Harvey Feigenbaum

Recommendations for quantitation of the left ventricle by two-dimensional echocardiography. American Society of Echocardiography Committee on Standards, Subcommittee on Quantitation of Two-Dimensional Echocardiograms.

We have presented recommendations for the optimum acquisition of quantitative two-dimensional data in the current echocardiographic environment. It is likely that advances in imaging may enhance or supplement these approaches. For example, three-dimensional reconstruction methods may greatly augment the accuracy of volume determination if they become more efficient. The development of three-dimensional methods will depend in turn on vastly improved transthoracic resolution similar to that now obtainable by transesophageal echocardiography. Better resolution will also make the use of more direct methods of measuring myocardial mass practical. For example, if the epicardium were well resolved in the long-axis apical views, the myocardial shell volume could be measured directly by the biplane method of discs rather than extrapolating myocardial thickness from a single short-axis view. At present, it is our opinion that current technology justifies the clinical use of the quantitative two-dimensional methods described in this article. When technically feasible, and if resources permit, we recommend the routine reporting of left ventricular ejection fraction, diastolic volume, mass, and wall motion score.

Echocardiographic detection of coronary artery disease during dobutamine infusion.

BackgroundTwo-dimensional echocardiography performed during dobutamine infusion hasbeen proposed as a potentially useful method for detecting coronary artery disease. However, the safety and diagnostic value of dobutamine stress echocardiography has not been established. Methods and ResultsIn this study, echocardiograms were recorded during step-wise infusion of dobutamine to a maximum dose of 30 gg/kg/min in 103 patients who also underwent quantitative coronary angiography. The echocardiograms were digitally stored and displayed in a format that allowed simultaneous analysis of rest and stress images. Development of a new abnormality in regional function was used as an early end point for the dobutamine infusion. No patient had a symptomatic arrhythmia or complications from stress-induced ischemia. Significant coronary artery disease (<50% diameter stenosis) was present in 35 of 55 patients who had normal echocardiograms at rest. The sensitivity and specificity of dobutamine-induced wall motion abnormalities for coronary artery disease was 89% (31 of 35) and 85% (17 of 20), respectively. The sensitivity was 81% (17 of 21) in those with one-vessel disease and 100% (14 of 14) in those with multivessel or left main disease. Forty-one of 48 patients with abnormal echocardiograms at baseline had localized rest wall motion abnormalities. Fifteen had coronary artery disease confined to regions that had abnormal rest wall motion, and 26 had disease remote from these regions. Thirteen of 15 patients (87%) without remote disease did not develop remote stress-induced abnormalities, and 21 of 26 (81%) who had remote disease developed corresponding abnormalities. ConclusionsEchocardiography combined with dobutamine infusion is a safe and accurate method for detecting coronary artery disease and for predicting the extent of disease in those who have localized rest wall motion abnormalities.

Dobutamine stress echocardiography: correlation with coronary lesion severity as determined by quantitative angiography.

This study was performed 1) to determine the ability of dobutamine stress echocardiography to detect stenoses in individual coronary arteries by utilizing a new model of coronary artery distribution; 2) to evaluate its ability to detect coronary artery stenosis with a minimal lumen diameter less than 1 mm; and 3) to correlate the heart rate at which a positive test result occurs with the severity of coronary artery disease. Eighty-five patients were identified who underwent both dobutamine stress echocardiography and quantitative coronary angiography. During incremental infusion of dobutamine, two-dimensional echocardiograms were obtained at rest, during low and peak stress and after stress. Echocardiograms were interpreted with use of a modified 16-segment model with an anteroinferior overlap scheme. The overall sensitivity of the technique for the detection of significant coronary artery disease (diameter stenosis greater than or equal to 50%) was 95%; specificity was 82% and accuracy 92%. The sensitivity for detection of individual coronary artery lesions did not differ significantly (p greater than 0.05) in the three major coronary artery distributions (79% left anterior descending, 70% left circumflex, 77% right coronary artery). Among 35 stenoses with a minimal lumen diameter less than 1 mm, the test result was positive in 30 (86%). Test results were correctly positive for 88%, 82% and 86% of stenoses in the left anterior descending, left circumflex and right coronary artery distributions, respectively. Multivessel disease was present in 11 of 16 patients with normal wall motion at rest who developed a wall motion abnormality at a heart rate less than 125 beats/min. The incidence of multivessel disease was statistically higher in patients with positive findings on a dobutamine stress echocardiogram at a heart rate less than or equal to 125/min. In conclusion, dobutamine stress echocardiography has high sensitivity and specificity for the detection and localization of coronary artery disease. Detection of stenosis in individual coronary arteries is improved in those lesions with a minimal lumen diameter less than 1 mm. Patients with a positive test result at a heart rate less than or equal to 125 beats/min have a high likelihood of multivessel coronary artery disease.

An echocardiographic index for separation of right ventricular volume and pressure overload

Abnormal motion of the interventricular septum has been described as an echocardiographic feature of both right ventricular volume and pressure overload. To determine if two-dimensional echocardiography can separate these two entities and distinguish them from normal, geometry and motion of the interventricular septum in short-axis views of the left ventricle were evaluated in 12 normal subjects and 35 patients undergoing cardiac catheterization. Thirteen of the 35 patients had uncomplicated atrial septal defect with associated right ventricular volume overload, but no elevation in pulmonary artery pressure. The 22 remaining patients had a pulmonary artery systolic pressure greater than 40 mm Hg and, thus, constituted the group with right ventricular pressure overload. An eccentricity index, defined as the ratio of the length of two perpendicular minor-axis diameters, one of which bisected and was perpendicular to the interventricular septum, was obtained at end-systole and end-diastole. In all normal subjects, the eccentricity index at both end-systole and end-diastole was essentially 1.0, as would be expected if the left ventricular cavity was circular in the short-axis view. In patients with right ventricular volume overload, the eccentricity index was approximately 1.0 at end-systole, but was significantly increased at end-diastole (mean eccentricity index = 1.26 +/- 0.12) (p less than 0.001). In patients with right ventricular pressure overload, the eccentricity index was significantly greater than 1.0 at both end-systole and end-diastole (1.44 +/- 0.16 and 1.26 +/- 0.11, respectively) (p less than 0.001). These results suggest that an index of eccentric left ventricular shape which reflects abnormal motion of the interventricular septum can be defined.(ABSTRACT TRUNCATED AT 250 WORDS)

Symptoms, adverse effects, and complications associated with dobutamine stress echocardiography. Experience in 1118 patients.

BackgroundThe use of dobutamine stress echocardiography for the evaluation of coronary artery disease is rapidly expanding. New applications of the technique are being investigated in a wide variety of patients including those with advanced coronary artery disease. Despite its widespread use, the safety of dobutamine stress echocardiography has not been sufficiently documented. Methods and ResultsA consecutive series of 1118 patients undergoing dobutamine stress echocardiography for evaluation of known or suspected coronary artery disease form the basis of this report. Dobutamine stress testing was performed for evaluation of chest pain, risk assessment before noncardiac surgery, after recent myocardial infarction, or as a part of ongoing research protocols. Over the study period, the maximal dose of dobutamine used was increased from 30 to 50 jug/kg per minute, and atropine was used in 420 (37%) patients. There were no occurrences of death, myocardial infarction, or episodes of sustained ventricular tachycardia as a result of dobutamine stress testing. The major reasons for test termination were achievement of target heart rate in 583 patients (52.1%), maximum dose in 255 (22.8%), and angina pectoris in 142 (13%). The test was terminated in 36 (3%) patients because of noncardiac side effects including nausea, anxiety, headache, tremor, and urgency. Angina pectoris occurred in 216 (19.3%) patients. Sublingual nitroglycerin, a short-acting 0-blocker, or both types of medication were administered in 80 of these patients for relief of angina pectoris. None required intravenous nitroglycerin. A total of 736 (65%) patients had stable sinus rhythm throughout the test. The most common arrhythmias were frequent premature ventricular complexes (six or more per minute) in 172 patients (15%), and frequent premature atrial complexes in 86 (8%). There were 40 patients with nonsustained ventricular tachycardia. None had symptoms associated with the tachycardia, and only one received specific pharmacological treatment to prevent recurrence of the arrhythmia after the test was terminated. The patients who were evaluated after recent myocardial infarction and those who received atropine did not have a higher frequency of ventricular tachycardia compared with those without recent infarction and those not receiving atropine. ConclusionsDobutamine stress echocardiography was safely performed using supplemental atropine and an aggressive dosing protocol. Noncardiac side effects were usually minor. Arrhythmias were well tolerated and rarely required treatment. In this study, serious complications from myocardial ischemia did not occur. Symptomatic ischemia was effectively treated with test termination, sublingual nitroglycerin, or short-acting f-blockers.

Cross-sectional echocardiographic analysis of the extent of left ventricular asynergy in acute myocardial infarction

Cross-sectional echocardiography was used to study left ventricular wall motion in 44 patients with myocardial infarction, and the extent of observed asynergy was correlated with left ventricular function. Echocardiographic studies were performed in short and long axes of the ventricle and nine segments were identified for analysis. Wall motion in each segment was classified as normal, hyperkinetic, hypokinetic, akinetic or dyskinetic. Based on this analysis a wall motion index was derived as an overall assessment of left ventricular asynergy. Left ventricular function was measured by clinical and hemodynamic parameters to note the presence of pulmonary congestion or peripheral hypoperfusion or both.Segmental asynergy was detected in all patients with acute myocardial infarction. Patients with uncomplicated infarction had a wall motion index of 3.2 ± 2.4, which was significantly less than that in patients with pulmonary congestion (9.7 ± 3.1, p < 0.001) or with both pulmonary congestion and hypoperfusion (10.6 ± 4.8, p < 0.001).In nine patients with acute ventricular septal defect or acute mitral regurgitation, wall motion index was 6.7 ± 1.9, significantly less than with other complicated infarcts (p < 0.001) but greater than with uncomplicated infarcts (p < 0.005). Wall motion index also discriminated complicated from uncomplicated infarction when death was used as the end point.Cross-sectional echocardiography provides a method of measuring the extent of left ventricular asynergy during acute myocardial infarction that correlates well with hemodynamic parameters of left ventricular function.

Incomplete mitral leaflet closure in patients with papillary muscle dysfunction.

Clinical acceptance of an association between papillary muscle dysfunction and mitral regurgitation is widespread, despite the lack of objective support. To evaluate a possible association, we performed echocardiographic examinations on 22 patients with prior myocardial infarction and clinical evidence of papillary muscle dysfunction, 40 patients with prior myocardial infarction and no clinical evidence of papillary muscle dysfunction, and 20 normal subjects. There was a unique pattern of incomplete mitral leaflet closure ina high percentage (91%) of infarct patients with mitral regurgitation. In these patients, one or both leaflets we3e effectively arrested within the cavity of the left ventricle during ventricular systole. Dyskinetic wall motion in the region immediately surrounding one of the papillary muscles was present in 23 of 24 patients (96%) with demonstrated incomplete closure. This study provides the first objective evidence that de novo mitral regurgitation in patients with prior myocardial infarction is due to dyskinesis involving the left ventricular myocardium beneath one of the papillary muscles, producing increased tension on the mitral leaflets and preventing normal closure.

Exercise echocardiography: a clinically practical addition in the evaluation of coronary artery disease.

There has been only modest clinical interest in exercise echocardiography because of the technical limitations of the procedure. Recognizing that there have been recent technical advances in the echocardiographic instruments and that echocardiography should, in theory, be an ideal technique for evaluating exercise-induced wall motion abnormalities, a clinically practical method of performing exercise echocardiograms was developed. By obtaining the echocardiograms immediately after treadmill exercise, with the patient sitting at the treadmill, a high percent of studies adequate for interpretation was obtained (92%). The addition of echocardiography to the treadmill exercise test significantly enhanced the diagnostic yield. In addition, in cases of one and three vessel disease, exercise echocardiography identified stenosis in specific coronary arteries. In patients with two vessel disease and left circumflex obstruction, specific vessel identification was less reliable. A high percent of patients with multivessel disease developed wall motion abnormalities with exercise that persisted for at least 30 minutes. It is concluded that echocardiography performed immediately after exercise with the new generation of echocardiographs can be a practical and useful clinical tool.

Cross-sectional echocardiography in acute myocardial infarction: detection and localization of regional left ventricular asynergy.

Left ventricular asynergy associated with acute myocardial infarction was evaluated by crosssectional echocardiography. Patients with acute infarction were studied within 48 hours of admission, and a segmental analysis of left ventricular wall motion was performed using nine segments obtained by short- and long-axis recordings of the left ventricle. By this segmental approach, analysis of wall motion in the entire left ventricle was possible. Complete studies were recorded in 37 of 44 original patients. Segmental wall motion abnormalities were recorded and localized in each of the 37 study patients. Asynergy was detected in 142 segments, and 29 patients had multiple segment involvement. Asynergy was most common in the apical segments of the left ventricle, but the cross-sectional scans permitted detection of asynergy in all segments. Correlation between the ECG and the cross-sectional echocardiogram revealed that 19 of 20 patients with inferior infarction had asynergy in posterior segments, 14 of 14 patients with anterior infarction had asynergy in anterior segments, and three of three patients with anteroinferior infarction had asynergy both anterior and posterior segments. In addition, the location of segmental asynergy followed specific patterns for each ECG subgroup of infarction. In four patients with postmortem examination, 21 of 22 segments that had asynergy by cross-sectional echocardiography also had pathologic evidence of infarction. Therefore, the cross-sectional echocardiogram provides a reliable method for detecting the presence and location of regional asynergy associated with acute myocardial infarction.

Assessment of myocardial perfusion abnormalities with contrast-enhanced two-dimensional echocardiography

A new echocardiographic contrast agent, gelatin-encapsulated microbubbles, that an intramyocardial contrast effect, was evaluated as a marker for the detection of regions of abnormal myocardial perfusion in nine open-chest dogs. The gelatin-encapsulated microbubbles were injected into the aortic root under control conditions and during circumflex coronary artery occlusion. Myocardial perfusion was simultaneously assessed with radioactive microspheres. Echocardiographic contrast enhancement (ECE) was measured in footlamberts (Ft-L) from the videoscreen of an off-line playback system, using a commercially available light meter. A single short-axis section of the left ventricle was divided into octants to analyze myocardial perfusion. The equivalent regions of the echocardiographic image were analyzed for contrast enhancement and wall motion. An ECE > 0.3 Ft-L was seen in all 120 octants analyzed before circumflex coronary artery occlusion and in 48 of 51 (94%) octants with > 50% of normal zone flow during circumflex artery occlusion. An ECE ≤ 0.3 Ft-L identified 19 of 21 octants (with ≤ 50% normal zone flow and all 13 octants with ≤ 25% normal zone flow during coronary artery occlusion. In contrast, wall motion abnormalities (akinesis or dyskinesis) were seen in 13 of 51 octants (25%) with > 50% normal zone flow, and normal wall motion was seen in two of 21 octants (10%) with blood flow ≤ 50% of normal zone flow during circumflex coronary artery occlusion. We could not demonstrate a linear correlation between ECE and the absolute level of myocardial blood flow. We feel this was due to the limitations imposed by imaging an open-chest animal preparation, variation in the number of gelatin-encapsulated microbubbles used for each injection and variations in the echocardiographic gain settings among experiments. We conclude that contrast-enhanced two-dimensional echocardiography with gelatin-encapsulated microbubbles can accurately identify ischemic regions of the left ventricular myocardium. This technique is more accurate than wall motion analysis for detecting myocardial ischemia.