Pathophysiology and Natural History Left Ventricular Aneurysm

A retrospective study was performed to elucidate the process of left ventricular aneurysm formation and its influence on left ventricular enlargement based on serial two-dimensional echocardiographic observations from 150 consecutive patients with first acute anterior myocardial infarction. Echocardiograms were available and interpretable through the entire period of observation in 68 patients. Because of early death in 13 patients, echocardiograms of 55 patients, 22 with and 33 without aneurysm, were analyzed from 1 to 28 days after infarction. Patients with aneurysms were separated into two groups with large (group 1, 11 patients) and small aneurysms (group 2, 1 1 patients) on the basis of ratios of aneurysm to overall left ventricular circumferential length [Lcf-LV(RAO)l and area [Area-LV(RAO)], i.e., Lcf(An/LV)-RAO and Area(An/LV)-RAO, respectively, in the right anterior oblique equivalent view at the time of aneurysm formation, with reference to Forrester's subset. Group 1 consisted of patients with Lcf(An/LV)-RAO of 0.4 or greater or Area(An/LV)RAO of 0.3 or greater while group 2 included patients with Lcf(An/LV)-RAO less than 0.4 or Area(An/LV)RAO less than 0.3. In the test for time trend in these groups with a one-way analysis of variance, LcfLV in RAO equivalent and apical four-chamber views and Area-LV in apical four-chamber view effectively separated group 1 from groups 2 and 3 (without aneurysm) with significance (p < .005, p < .01, and p < .01). In group 1 the incidence of heart failure was significantly higher than that in groups 2 and 3 (77.8% vs 0% and 21. 1%; p < .001, p < .001), and the mortality was high compared with that of the other two groups (38.7% vs 8.3% and 13.2%) showing statistical significance only with group 3 (p < .05). The present criteria for separating patients with left ventricular aneurysm seem useful in predicting future left ventricular enlargement and developing clinical prognosis even at the time of aneurysm formation. Circulation 72, No. 2, 280-286, 1985. LEFT VENTRICULAR aneurysm is a frequent complication associated with acute myocardial infarction and is often the cause of heart failure, intractable arrhythmias, and mural thrombus of the left ventricle. 2 Early diagnosis of this aneurysm is important for the management of the disease, including preload and afterload reduction and surgical intervention.' Although there are several reports on two-dimensional echocarFrom the Division of Cardiology, The First Department of Medicine, Osaka University Medical School, and Divisions of Cardiology, Sakurabashi Watanabe Hospital, Osaka National Hospital, and Ohtemae General Hospital, Osaka, and Department of Gerontology, Kanazawa Medical University, Kanazawa, Japan. Address for correspondence: Masayuki Matsumoto, M.D., Department of Gerontology, Kanazawa Medical University, I-l, Daigaku, Uchinada-cho, Kahoku-gun, Ishikawa Prefecture, 920-02, Japan. Received Jan. 25, 1984; revision accepted April 11, 1985. 280 diographic detection of left ventricular aneurysms,4--6 only Eaton et al.] provided data on the process of left ventricular aneurysm formation. They studied 28 patients with acute transmural myocardial infarction during the first 2 weeks after infarction by serial twodimensional echocardiography, but quantitative analysis was not performed with regard to the degree of expansion of infarct. A clinical review of over 150 patients with first acute anterior myocardial infarction indicated the necessity of a tight retrospective and chronologic analysis of the left ventricular size of these patients with regard to the presence and especially to the size of the left ventricular aneurysm. The consensus was that large left ventricular aneurysms affected successive dilatation of the left ventricle in these paCIRCULATION by gest on A ril 2, 2017 http://ciajournals.org/ D ow nladed from PATHOPHYSIOLOGY AND NATURAL HISTORY-LEFT VENTRICULAR ANEURYSM tients. Therefore two-dimensional echocardiographic observations of the left ventricle were performed in patients with first acute anterior myocardial infarction from days 1 to 28 after infarction. Based on these observations, the study continued toward quantitative estimation of the size of the left ventricular aneurysm and its influence on left ventricular enlargement and clinical prognosis. Materials and methods Patients. Two-dimensional echocardiographic examinations during the period from January 1, 1980, to January 1, 1983, were reviewed in 150 consecutive patients with first acute transmural myocardial infarction, who were admitted within 24 hr of the onset of symptoms. Interpretable two-dimensional echocardiographic recordings were obtained through the entire period of observation in 68 patients. Thirteen of these 68 died within 28 days of infarction; thus serial two-dimensional echocardiography covering all five stages of examination was performed in 55 patients. Forty-eight of these 55 patients and 105 of the total 150 patients underwent left ventriculography in the right anterior oblique (RAO, 30 degrees) and left anterior oblique (LAO, 60 degrees) projections approximately 40 days after infarction. Two-dimensional echocardiography. Serial two-dimensional echocardiograms were recorded on days 1, 3, 7, 14, and 28 after infarction. On each day two-dimensional echocardiograms in the RAO equivalent view (in 55 cases), the short-axis view at the papillary muscle level (in 51 cases), and the apical four-chamber view (in 33 cases) were recorded on 8 mm movie film with a Hitachi 10-A, 72 degree phased-array echocardiograph. The smaller number in studies in the apical-four chamber view was due to the late inclusion of this view in the examination. In this study an echocardiographic aneurysm was defined as an outward bulging of the left ventricular wall with hinge points occurring during both systole and diastole (BCD in the left panel of figure 1).4 5The presence of left ventricular aneurysm and its extent were examined on each day of examination. Quantitative measurement of sizes of the left ventricle and left ventricular aneurysm. For a quantitative assessment of sizes of the overall left ventricle and left ventricular aneurysm, six indexes as shown in the left panel of figure 1 were obtained by tracing the endocardial contour of the RAO equivalent view of the left ventricle in end-diastole. Left ventricular circumferential length [Lcf-LV(RAO)] was measured around the left ventricle from the aortic root to the posterior mitral valve ring (ABCDE in the left panel of figure 1) with a curvemeter. In patients with aneurysms the circumferential length of the aneurysm [Lcf-An(RAO)] was measured around the aneurysm between two hinge points in end-diastole (BCD in the left panel of figure 1) and the ratio of Lcf-An(RAO) to Lcf-LV(RAO) [Lcf(An/LV)-RAO] was calculated. RAO equivalent view (RAO) Apical four chamber view (Ap-4C) Short axis view (SA)