventricular thrombus. Fifty-four patients received rt-PA within 4 hours after the onset of cardiac pain, followed by heparin infusion. Forty-four patients who did not qualify for rt-PA therapy but who were anticoagulated with heparin served as a control group. Two-dimensional echocardiography was performed in all patients on days 3 and 7 to detect thrombi and analyze wall motion. Ejection fraction was determined by radionuclide angiography in all patients on day 7. Apical thrombi were detected on day 3 in three patients (5.5%) who received rt-PA and in eight control patients (18%) (p less than 0.05). All patients with a thrombus had apical dyskinesis and 8 of 11 (73%) had an aneurysm. Of the 87 patients without thrombosis, apical dyskinesis and aneurysm were present in 42 (48%) and 11 (13%) patients, respectively (p less than 0.01). Ejection fractions and wall motion scores of patients without a thrombus were significantly better when compared with data from those with a thrombus. There were fewer patients with apical dyskinesis (17 of 54) in the group receiving rt-PA therapy compared with the control group (36 of 44) (p less than 0.01). Ejection fractions and wall motion scores were better in patients who received rt-PA compared with control subjects (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of left ventricular thrombi formation after thrombolytic therapy with recombinant tissue plasminogen activator, heparin, and aspirin in patients with acute myocardial infarction

To evaluate the prevalence of left ventricular thrombi after thrombolytic therapy, 144 consecutive patients with acute myocardial infarction (AMI) were prospectively studied with two-dimensional echocardiography 1 and 8 days after admission. Patients were treated 2.1 +/- 0.8 hours after the onset of symptoms. Thrombolytic protocol included 120 mg of recombinant tissue plasminogen activator (rt-PA), 5000 IU of heparin, followed by a continuous infusion of 25,000 IU/24 hours for at least 5 days, and 250 mg of aspirin a day. Seventy-six patients had AMI of the anterior wall; of these, seven (9.2%) developed left ventricular thrombi. The remaining 68 patients had infarctions of the inferior wall; of these, two (2.9%) developed left ventricular thrombi. Since anterior wall infarction not treated with thrombolytic therapy is associated with a 25% to 40% rate of left ventricular thrombi, we conclude that early thrombolytic therapy with rt-PA, heparin, and aspirin reduces the formation of left ventricular thrombus in AMI of the anterior wall. Apical left ventricular thrombi developed more frequently in patients with previous infarctions compared with those without (4 of 17 versus 4 of 127, p = 0.01). During the 12-month follow-up period, no patient in the study had manifestations of peripheral emboli.