End-systolic regional wall stress-length and stress-shortening relations in an experimental model of normal, ischemic and reperfused myocardium.

Assessment of left ventricular function is influenced by a number of hemodynamic factors. The purpose of this study was to evaluate the end-systolic regional wall stress-dimension relation in a series of 25 mongrel dogs. In Group A (n = 18) the regional wall stress-velocity of circumferential fiber shortening relation was measured before and after three interventions: volume infusion, metoprolol infusion and dobutamine infusion. The electrocardiogram, left ventricular pressure and its first derivative (dP/dt), arterial pressure and echocardiograms were recorded at baseline and after phenylephrine administration (to increase afterload). For each dog values for regional wall stress were plotted against the velocity of circumferential fiber shortening. For all dogs the relations were inversely linear (r = -0.65 to -0.98). Volume infusion increased end-diastolic volume (p less than 0.05) without shifting the slope or intercept of the relation, indicating its independence from preload. Dobutamine caused a shift in the intercept to the right but no change in slope and metoprolol shifted the relation to the left without altering the slope. The effect of ischemia and reperfusion on the end-systolic regional wall stress-length relation was examined in Group B (n = 7), at baseline, after 5 min of mid-left anterior descending coronary artery occlusion and after 10 min of reperfusion. Afterload was increased by hydraulic aortic occlusion. Regional wall stress was lowest at baseline, highest during ischemia and intermediate after reperfusion (100.2 +/- 32.1, 193.5 +/- 81.5, 141.9 +/- 67.6 kdyn/cm2, respectively, p less than 0.001). The end-systolic regional wall stress-length relation was linear during baseline, ischemia and reperfusion (r = 0.96, 0.95, 0.98, respectively, p less than 0.05). Ischemia caused an increase in the slope and a shift in the intercept to the right compared with baseline. Reperfusion represented an incomplete return toward baseline. This study demonstrates that the regional wall stress-velocity of circumferential fiber shortening relation is linear, independent of preload, incorporates afterload and is sensitive to changes in contractility. In addition, the regional wall stress-length relation can be measured in a nonhomogeneously contracting left ventricle and is predictably altered by ischemia and reperfusion. This relation may prove useful to determine whether alterations in regional systolic function result from changes in local load or contractility in the left ventricle with a regional wall motion abnormality.

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.

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.

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.

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.

Examination of racial differences in management of cardiovascular disease.

OBJECTIVES: We sought to identify the clinical characteristics associated with, and to investigate the impact of cohort selection criteria on, interracial use of invasive cardiac procedures and to determine survival. BACKGROUND: Although interracial differences in the use of invasive cardiac procedures have been previously reported, the underlying reasons are not known. METHODS: A retrospective cohort study was conducted at a Veterans Affairs Medical Center. Study patients were evaluated for cardiovascular disease between January 1 and December 31, 1993. RESULTS: The study included 1,406 male patients (85% white, 58% married), with a mean age of 63.4 years. African Americans were less likely than whites to undergo procedures (cardiac catheterization: odds ratio [OR] 0.37, 95% confidence interval [CI] 0.24 to 0.58; coronary angioplasty: OR 0.60, 95% CI 0.25 to 1.49; coronary bypass surgery: OR 0.22, 95% CI 0.08 to 0.63; any procedure: OR 0.32, 95% CI 0.21 to 0.50). On bivariate analysis, patients who underwent cardiac procedures were more likely to be younger, married and reside nonlocally and less likely to have severe comorbid disease; however, African Americans were less likely to be married and to reside nonlocally and more likely to have severe comorbid disease. Cohorts adjusting for referral status and specified cardiac diagnoses reduced or reversed interracial treatment differences. Thirty-day and 1-year survival rates (96% and 87.6%, respectively) were equivalent. CONCLUSIONS: Racial disparity in invasive cardiac procedure use may be partially explained by clinical differences and cohort selection bias. Despite treatment differences, survival rates were equivalent in African Americans and whites.

Improved left ventricular endocardial border delineation and opacification with OPTISON (FS069), a new echocardiographic contrast agent. Results of a phase III Multicenter Trial.

OBJECTIVES: The echocardiographic contrast-enhancing effects and safety profile of ALBUNEX (a suspension of air-filled albumin microspheres) were compared with the new contrast agent OPTISON (formerly FS069: a suspension of albumin microspheres containing the gas perfluoropropane) in 203 patients with inadequate noncontrast echocardiograms. BACKGROUND: The efficacy of ALBUNEX has been limited by its short duration of action. By using perfluoropropane instead of air within the microsphere, its duration of action is increased. METHODS: Each patient received ALBUNEX (0.8 and 0.22 mL/kg) and OPTISON (0.2, 0.5, 3.0, and 5.0 mL) on separate days a minimum of 48 hours apart. Echocardiograms were evaluated for increase in left ventricular (LV) endocardial border length, degree of LV opacification, number of LV endocardial border segments visualized, conversion from a nondiagnostic to a diagnostic echocardiogram, and duration of contrast enhancement. A thorough safety evaluation was conducted. RESULTS: Compared with ALBUNEX, OPTISON more significantly improved every measure of contrast enhancement. OPTISON increased well-visualized LV endocardial border length by 6.0+/-5.1, 6.9+/-5.4, 7.5+/-4.7, and 7.6+/-4.8 cm, respectively, for each of the four doses, compared with only 2.2+/-4.5 and 3.4+/-4.6 cm, respectively, for the two ALBUNEX doses (p < 0.001). 100% LV opacification was achieved in 61%, 73%, 87%, and 87% of the patients with the four doses of OPTISON, but in only 16% and 36% of the patients with the two ALBUNEX doses (p < 0.001). Conversion of nondiagnostic to diagnostic echocardiograms with contrast occurred in 74% of patients with the optimal dose of OPTISON (3.0 mL) compared with only 26% with the optimal dose of ALBUNEX (0.22 mL/kg) (p < 0.001). The duration of contrast effect was also significantly greater with OPTISON than with ALBUNEX. In a subset of patients with potentially poor transpulmonary transit of contrast (patients with chronic lung disease or dilated cardiomyopathy), OPTISON more significantly improved the same measures of contrast enhancement compared with ALBUNEX and did so to the same extent as in the overall population. Side effects were similar and transient with the two agents. CONCLUSION: OPTISON appears to be a safe, well-tolerated echocardiographic contrast agent that is superior to ALBUNEX.

Evaluation of patterns of perfusion and metabolism in dobutamine-responsive myocardium.

OBJECTIVES: We investigated the patterns of perfusion and metabolism in dysfunctional myocardium whose contractility improved with dobutamine. BACKGROUND: Clinical studies have suggested that dobutamine echocardiography can identify hibernating myocardium, but laboratory studies suggest that reduced perfusion limits the response to dobutamine. METHODS: Twenty-five patients with coronary disease and ventricular dysfunction underwent low (5 and 10 micrograms/kg body weight per min) and high dose (maximum of 50 micrograms/kg per min) dobutamine echocardiography and positron emission tomography (PET) using nitrogen-13 (N-13) ammonia and fluorine-18 fluorodeoxyglucose (FDG) for imaging of perfusion and metabolism. Wall motion and tracer uptake were scored in 16 left ventricular segments. RESULTS: Perfusion and metabolism were normal in 56.4%, mildly reduced in 29.1% and mismatched (reduced perfusion, preserved FDG uptake) in 14.5% of dysfunctional segments viable on PET. Wall motion improved with dobutamine in 89 dysfunctional segments (62 at low dose, 27 only at peak dose), and 86 of these (97%) were viable on PET. Improvement in wall motion with dobutamine was more common in segments with normal perfusion and metabolism (56.5%) than in those with mildly reduced tracer uptake (28.5%, p < 0.001) and those with mismatch (32%, p = 0.03). All the segments with a biphasic response were supplied by vessels with > or = 70% stenosis, and 88% had normal perfusion and metabolism. CONCLUSIONS: The majority of viable segments with rest dysfunction had normal perfusion and metabolism, suggesting that myocardial stunning was common. Improvement of wall motion at low and high doses of dobutamine was highly correlated with myocardial viability on PET and was more common in myocardium with normal perfusion. A biphasic response to dobutamine identified segments with normal perfusion and metabolism supplied by severely diseased vessels.

Phase III multicenter trial comparing the efficacy of 2% dodecafluoropentane emulsion (EchoGen) and sonicated 5% human albumin (Albunex) as ultrasound contrast agents in patients with suboptimal echocardiograms.

OBJECTIVES: This study was performed to compare the safety and efficacy of intravenous 2% dodecafluoropentane (DDFP) emulsion (EchoGen) with that of active control (sonicated human albumin [Albunex]) for left ventricular (LV) cavity opacification in adult patients with a suboptimal echocardiogram. BACKGROUND: The development of new fluorocarbon-based echocardiographic contrast agents such as DDFP has allowed opacification of the left ventricle after peripheral venous injection. We hypothesized that DDFP was clinically superior to the Food and Drug Administration-approved active control. METHODS: This was a Phase III, multicenter, single-blind, active controlled trial. Sequential intravenous injections of active control and DDFP were given 30 min apart to 254 patients with a suboptimal echocardiogram, defined as one in which the endocardial borders were not visible in at least two segments in either the apical two- or four-chamber views. Studies were interpreted in blinded manner by two readers and the investigators. RESULTS: Full or intermediate LV cavity opacification was more frequently observed after DDFP than after active control (78% vs. 31% for reader A; 69% vs. 34% for reader B; 83% vs. 55% for the investigators, p < 0.0001). LV cavity opacification scores were higher with DDFP (2.0 to 2.5 vs. 1.1 to 1.5, p < 0.0001). Endocardial border delineation was improved by DDFP in 88% of patients versus 45% with active control (p < 0.001). Similar improvement was seen for duration of contrast effect, salvage of suboptimal echocardiograms, diagnostic confidence and potential to affect patient management. There was no difference between agents in the number of patients with adverse events attributed to the test agent (9% for DDFP vs. 6% for active control, p = 0.92). CONCLUSIONS: This Phase III multicenter trial demonstrates that DDFP is superior to sonicated human albumin for LV cavity opacification, endocardial border definition, duration of effect, salvage of suboptimal echocardiograms, diagnostic confidence and potential to influence patient management. The two agents had similar safety profiles.

Racial disparity in cardiac decision making: results from patient focus groups.

BACKGROUND: While numerous studies suggest that African Americans receive fewer invasive cardiac procedures than whites, the basis for these treatment differences is not understood. METHODS: We conducted focus group sessions with patients who had received treatment in the hospital or the emergency department within the preceding 3 months for ischemic heart disease at 2 urban, university-affiliated hospitals. RESULTS: Discussions with patients identified the following factors that influenced their decision making: clarity, simplicity, and consistency of treatment recommendations; advice from friends and family about whether to accept recommendations; availability to speak with others who accepted similar recommendations; and having honest and caring physicians. African American patients identified the following additional factors that influenced their decision making: perceptions of health care discrimination; perceptions of undesirable physician behavior; faith in God to control one's destiny; and patient-physician camaraderie. CONCLUSIONS: Participants identified common issues influencing health care decision making, regardless of race. However, additional factors were expressed only by African American participants. These factors conveyed racial differences in perceptions of the health care system that may, in part, contribute to differences in health care decision making and treatment.

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.

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.

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.

Impact of B-mode color encoding on rapid detection of ultrasound targets: an in vitro study.

The purpose of this study was to assess the impact that new B-Mode color encoding schemes have on an observer's ability to rapidly detect ultrasound targets in an in vitro system. Four phantoms were created with five-, six-, or seven-tissue-density objects. Each phantom was scanned in routine grey scale (256 grey levels) and in three different color encoding algorithms. A test tape containing 3- and 5-second exposures, in random order, to the different phantoms recorded in grey and B-mode color was then prepared and viewed by 21 observers. Results were tabulated as the mean number of absolute errors in object recognition, per observer, per scan, for both the 3- and 5-second exposures. Each color scheme reduced observer detection error rates compared with error rates with grey scale recordings when viewed for 3 seconds. There was no reduction in error rates when 5-second exposures were viewed. We conclude that in an in vitro system, new B-mode color encoding schemes may facilitate rapid and accurate detection of soft-tissue targets.

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.

Comparison of digital with videotape echocardiography in patients with chest pain in the emergency department.

We prospectively compared digital echocardiographic images, by a minimal digital-acquisition strategy, with videotape images to determine the diagnostic utility of digital imaging in patients admitted to the emergency department with chest pain. Digital acquisition has many potential advantages for evaluating echocardiographic images, especially in the acute-care setting. It is not yet known how much the imaging study can be condensed with digital technology and still provide the necessary information needed for clinical echocardiographic diagnosis. One hundred seventeen patients with diagnoses consisting of coronary artery disease, pericardial disease, and valvular disease were studied. Overall agreement between videotape and digital recordings with regard to normal versus abnormal wall motion was 94% (p < 0.001). The wall motion score index, a semiquantitative measure of global function, also correlated well (r = 0.94). Complete concordance was noted in all patients with aortic stenosis and pericardial effusion. Digital echocardiographic imaging, by a minimal-acquisition strategy, is an accurate summary of the complete echocardiographic examination and provides the relevant diagnostic data needed for the assessment of patients with chest pain in the emergency department.

Intracardiac echocardiography-guided biopsy of intracardiac masses.

A 69-year-old man diagnosed with lung cancer had a transesophageal echocardiogram performed because of suspicion of intramyocardial tumor. The transesophageal echocardiogram confirmed the presence of both a right and left atrial mass. The lung cancer was believed to be potentially resectable if this mass did not represent tumor; therefore, biopsy of the intracardiac mass was requested. Intracardiac ultrasound was used to guide the biopsy procedure. Using intracardiac ultrasound guidance, a successful biopsy was performed that revealed the presence of tumor cells.

Pharmacologically induced myocardial ischemia: a comparison of dobutamine and dipyridamole.

The purpose of our study was to compare the ability of dobutamine and dipyridamole infusion to induce myocardial ischemia. In a population of 16 anesthetized open-chest swine, a coronary artery stenosis sufficient to abolish the hyperemic response to a 15-second total occlusion was created. Heart rate, systolic blood pressure, and dP/dt were recorded. Myocardial segment shortening was determined by sonomicrometry in all animals. In a subset of seven animals regional myocardial blood flow was measured by injection of radiolabeled microspheres. Dipyridamole was infused according to a high-dose protocol. After a washout period and reestablishment of a baseline state, dobutamine was infused incrementally. There was no significant difference between the baseline states. Dipyridamole did not affect heart rate but did significantly decrease blood pressure and rate-pressure product. Myocardial segment shortening decreased in the ischemic zone by 0.07 +/- 0.08 (p = 0.004). Dobutamine infusion significantly increased heart rate, blood pressure, and rate-pressure product. Myocardial segment shortening in the ischemic zone decreased by 0.17 +/- 0.09 (p < 0.001). Dobutamine decreased blood flow in the ischemic zone relative to baseline. Both dobutamine and dipyridamole infusion resulted in myocardial ischemia. The magnitude of the ischemic response is greater for dobutamine than for dipyridamole.

Transthoracic echocardiographic power motion tissue imaging of an intracardiac tumor that could not be seen with conventional transthoracic echocardiographic recordings.

Power motion imaging allows interrogation of low-velocity tissue. By means of power motion imaging with 2 different late-model echographs we identified an intra-atrial tumor that was undetectable on conventional transthoracic echocardiograms.

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.