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Biomedical subjects

S G Sawada

Publications and source records attributed to S G Sawada.

At least 19 recordsLinked to original sources
PubMed2001

Detection of subclinical coronary atherosclerosis using two-dimensional, high-resolution transthoracic echocardiography.

OBJECTIVES: We evaluated whether two-dimensional high-resolution transthoracic echocardiography (HR-2DTTE) can detect changes in arterial wall thickness and size associated with subclinical coronary artery disease (CAD). BACKGROUND: Arterial wall thickening, compensatory arterial enlargement and a preserved arterial lumen characterize subclinical atherosclerosis. Detection of these changes during the asymptomatic stage of CAD may allow early treatment and prevention of acute coronary events. METHODS: Twenty-six patients with angiographically proven CAD and 29 normal volunteers underwent HR-2DTTE evaluation of the left anterior descending coronary artery (LAD) using an ATL 5000 echograph (Advanced Technology Laboratories, Bothell, Washington) with a 4 to 7 MHz transducer. Significant (>70%) LAD stenosis was present in 15 patients (mean 82%); 11 patients did not have significant LAD stenosis (mean 26%) and represented a surrogate for subclinical LAD disease. Wall thickness, maximal luminal diameter and external diameter of the LAD were measured. RESULTS: Left anterior descending coronary artery wall thickness was larger in patients (1.9 +/- 0.4 mm) than it was in volunteers (0.9 +/- 0.1 mm, p < 0.001). The external diameter of the LAD was (6.0 +/- 1.1 mm) in patients and (3.9 +/- 0.7 mm) in volunteers (p < 0.001). Luminal diameter was 2.2 +/- 0.5 mm in patients and 2.1 +/- 0.6 mm in volunteers (p = NS). There was no difference in wall thickness (1.9 +/- 0.4 mm vs. 2.0 +/- 0.4 mm), luminal diameter (2.2 +/- 0.5 mm vs. 2.2 +/- 0.4 mm) and external diameter (5.9 +/- 1.0 mm vs. 6.2 +/- 1.2 mm) between the patients with <70% and >70% LAD stenosis. CONCLUSIONS: Left anterior descending coronary artery wall thickness and external diameter are significantly increased in patients with CAD as compared with normal subjects, and HR-2DTTE is sensitive enough to detect these differences. Wall thickness and external diameter are increased to the same extent in patients with obstructive and subclinical LAD disease.

Adult↗
PubMed2001

Arbutamine stimulation detects viable myocardium 4 weeks after coronary occlusion.

At low doses, dobutamine has potent inotropic, but limited chronotropic, effects-properties that may be necessary for detection of hibernating myocardium. The efficacy of other catecholamines, which have more closely coupled inotropic and chronotropic effects, for the detection of viable myocardium is unknown. This study evaluated the efficacy of arbutamine, a catecholamine with potent chrono-tropic effects, for the detection of viable myocardium in a canine model of hibernating myocardium. Contractile reserve was assessed during stepwise arbutamine infusion (dosages of 2.5, 5, 10, 50, and 100 ng/kg/min) at 3 days (early) and 4 weeks (late) after coronary ligation. Segment shortening, wall thickening, and segmental wall motion were assessed by sonomicrometry and echocardiography. After 4 weeks of occlusion, functional recovery was assessed after revascularization. During the early arbutamine study, the sensitivity for predicting functional recovery was highest at a dosage of 50 ng/kg/min, which also produced tachycardia. The sensitivity was 50% for segment shortening, 20% for wall thickening, and 75% for wall motion score. The late arbutamine study had improved sensitivity. The sensitivity was 100% for segment shortening, 80% for wall thickening, and 90% for wall motion score at a dosage of 50 ng/kg/min. At the late arbutamine study, myocardial perfusion reserve in the ischemic zone of dogs with functional recovery was only mildly reduced (2.0 versus 2.6 in nonischemic zones, P =.53). After coronary occlusion, viable myocardium can be detected with high doses of arbutamine that produce tachycardia. However, the sensitivity of arbutamine stimulation for predicting functional recovery is low early after occlusion, but it is improved by 4 weeks after occlusion with adequate perfusion reserve.

Animals↗
PubMed2001

Echocardiographic imaging of technically difficult patients in the intensive care unit: use of optison in combination with fundamental and harmonic imaging.

Previous studies of intravenous contrast agents have excluded patients in the intensive care unit. These patients remain among the most technically difficult to image with ultrasound. We studied the effect of different imaging modalities with and without intravenous contrast (Optison) on endocardial border visualization during echocardiography. Fifty patients in the intensive care unit (32 men, 24 on mechanical ventilator, 10 with chest bandages; mean age, 59 years; mean weight, 91.7 kg; mean height, 67.6 inches) were considered to have technically difficult images when the endocardium could not be visualized in at least 2 of the 6 segments in either apical view. Each patient was studied with the use of fundamental (F), harmonic (H), fundamental + Optison (F + O), and H + O techniques, with standard long-axis, short-axis, and apical 4- and 2-chamber views. Intravenous Optison (0.5 to 1.5 mL) was given before F + O and H + O imaging. There were no contrast-related side effects noted. All images were stored digitally in a quad-screen format. For each set of images, segments (n = 22) were given an endocardial border visualization score of 0 if not visualized, 1 if visualized in either systole or diastole, and 2 if visualized in both. There was stepwise improvement in endocardial border visualization, with mean endocardial border visualization score of 1.09 +/- 0.83 (F), 1.33 +/- 0.81 (H), 1.64 +/- 0.62 (F + O), and 1.90 +/- 0.35 (H + O). There was a statistically significant difference between each group (P <.001). The incremental benefit of Optison was greater with harmonic imaging than with fundamental (P <.001). The use of Optison is safe and effective in the intensive care unit. In combination with harmonic imaging, contrast provides maximal endocardial border delineation during echocardiographic imaging of technically difficult patients in the intensive care unit.

Albumins↗
PubMed1999

Cardiac sympathetic denervation after transmyocardial laser revascularization.

BACKGROUND: Transmyocardial laser revascularization (TMR) has been shown to improve refractory angina not amenable to conventional coronary interventions. However, the mechanism of action remains controversial, because improved myocardial perfusion has not been consistently demonstrated. We hypothesized that TMR relieves angina by causing myocardial sympathetic denervation. METHODS AND RESULTS: PET imaging of resting and stress myocardial perfusion with [13N]ammonia (NH3) and of sympathetic innervation with [11C]hydroxyephedrine (HED) was performed before and after TMR in 8 patients with class IV angina ineligible for CABG or PTCA. A mean of 50+/-11 channels were created in the left ventricle (LV) with a holmium:YAG laser. A semiautomated program was used to determine NH3 uptake and HED retention in the LV. Perfusion and innervation defects were defined as the percentage of LV with tracer uptake or retention >2 SD below normal mean values. All patients experienced improvement in their angina by 2.4+/-0.5 angina classes after surgery, P=0.008. Sympathetic innervation defects exceeded resting perfusion defects in all patients before TMR (34.6+/-27.3% for HED versus 9.4+/-10.8% for NH3, P=0.008). TMR did not significantly affect resting or stress myocardial perfusion but increased the extent of sympathetic denervation in 6 of 8 patients by 27.5+/-15.9%, P=0.03. In the remaining 2 patients, both sympathetic denervation and stress perfusion defects decreased after surgery. CONCLUSIONS: TMR causes decreased myocardial HED uptake in most patients without significant change in resting or stress myocardial perfusion, suggesting that the improvement in angina may be at least in part due to sympathetic denervation.

Aged↗
PubMed1999

Enhanced endocardial visualization with noncontrast harmonic imaging during stress echocardiography.

The diagnostic value of echocardiography hinges on the reader's ability to adequately visualize the endocardium of the left ventricle. This study was designed to evaluate the potential benefit of noncontrast harmonic imaging to enhance endocardial visualization. Eighty consecutive outpatients who underwent treadmill stress echocardiography were randomly assigned to either fundamental or harmonic imaging. The echoes were interpreted by 2 experienced readers. Compared with fundamental imaging, harmonic imaging of tissue improved the overall endocardial visualization score by 35% and 21% for readers 1 and 2, respectively (P <.001). Harmonic imaging also reduced the percentage of nondiagnostic segments by one half (P <.01). In patients undergoing treadmill stress echo, harmonic imaging offers a clinically significant improvement in endocardial visualization.

Echocardiography↗
PubMed1999

A comparison of the interpretation of digitized and videotape recorded echocardiograms.

Conventional echocardiograms are typically recorded on videotape and later reviewed and interpreted by a physician. Although videotape recording is an excellent medium for this purpose, it does have several disadvantages, which may be overcome by digital storage. This study compared the diagnostic accuracy of digitized and videotape recorded echocardiograms. Echocardiographic examinations (n = 110) were recorded simulta-neously on videotape and were digitized with a commercially available frame grabber system. Images were transmitted by an Ethernet link to the network-based computer system and compressed with a nondestructive compression algorithm. Images were reviewed on a personal computer. Images were interpreted by 3 observers, and differences in interpretation were documented. There were 274 findings in 110 patients. Exact agreement in interpretation was found in 83%. A major discrepancy occurred in 2%, and a minor discrepancy occurred in 15%. Most discrepancies occurred in the setting of valvular heart disease. When compared with a consensus interpretation, no significant difference was seen in the number of errors between the digital and videotape interpretation. We conclude that the interpretation of a properly recorded digitized echocardiographic examination yields interpretations equivalent to those of videotape recordings.

Echocardiography↗
PubMed1998

Location of stents in the left anterior descending coronary artery using three dimensionally acquired, two dimensionally displayed transthoracic echocardiography.

The location of left anterior descending arterial stents was documented in 10 of 13 patients using 3-dimensionally acquired, 2-dimensionally displayed transthoracic echocardiography. The echocardiographic appearance of stents was characterized, and the location of the proximal and mid-left anterior descending artery was objectively documented.

Adult↗
PubMed1998

Clinical utility of troponin T levels and echocardiography in the emergency department.

We investigated the clinical utility of cardiac troponin T (TnT) and echocardiography in the emergency department to predict subsequent in-hospital diagnosis and adverse cardiac events. TnT is a cardiac-specific protein released during cell injury such as that following acute myocardial inFarction (MI). Unlike creatine kinase-MB isoenzymes, TnT is increased in a subset of patients with unstable angina, and these may be at higher risk for subsequent cardiac events. Echocardiography is a useful noninvasive imaging technique for the assessment of ischemic heart disease in acute care settings because of its mobility and rapid results. Serial TnT determinations and echocardiographic images were prospectively evaluated in 100 patients with chest discomfort and admitted to the hospital. Serum was obtained for CKMB and TnT on presentation to the emergency department and 4, 8, 16 and 24 hours later. TnT was considered increased when at values greater than 0.1 microg/L. Echocardiograms were recorded on videotape in the emergency department and images reviewed in a blinded fashion for wall-motion abnormalities. When available, current echocardiographic results were compared with previous results to determine whether a new wall-motion abnormality was present. Of the 100 patients (57 men, 43 women), TnT was increased in 21 of 21 with acute MI and 15 of 41 with unstable angina. One of the 38 patients with stable angina had an increased TnT value and died 5 months later of a noncardiac cause. Ninety percent of patients who sustained acute MI had a TnT increase detected within 4 hours of presentation. Fifteen of 18 patients with acute MI and 9 of 37 patients with unstable angina had a new wall-motion abnormality on echocardiography. The combination of TnT levels with echocardiography yielded a positive predictive value of 84% and a negative predictive value of 90% for adverse cardiac events in the follow-up population, which was more accurate than either test analyzed separately. TnT and echocardiography are useful tests in emergency department triage of unstable coronary syndromes. Both tests are predictive of discharge diagnosis and follow-up events. However, the combined utility of TnT levels and echocardiographic imaging is a more powerful predictor of adverse cardiac events than isolated results.

Angina, Unstable↗
PubMed1996

Evaluation using dobutamine stress echocardiography in patients with insulin-dependent diabetes mellitus before kidney and/or pancreas transplantation.

The purpose of this study was to examine the ability of dobutamine stress echocardiography to stratify patients with juvenile onset, insulin-dependent diabetes mellitus who are being considered for kidney and/or pancreas transplantation, into high-or low-risk groups for future cardiac events. Fifty-three such patients underwent dobutamine stress echocardiography before kidney and/or pancreas transplantation. Cardiac events, including cardiac death, nonfatal myocardial infarction, unstable angina, pulmonary edema, and need for coronary revascularization, occurring between the time of the dobutamine stress echocardiogram and the last patient follow-up contact were retrospectively identified. Twenty patients 938%) had an abnormal dobutamine stress echocardiogram. Eleven patients had 15 cardiac events over a mean (+/- SD) follow-up period of 418 +/- 269 days. Event rates were 45% among those with an abnormal, versus 6% among those with a normal dobutamine stress echocardiogram (p = 0.002). The result of the dobutamine stress test independently predicted prognosis in a multivariate analysis (p = 0.003, odds ratio = 12.7). We conclude that dobutamine stress echocardiography accurately stratifies patients with juvenile onset, insulin-dependent diabetes being considered for kidney and/or pancreas transplantation for risk of future cardiac events.

Adult↗
PubMed1995

Assessment of hibernating myocardium by dobutamine stimulation in a canine model.

OBJECTIVES: The purpose of this study was to 1) develop an animal model of hibernating myocardium, and 2) evaluate the ability of dobutamine stimulation to detect hibernating myocardium using both qualitative and quantitative assessment of regional myocardial function. BACKGROUND: Left ventricular dysfunction may be due to chronic ischemia with or without myocardial infarction and may improve after coronary blood flow is enhanced by revascularization procedures. This condition has been coined "hibernating myocardium" and variably defined in recent years. The results of recent clinical studies suggest that dobutamine echocardiography may be useful for detecting viable myocardium in patients with left ventricular dysfunction. METHODS: Twenty-one dogs underwent initial operation. Sonomicrometer crystals were implanted, and baseline measurements of segment shortening and wall thickening (by echocardiography) were made. A coronary artery was ligated; the chest was closed; and measurements were repeated. Dobutamine was incrementally infused with determination of wall thickening and segment shortening at baseline and on days 3 and 7 and weeks 2 and 4 after coronary artery occlusion. Finally, the chest was reopened; the ligated vessel was bypassed; and measurements were repeated. RESULTS: Of the 10 dogs that completed the entire protocol, 7 had varying degrees of nontransmural myocardial infarction (group 1), and 3 had complete transmural myocardial infarction (group 2). In group 1, baseline function was significantly impaired compared with preligation function but increased during dobutamine infusion. When reperfused after 4 weeks, both wall thickening and segment shortening increased significantly. In group 2, significant changes were not seen during the dobutamine studies or after reperfusion. Myocardial perfusion during dobutamine infusion increased in group 1 but did not change in group 2. CONCLUSIONS: We demonstrated improvement in chronically dysfunctional myocardium after restoration of previously interrupted myocardial blood flow in dogs after nontransmural myocardial infarction, thus validating a canine model of hibernating myocardium. As assessed by two independent methods, dobutamine infusion identified hibernating myocardium in an animal model.

Animals↗
PubMed1994

Positron emission tomography detects evidence of viability in rest technetium-99m sestamibi defects.

OBJECTIVES: The purpose of this study was to determine the relative value of single-photon emission computed tomographic (SPECT) imaging at rest using technetium-99m methoxyisobutyl isonitrile (technetium-99m sestamibi) with positron emission tomography for detection of viable myocardium. BACKGROUND: Recent studies comparing positron emission tomography and thallium-201 reinjection with rest technetium-99m sestamibi imaging have suggested that the latter technique underestimates myocardial viability. METHODS: Twenty patients with a previous myocardial infarction underwent rest technetium-99m sestamibi imaging and positron emission tomography using fluorine (F)-18 deoxyglucose and nitrogen (N)-13 ammonia. In each patient, circumferential profile analysis was used to determine technetium-99m sestamibi, F-18 deoxyglucose and N-13 ammonia activity (expressed as percent of peak activity) in nine cardiac segments and in the perfusion defect defined by the area having technetium-99m sestamibi activity < 60%. Technetium-99m sestamibi defects were graded as moderate (50% to 59% of peak activity) and severe (< 50% of peak activity). Estimates of perfusion defect size were compared between technetium-99m sestamibi and N-13 ammonia. RESULTS: Sixteen (53%) of 30 segments with moderate defects and 16 (47%) of 34 segments with severe defects had > or = 60% F-18 deoxyglucose activity considered indicative of viability. Fluorine-18 deoxyglucose evidence of viability was still present in 50% of segments with technetium-99m sestamibi activity < 40%. There was no significant difference in the mean (+/- SD) technetium-99m sestamibi activity in segments with viable (40 +/- 7%) and nonviable segments (49 +/- 7%, p = 0.84). Of the 18 patients who had adequate F-18 deoxyglucose studies, the area of the technetium-99m sestamibi defect was viable in 5 (28%). In 16 patients (80%), perfusion defect size determined by technetium-99m sestamibi exceeded that measured by N-13 ammonia. The difference in defect size between technetium-99m sestamibi and N-13 ammonia was significantly greater in patients with viable (21 +/- 9%) versus nonviable segments (7 +/- 9%, p = 0.007). CONCLUSIONS: Moderate and severe rest technetium-99m sestamibi defects frequently have metabolic evidence of viability. Technetium-99m sestamibi SPECT yields larger perfusion defects than does N-13 ammonia positron emission tomography when the same threshold values are used.

Adult↗
PubMed1994

Dobutamine stress echocardiography: detection of coronary artery disease in patients with dilated cardiomyopathy.

OBJECTIVES: This study attempted to determine the safety and accuracy of dobutamine stress echocardiography for detection of coronary artery disease in patients with dilated cardiomyopathy. BACKGROUND: Detection of regional wall motion abnormalities at rest does not reliably distinguish ischemic from nonischemic cardiomyopathy. Previous studies have shown that dobutamine stress echocardiography safely and accurately identifies coronary artery disease in patients without dilated cardiomyopathy. METHODS: Seventy patients with dilated cardiomyopathy underwent dobutamine stress echocardiography. Echocardiograms were obtained at baseline and at low (5 to 10 micrograms/kg body weight per min) and peak doses of dobutamine. Rest and stress left ventricular wall motion scores were derived from analysis of regional wall motion. Fifty-four subjects underwent coronary angiography. RESULTS: Dobutamine infusion was terminated after achievement of the target heart rate or maximal protocol dose in 49 patients (70%), ischemia in 12 (17%), arrhythmia in 4 (6%) and side effects in 5 (7%). No patient had prolonged ischemia or sustained arrhythmia. Of those with angiographic studies, 40 had significant coronary artery disease (> or = 50% diameter stenosis). Use of the change in global wall motion score index from low to peak dose resulted in a sensitivity of 83% for dobutamine stress echocardiography and a specificity of 71% for detection of coronary artery disease. Sensitivity for detection of triple-, double- and single-vessel disease was 100%, 83% and 69%, respectively. CONCLUSIONS: Dobutamine stress echocardiography safely provides diagnostic information in patients with dilated cardiomyopathy. This technique has high sensitivity for multivessel coronary artery disease but only moderate specificity.

Adult↗
PubMed1993

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

BACKGROUND: The 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 RESULTS: A 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 micrograms/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 beta-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. CONCLUSIONS: Dobutamine 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 beta-blockers.

Angina Pectoris↗
PubMed1992

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.

Adult↗
PubMed1992

Distinguishing ischemic cardiomyopathy from nonischemic dilated cardiomyopathy with coronary echocardiography.

Transthoracic echocardiographic examination of the proximal left coronary system was performed in 59 patients who had dilated cardiomyopathy to determine if this technique could distinguish between ischemic and nonischemic dilated cardiomyopathy. With use of annular array transducers (3.5 or 5 MHz) and digital image processing, echocardiographic visualization of the coronary arteries was successful in 55 (93%) of 59 patients. As assessed by coronary angiography, 32 subjects had ischemic cardiomyopathy and 27 had nonischemic cardiomyopathy. Twenty-seven (84%) of the 32 patients who had coronary artery disease and 24 (89%) of the 27 patients with nonischemic cardiomyopathy were correctly identified. The accuracy of coronary echocardiography was 86% in the entire study group and 93% when patients with inadequate studies were excluded. All subjects who had ischemic cardiomyopathy had evidence of disease by coronary echocardiography or segmental wall motion abnormalities. Multivariate analysis permitted correct classification of 93% of all subjects based on the results of the coronary echocardiogram, evaluation of segmental wall motion and a history of prior myocardial infarction. The correct diagnosis was made in 86% when the results of coronary echocardiography were excluded from analysis using all other echocardiographic and clinical variables. Transthoracic coronary echocardiography can be performed with a high degree of success in patients with dilated ventricles and the technique can reliably distinguish between ischemic and nonischemic dilated cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMed1992

Dobutamine stress echocardiography as a predictor of cardiac events associated with aortic surgery.

Two-dimensional echocardiography can detect regional wall motion abnormalities resulting from myocardial ischemia produced by dobutamine infusion. In 60 patients undergoing elective aortic surgery (27 with aneurysms, 33 with occlusive disease), we evaluated the ability of dobutamine stress echocardiography to predict perioperative cardiac events. Echo images were obtained at rest and during incremental dobutamine infusion to a peak dose of 50 micrograms/kg/min, unless another test end point was reached (angina, heart rate greater than or equal to 85% of age-predicted maximum, significant ST segment depression, or new stress-induced wall motion abnormalities). Dobutamine stress echocardiography results were stratified as follows: group I, no wall motion abnormalities; group II, resting wall motion abnormalities unchanged with stress; group III, stress-induced worsening of resting wall motion abnormalities; group IV, new-onset wall motion abnormalities with stress. Twelve cardiac events occurred within the first 30 postoperative days: three cardiac deaths (5%), six nonfatal myocardial infarctions (10%), two patients with unstable angina (3.3%), and one patient with asymptomatic elevation of creatine phosphokinase MB isoenzymes without electrocardiographic changes (1.7%). Eleven events occurred in the 38 patients with an abnormal dobutamine stress echocardiograph (groups II to IV); in contrast, only one of 22 patients with a normal dobutamine stress echocardiograph (group I) had a cardiac event. These event rates (29% vs 4.6%) differed significantly (p less than 0.025). Dobutamine stress echocardiography is a new, safe, rapid, relatively low cost, noninvasive, nonexercise cardiac stress test for risk stratification before major vascular surgery.

Aged↗
PubMed1992

Catecholamine stress echocardiography.

Two-dimensional echocardiographic monitoring during catecholamine infusion has shown promise as a safe and accurate method for detection of coronary artery disease. The clinical application of catecholamine stress echocardiography has been facilitated by the development of digital image processing techniques. The sensitivity of this method of stress testing has been improved by drug infusion protocols that are designed to maximize myocardial stress. Recent investigations have demonstrated the value of dobutamine stress echocardiography for detection of multivessel disease following myocardial infarction and for assessment of cardiac risk before noncardiac surgery. Evaluation of changes in wall motion and thickening that occur during low dose dobutamine infusion may enable detection of viable myocardium after thrombolytic treatment of acute myocardial infarction. Compared to alternative noninvasive diagnostic methods, catecholamine stress echocardiography permits continuous acquisition of high-quality information on regional and global systolic function. This and other advantages have prompted the search for broader applications of this technique.

Animals↗