Gerard Kan

Embolic Potential of Left Ventricular Thrombus After Myocardial Infarction: A Two-Dimensional Echocardiographic Study of 119 Patients

Left ventricular thrombus complicating myocardial infarction was diagnosed by two-dimensional echocardiography in 119 patients. The infarct site was anterior in 98 patients and inferior in 11. Systemic embolism occurred in 26 patients (stroke in 18, lower limb embolism in 7 and mesenteric embolism in 1). A protruding configuration of the thrombus was more common in the patients with embolism than in those without (23 [88%] of 26 versus 17 [18%] of 93) (p less than 0.01). Free mobility of the thrombus was found in 15 (58%) of 26 and 3 (3%) of 93 cases, respectively (p less than 0.01). In predicting embolism, protruding thrombus configuration had a sensitivity of 88% and a specificity of 82%, and positive and negative predictive accuracy was 57 and 96%, respectively. For free mobility of the thrombus, sensitivity was 58%, specificity 97%, positive predictive accuracy 85% and negative predictive accuracy 89%. In the 46 patients whose echocardiogram was obtained during the hospital admission for the index infarct, repeat echocardiograms were obtained during oral anticoagulant therapy. Twelve of these 46 patients had embolism and 2 of the 12 died. In seven of these patients, full dose oral anticoagulant therapy had been given before embolism occurred and in five it was started after an embolic event. The thrombus decreased in size or disappeared in six patients; in four the thrombus showed no change, and in two of these four emboli recurred despite anticoagulation. It is concluded that two-dimensional echocardiography may help delineate the embolic potential of left ventricular thrombus complicating myocardial infarction and may be of value in weighing the benefits and disadvantages of oral anticoagulant therapy.

Detection and quantification of acute, isolated myocardial infarction by two dimensional echocardiography

Ninety consecutive patients with acute, isolated myocardial infarction were evaluated with two dimensional echocardiography. Satisfactory echocardiograms were obtained in 66 patients (73 percent). All patients were studied 2 to 12 hours after the onset of symptoms. Sixty patients had additional studies at 48 and 72 hours. Long axis views were obtained at the base, body and apex of the left ventricle. Five short axis views of the left ventricle were obtained at different levels from the cardiac base to the apex. The individual short axis views, corrected for the end-diastolic internal diameter of the left ventricle, were divided into equal segments and the area of asynergy in each view was estimated. Infarct localization was similar on electrocardiography and echocardiography in 62 of 66 patients. In two dimensional echocardiography in one patient. The results of an echocardiographic study in one patient were false negative. During the study period the individual asynergic area remained stable. The initial asynergic area correlated well (r = 0.87, p less than 0.01) with the peak value of the isoenzyme of creatine kinase (CK-MB), which occurred hours later. Thus, two dimensional echocardiography is a reliable method to localize and quantify, early after the onset of symptoms, the eventual extent of myocardial involvement in patients with acute, isolated infarction.

Two-dimensional echocardiography during percutaneous transluminal coronary angioplasty

In order to study myocardial and clinical events during transient coronary occlusion in humans, two-dimensional echocardiography was continuously performed in 15 patients undergoing 49 balloon inflations during percutaneous transluminal coronary angioplasty (PTCA). Transient segmental asynergy developed in all patients 8 +/- 3 seconds after balloon inflation and returned to baseline 19 +/- 8 seconds after balloon deflation. Segmental dyskinesis was seen in only 8 of 11 patients undergoing PTCA of the left anterior descending artery (LAD). A wall motion score, based on degree of asynergy of 13 segments of the left ventricle, was significantly higher during LAD than during right coronary artery inflation (7.9 +/- 1.3 vs 4.0 +/- 1.4, p less than 0.01). Left ventricular size index increased significantly during balloon inflation, from 179 +/- 9 to 196 +/- 10 mm (p less than 0.01). Four patients developed transient ST segment changes in the extremity leads of the ECG and five patients had angina pectoris. The very first sign of ischemia in three patients, who developed all of these symptoms together, was consistently asynergy, followed by ECG changes, and last, angina pectoris. Thus during PTCA, transient asynergy and left ventricular dilatation develop, which are often clinically silent.

Echocardiographic-cineangiographic correlation in detecting left ventricular aneurysm: A prospective study of 422 patients

Four hundred twenty-two consecutive patients with a documented myocardial infarction underwent cardiac catheterization and echocardiographic examination. Adequate two dimensional echocardiograms were obtained in 386 patients (91 percent). Left ventricular aneurysm was defined echocardiographically and cineangiographically as a well demarcated bulge in the contour of the left ventricular wall during both diastole and systole, demonstrating dyskinesia or akinesia. Cineangiography was considered as the standard for the diagnosis of left ventricular aneurysm. The site of aneurysm was mainly anteroapical. An aneurysm was judged present on cineangiography in 111 patients and on echocardiography in 118 patients. The presence and absence of an aneurysm echocardiographically correlated in 103 and 260 patients, respectively, with cineangiography. In 8 patients a cineangiographically identified aneurysm was not manifested echocardiographically, whereas in 15 patients an aneurysm identified on echocardiography was not evident on cineangiography. Thus two dimensional echocardiography can detect or exclude a left ventricular aneurysm with a high level of sensitivity (93 percent) and specificity (94 percent).

Incidence, timing and prognostic value of left ventricular aneurysm formation after myocardial infarction: A prospective, serial echocardiographic study of 158 patients

Serial 2-dimensional echocardiography was performed prospectively in 158 consecutive patients with first acute myocardial infarction (AMI) to determine the incidence of left ventricular (LV) aneurysm formation and the time course required for, and the clinical significance of, onset of LV aneurysm formation. Studies were performed throughout the first 5 days and after 3 months and 1 year. LV aneurysm was defined as an abnormal bulge in the LV contour during both systole and diastole. Eighty-four patients had anterior, 68 posterior and 6 anteroposterior AMI defined echocardiographically. During the study period, LV aneurysm was found in 35 of 158 patients (22%): in anterior AMI in 27, in posterior AMI in 6 and in anteroposterior AMI in 2. No new aneurysm developed after 3 months. Early aneurysm formation, during the first 5 days after AMI, was seen in 15 patients with anterior infarction. Twelve of these 15 (80%) died within 1 year (10 within 3 months), in contrast to 5 (25%) of the remaining 20 patients with LV aneurysm (p less than 0.05). Dyskinesia of the anterior wall in the acute stage usually resulted in aneurysm formation. Thus, LV aneurysm formation is seen in 22% of mostly anterior AMI and occurs within 3 months after AMI. Early aneurysm formation is associated with a high 3-month (67%) and 1-year (80%) mortality rate.

Comparison of two-dimensional echocardiography with radionuclide angiography during hynamic exercise for the detection of coronary artery disease

Two-dimensional echocardiography (2DE) was performed during 30-degree left lateral decubitus bicycle exercise in 52 patients who underwent cardiac catheterization for suspected coronary artery disease (CAD). Adequate echocardiograms were obtained in 39 patients (75%). Thirty-five of these patients underwent radionuclide angiography (RNA) with the same exercise protocol as for echocardiography. Exercise-induced or increased initial asynergy was considered to be a positive test by both 2DE and RNA. Echocardiographic, scintigraphic, and coronary angiographic data were compared to each other. Significant CAD (greater than 50% luminal obstruction) was present in 26 patients (66%). One of 15 patients with exercise-induced asynergy by 2DE had no CAD. Six 2DE and two RNA studies during exercise were falsely negative, sensitivity 76% versus 91%. Inclusion of RNA ejection fraction data would increase the sensitivity but decrease the specificity of RNA. Exercise-induced septal asynergy was far more frequently present by 2DE than by RNA (11 versus 6) in the 17 patients who had exercise-induced anterior asynergy by both methods. We conclude that it was possible to perform exercise 2DE in 75% of our patients. Exercise-induced asynergy on 2DE was specific (92%) for CAD. The sensitivity of 2DE in detecting CAD was less than that of RNA.

Two-dimensional echocardiographic appearance of left ventricular thrombi with systemic emboli after myocardial infarction☆

To test the hypothesis that left ventricular (LV) thrombi that project into the lumen and are mobile are more likely to embolize than those that do not have these characteristics, the 2-dimensional echocardiograms of 16 patients with LV thrombi after myocardial infarction were retrospectively reviewed. Ten had evidence of peripheral embolization and 6 did not. The studies were reviewed in random order by an observer blinded to the clinical data. Each echocardiogram was graded as showing a protruding or nonprotruding thrombus and the presence or absence of increased mobility. The thrombus projected into the lumen on the echocardiograms of 8 of 10 patients who had had emboli and in 0 of 6 who had not. The thrombus had increased mobility in 4 of 10 patients with emboli and 0 of 6 without. Thus, LV thrombi that project into the lumen and have increased mobility are more likely to embolize than those without these characteristics.

Thallium-201 scanning to decide CCU admission in patients with non-diagnostic electrocardiograms.

To determine the value of thallium-201 scintigraphy as a decisive factor in admission policy for patients with acute chest pain and nondiagnostic electrocardiograms, we undertook a prospective study in 149 such patients. The interval between pain and scan never exceeded 12 hr. Of 57 patients in whom a defect was seen, 34 had an acute infarction, 7 developed infarction within 2 months, and in 11 coronary heart disease was proven by angiography or strongly suggested by stress tests (ECG and thallium-201 scan). In 13 patients with an equivocal scan, coronary heart disease was proven or strongly suggested in 5. Of 79 patients with a normal scan, only 1 had acute infarction, and stress tests were positive in 6 and negative in 72. In these 72 no cardiac event occurred during a 1-year follow-up. Thallium-201 scintigraphy can help to select those patients with acute chest pain and nondiagnostic electrocardiograms who need observation in a CCU.

Assessment of left ventricular aneurysm resectability by two-dimensional echocardiography

Mortality of surgical resection of a left ventricular (LV) aneurysm is largely determined by size and function of nonaneurysmal or residual myocardium. A residual myocardial index was determined using 2-dimensional echocardiography (2-D echo) in 56 consecutive patients scheduled for LV aneurysmectomy, and these results were correlated with surgical outcome. The index was calculated using 3 apical cross sections: the 2- and 4-chamber views and the long-axis view. These views were recorded at mutual angles of 60 degrees. In each view the end-diastolic length of normally moving endocardium of the 2 opposite walls was expressed as a fraction of the end-diastolic LV long axis. The index was assessed by averaging the 6 ratios obtained. In 41 survivors the index ranged from 40 to 71% (mean +/- standard deviation 53 +/- 7.8) and in 15 nonsurvivors from 29 to 67% (mean 38 +/- 8.5, p less than 0.01). With 1 exception, this echocardiographic index sharply separated survivors from nonsurvivors. The lower limit to survive aneurysmectomy was 40%.

Regional and Global Left Ventricular Function Analysis

The severity of left ventricular dysfunction is one of the most important prognostic indicators in the patient with coronary artery disease [1–9]. Initial reports on the assessment of left ventricular ejection fraction from M-mode echocardiograms were promising [10–13], but subsequent studies gave less satisfactory results [14–16], especially in patients with coronary artery disease. The main reason for this is that the two small samples of left ventricular myocardium contained in the unidimensional “ice-pick” view of the M-mode echocardiogram are not representative of the left ventricle as a whole. Multiple-element B-mode scanning [17] and electrocardiogram-triggered composite B-mode scanning [18–20] were the first answers to this problem, soon superseded by real-time two-dimensional echocardiography. The latter can provide an overview of the whole left ventricular contour in any particular cross section. By mentally recombining various sections, it is even possible to get a three-dimensional impression of the ventricle. Regional asynergy—the hallmark of coronary artery disease—can be accurately assessed by two-dimensional echocardiography [21], and was first used to diagnose and locate acute myocardial infarction in humans by Heger et al [22]. Quantification of infarct size from the number of asynergic segments was the next logical step [23–25]. This chapter addresses the assessment of global and regional left ventricular systolic function in coronary artery disease.