Frank L. Mikell

Incidence of left-ventricular thrombosis after acute transmural myocardial infarction. Serial evaluation by two-dimensional echocardiography.

To study the incidence of left-ventricular thrombosis after transmural myocardial infarction, we performed serial two-dimensional echocardiography in 70 consecutive patients. Thirty-five patients had inferior-wall infarction: none had a left-ventricular thrombus. The other 35 had anterior-wall infarction: 12 had left-ventricular thrombi. Thrombi were diagnosed an average of five days after the infarction (range, one to 11 days). All patients with left-ventricular thrombi had severe apical-wall-motion abnormalities (akinesis or dyskinesis). Twenty-six of the 35 patients with anterior infarctions had apical akinesis or dyskinesis on echocardiography; left-ventricular thrombi developed in 12 of these 26 (46 per cent). We conclude that patients with severe apical-wall-motion abnormalities during acute transmural anterior myocardial infarction are at high risk for left-ventricular thrombosis. This high-risk group can be identified before the development of left-ventricular thrombi. Patients with inferior infarction or anterior infarction without a severe apical-wall-motion abnormality are at low risk.

Embolic potential of left ventricular thrombi detected by two-dimensional echocardiography.

We sought to determine whether an association existed between the echocardiographic appearance of left ventricular thrombi and systemic embolization. We reviewed the clinical and echocardiographic characteristics of 60 patients who underwent diagnostic two-dimensional echocardiography for left ventricular thrombi. Sixteen of these 60 patients (27%) had evidence of systemic embolization. Multiple echocardiographic characteristics of left ventricular thrombi were analyzed, including mobility, shape, heterogeneity, echo density, layering, central echo lucency, presence within an aneurysm, and association with low-density swirling echoes. Incidence of embolization was significantly higher in patients with thrombi that were mobile or protruded into the left ventricular cavity (p less than .002 and p less than .05, respectively). Bayesian analysis indicated that the pretest likelihood for embolization was 27% and increased in the presence of mobility, central echo lucency, and protrusion to 60%, 50%, and 40%, respectively. A stepwise regression indicated that mobility was the first and protrusion the second most helpful echocardiographic characteristic in identifying patients with embolic phenomena. Clinical features were of less help in identifying the risk for embolization of patients with left ventricular thrombi. Nine of 31 patients (29%) with recent myocardial infarction (less than 3 weeks) has emboli in contrast to five of 26 patients (19%) with remote myocardial infarction (greater than 3 weeks) (p = NS). The three patients without infarction had congestive cardiomyopathy and two had emboli.

Echocardiography in diagnostic assessment of stroke.

We assessed the use of echocardiography in the evaluation of stroke by recording M-mode and two-dimensional (2D) echocardiograms in 100 consecutive hospitalized patients. Of the 95 persons satisfactorily imaged with 2D echocardiography, 47 lacked clinical and routine laboratory evidence of heart disease; no potential embolic source or other finding that altered therapy was diagnosed by echocardiography. In the remaining 48 patients with clinical or routine laboratory evidence of heart disease, two with left ventricular thrombus as a potential embolic source were identified by 2D echocardiography. M-mode echocardiograms failed to detect the thrombus in either patient. No patients with left atrial thrombi, mitral stenosis, cardiac tumor, or vegetations suggesting endocarditis were identified. One patient had possible mitral valve prolapse. Echocardiograms in patients lacking other available evidence of heart disease are unlikely to yield findings that alter the clinical approach to patients with stroke; echocardiography in stroke patients with clinically evident heart disease may have greater clinical utility; additional study of the role of echocardiography in selected subgroups of stroke patients is indicated.

Functional consequences of interventricular septal involvement in right ventricular infarction: Echocardiographic, clinical, and hemodynamic observations

Although ischemic involvement of the interventricular septum (IVS) may occur in patients with right ventricular infarction (RVI), the potential functional significance of such involvement has not been explored. In 10 patients with hemodynamically evident RVI, ischemic involvement of the IVS was assessed by measuring IVS systolic thickening on M-mode echocardiography. Six patients (group I) had decreased IVS systolic thickening, an echocardiographic indicator of ischemia, or infarction, while four (group II) did not. Group I had significantly higher right ventricular filling pressures (19 +/- 3 vs 12 +/- 5 mm Hg, p = 0.04) and right ventricular end-diastolic echocardiographic dimensions (32 +/- 8 vs 20 +/- 3 mm; p = 0.02) than group II. Paradoxic septal motion was noted only in group I patients (p = 0.01). Left ventricular filling pressures, left ventricular end-diastolic dimensions, and systolic thickening of the left ventricular posterior wall (LVPW) were not significantly different between the groups. Three group I patients died; all had decreased systolic thickening of both the IVS and LVPW. In each, autopsy confirmed infarction of the right ventricular free wall, IVS, and LVPW. In patients with right ventricular infarction, ischemic involvement of the interventricular septum may have important consequences for both right and left ventricular function.

Two-Dimensional Echocardiography Detection of Intracardiac Thrombi

Two-dimensional echocardiography is a useful, if not the preferred, technique currently available for the detection of intracardiac thrombi [1–12]. This is largely due to the ability of two-dimensional echocardiography to image in multiple tomographic sections all chambers of the heart as well as the adjacent proximal connections of the great vessels, to view spatial relationships among normal and abnormal intracardiac structures, and to assess motion characteristics of intracardiac structures in addition to their anatomy. Furthermore, two-dimensional echocardiography is non-invasive, inexpensive, and easily applied with a high rate of successful diagnostic imaging [13] even at the bedside in seriously ill patients [14]. The technique can be applied to the longitudinal study of patients with intracardiac thrombi [15] and already has provided previously unavailable information regarding the natural history and response to therapy of certain intracardiac thrombi [12, 14–16]. Lastly, there are certain features of the two-dimensional ultrasonic technique which may eventually allow acquisition of relatively unique information on intracardiac thrombi. For example, study of the tissue acoustic properties of thrombus [17–19] may ultimately improve diagnostic accuracy and provide clinically useful insights of intracardiac thrombosis.