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Cardiovascular stress testing remains the mainstay of provocative evaluation for patients with known or suspected coronary artery disease. Stress echocardiography has become a valuable means of cardiovascular stress testing. It plays a crucial role in the initial detection of coronary disease, in determining prognosis, and in therapeutic decision making. The purpose of this document is to outline the recommended methodology for stress echocardiography with respect to personnel and equipment as well as the clinical use of this recently developed technique. Specific limitations will also be discussed.

This symposium focuses on the basic and advanced methodology of stress echocardiography and outlines its applications and clinical impact as they relate to the evaluation of patients in a contemporary cardiology practice. This section deals with the history of the technique, the theory behind its development, and the methodology of the various stress echocardiography techniques. Subsequent sections will deal with its accuracy for identifying coronary artery disease in patients with chest pain syndromes, its utility as a prognostic tool, its use in patients with valvular disease, pulmonary hypertension, and other noncoronary syndromes, and finally, new uses such as the evaluation of myocardial viability.

Preamble It is clearly important that the medical profession plays a significant role in critically evaluation of the use of diagnostic procedures and therapies in the management or prevention of disease. Rigorous and expert analysis of the available data documenting relative benefits and risks of those procedures and therapies can produce helpful guidelines that …

Doppler tissue imaging (DTI) is a new noninvasive imaging modality that directly interrogates myocardial velocity with high temporal and spatial resolution. This study was designed to test the hypothesis that quantitative DTI provides unique information regarding regional myocardial systolic and diastolic function during acute ischemic events. Myocardial velocities were quantified during the acute ischemic and reperfusion phases of 13 elective percutaneous coronary angioplasty procedures in 12 patients. In myocardium subtended by angioplasty vessels, peak velocities decreased during occlusive balloon inflation (from 21.2 +/- 9.8 to -0.6 +/- 4.0 mm/sec in systole [p < 0.001] and from 21.7 +/- 9.2 to -0.6 +/- 3.9 mm/sec in diastole [p < 0.001]). During early reperfusion, velocities exceeded those observed at baseline (p = 0.003). In regions remote from the treated artery, peak myocardial velocities increased in the absence of significant stenosis but remained unchanged or decreased in the presence of significant stenosis of the associated vessel. We conclude that (1) myocardial velocities rapidly decrease during acute ischemia and show a rebound increase after reperfusion, and (2) in regions remote from ischemia, velocities display distinct patterns on the basis of the presence or absence of obstructive coronary disease in the associated vessel. Quantitative DTI is a useful tool for the assessment of myocardial velocity and may provide new insights into myocardial systolic and diastolic function.

Although the accuracy of dobutamine stress echo (DSE) for detecting coronary artery disease (CAD) has been established, its role in determining prognosis is less well defined. The purpose of this study was to evaluate the prognostic significance of DSE in patients with known or suspected CAD. Follow-up was obtained on 291 patients an average of 15 months after clinically indicated DSF. Studies were stratified with respect to resting and inducible wall motion abnormalities into 1 of 4 responses: normal, ischemic, fixed, and mixed. Hard end points of nonfatal myocardial infarction and cardiac death were tabulated for outcome. Statistically significant differences in the incidence of hard cardiac end points were noted for 2 of 4 DSE responses. A normal DSE was associated with a statistically lower likelihood of a hard cardiac event than was a DSE demonstrating resting or inducible abnormalities (p = 0.001). DSE with a mixed response (resting abnormality with additional inducible ischemia) was associated with a higher likelihood of cardiac events by multivariate analysis (p = 0.003). By multiple logistic regression analysis of dobutamine response, age, and cardiac risk factors, only a mixed response on DSE was independently associated with the occurrence of a hard cardiac event in the follow-up period. In addition, left ventricular dysfunction on the resting echocardiogram was associated with a worse prognosis in patients with major noncardiac disease. We conclude that dobutamine response is an independent predictor of cardiac events compared with traditional risk factor analysis and that DSE can identify high- and low-risk subsets of patients with known or suspected CAD. (Am J Cardiol 1996;78:404–408)

Chronic ischemic dysfunction of the left ventricle is commonly presumed to represent “hibernating” myocardium. The implication of this assumption is that with successful reperfusion, systolic function will improve. Several diagnostic techniques including dobutamine stress echocardiography have been used to detect “viable” myocardium in the setting of chronic left ventricular dysfunction. Predictive accuracies of 70% to 85% have been reported for identifying myocardium that recovers function. Recovery of function has been variable and often dependent on the severity of dysfunction. All current models have presumed that chronically dysfunctioning myocardium is “hibernating.” Obviously, in the chronic setting, dysfunction may have many causes and include components of transmural and nontransmural infarction as well as hibernating myocardium. This review focuses on the independent role that nontransmural infarction may play in chronic dysfunction and suggests its impact on diagnostic techniques used to identify hibernating myocardium.

Summary Doppler tissue imaging is a novel means of imaging that interrogates high amplitude, low velocity echoes in the range of tissue and myocardial motion. In addition to providing a qualitative aid in edge detection and wall motion analysis, quantitative interrogation of myocardial velocities may provide insights into normal and abnormal systolic and diastolic ventricular function. The technique and applicability of Doppler tissue imaging will continue to evolve with ongoing advances in imaging hardware and software.

Objectives. This study sought to determine the efficacy and safety of arbutamine echocardiography in inducing myocardial ischemia and detecting coronary artery disease. Background. Exercise and pharmacologic stress echocardiography are clinically accepted techniques for detecting coronary artery disease. Arbutamine is a new synthetic beta-adrenoceptor agonist developed specifically as a stress agent. Arbutamine is delivered by a new computerized drug delivery device that adjusts the rate of drug infusion according to the patient's heart rate response during stress testing. Methods. The sensitivity of arbutamine echocardiography was determined in 143 patients who had coronary artery disease documented by coronary angiography. A subset of these patients (n = 114) also underwent exercise echocardiography. The specificity, or normalcy, of arbutamine echocardiography was determined in 54 patients considered to have a low likelihood of coronary artery disease. Results. Among those patients who had both stress test results, the incidence of inducing myocardial ischemia (new or worsening wall motion abnormalities) was 79% (95% confidence interval [ci]69% to 86%, n = 98) for arbutamine and 77% (95% CI 67% to 85%, n = 98) for exercise echocardiography. The sensitivity of detecting coronary artery disease (ischemia or rest wall motion abnormality) was 87% (95% CI 79% to 93%, n = 101) for arbutamine and 83% (95% CI 74% to 90%, n = 101) for exercise echocardiography. The specificity (normalcy) of arbutamine echocardiography was 96% (95% CI 87% to 100%, n = 52). Arbutamine was well tolerated, and there were no serious adverse events. Conclusions. Arbutamine echocardiography is an effective and safe pharmacologic stress test technique for diagnosing or excluding the presence of coronary artery disease. The ability of arbutamine stress to induce myocardial ischemia, detectable by echocardiography, was comparable to that for exercise.

Doppler tissue imaging (DTI) is a new echocardiographic imaging technique from which quantitative data regarding myocardial velocity can be extracted. The purpose of this study was to compare endocardial velocities determined from DTI with those determined from M-mode echocardiography and to assess the range of myocardial velocities in normal subjects. Nineteen subjects were evaluated by M-mode echocardiography and quantitative DTI for maximal systolic velocities of the anteroseptal and inferoposterior walls. Mid-myocardial and epicardial velocities were also measured by DTI for each wall. Maximal systolic velocities of the anteroseptal and inferoposterior endocardium determined by DTI correlated significantly with those derived from M-mode echocardiography (r = 0.87). The velocity of the inferoposterior wall by DTI (27.3 +/- 4.8 mm/sec) was greater than that of the anteroseptum (20.8 +/- 4.1 mm/sec) by a mean difference of 7.0 +/- 5.7 mm/sec (p0.001). A peak velocity gradient of 5.9 +/- 3.5 mm/sec (p0.001) between the epicardium to endocardium was detected. These data confirm that (1) regional myocardial velocities may be quantified with DTI in human beings; (2) the high resolution of DTI allows velocities to be determined at different levels within the myocardium; and (3) heterogeneity of myocardial velocities may be demonstrated in normal subjects.

Objectives. This study was designed to characterize the clinical, echocardiographic and angiographic findings in patients who have regional wall motion abnormalities predictive of coronary artery disease on dobutamine stress echocardiograms, although coronary angiography reveals no critical stenoses. Background. The specificity of dobutamine stress echocardiography has been reported to be lower than its sensitivity; the sources of false positive findings on dobutamine stress echocardiograms have not been previously defined. Methods. Clinical and echocardiographic characteristics were retrospectively reviewed for patients who had both a dobutamine stress echocardiogram indicate of coronary artery disease on the basis of wall motion abnormalities and

We describe the clinical and echocardiographic findings in eight patients with right atrial spontaneous echo contrast who were identified from 648 consecutive patients undergoing transesophageal echocardiography. Common findings in these patients were right atrial enlargement (8 patients), tricuspid regurgitation (7 patients), atrial fibrillation or flutter (6 patients), elevated right ventricular pressure (5 patients), moderate or severe mitral valve disease (5 patients), and right to left interatrial shunts (3 patients). Right heart catheterization in three patients showed markedly elevated right atrial, right ventricular, and pulmonary artery pressures. Two patients had thromboembolic events-one patient had recurrent pulmonary emboli, and another patient with an atrial septal aneurysm had recurrent transient ischemic attacks. Right atrial echo contrast is an uncommon finding at echocardiography that is associated with severe right heart dysfunction. It may also be associated with paradoxical or pulmonary embolism.

Positron emission tomography-derived 11C-labeled acetate kinetics have been shown to reflect myocardial oxidative metabolism. The objective of the study was to use this metabolic imaging technique in combination with an evaluation of left ventricular work as an index of ventricular mechanical efficiency.The effects of ventricular ejection fraction and loading on this index were studied quantitatively in a canine experimental model. There was a curvilinear relationship between efficiency and the end-diastolic volume per unit mass (r = 0.84), which appeared to integrate the main determinants of left ventricular mechanical performance successfully and allowed the detection of a decreased ventricular efficiency in acute experimental heart failure.This approach appears to have the potential to assess the energetic working point of the ventricle in clinical heart disease and follow the effects of therapy. The data demonstrate the feasibility of an estimate of ventricular efficiency that relies on noninvasive data-acquisition techniques.

Frequent idiopathic premature ventricular complexes (PVCs) can result in a reversible form of cardiomyopathy. In this study, the determinants of PVC-induced left ventricular (LV) dysfunction were assessed.The subjects of this study were 241 consecutive patients (115 men [48%], mean age 48 ± 14 years) referred for ablation of frequent PVCs. One hundred eighty patients (75%) experienced palpitations and 61 (25%) did not. The PVC burden was determined by 24-hour Holter monitoring, and echocardiograms were performed to assess LV function. An LV ejection fraction of50% was considered abnormal.LV ejection fraction (mean 0.36 ± 0.09) was present in 76 of 241 patients (32%). There was a higher prevalence of males among the patients with PVC cardiomyopathy compared to patients with normal LV function (51/76 [67%] vs 64/165 [39%]; P.0001). The mean PVC burden was significantly higher in patients with PVC cardiomyopathy than in patients with normal LV function (28% ± 12% vs 15% ± 13%; P.0001). Among symptomatic patients, those with cardiomyopathy had a significantly longer duration of palpitations (135 ± 118 months) compared with patients with normal LV function (35 ± 52 months; P.0001). The proportion of asymptomatic patients was significantly higher in the presence of cardiomyopathy (36/76, 47%) than in normal LV function (25/165, 15%; P.0001). Symptom duration of 30 to 60 months, symptom duration60 months, the absence of symptoms, and the PVC burden in asymptomatic patients were independent predictors of impaired LV function (adjusted odds ratio [95% confidence interval]: 4.0 [1.1-14.4], 20.1 [6.3-64.1], 13.1 [4.1-37.8], and 2.1 [1.2-3.6], respectively).The duration of palpitations and the absence of symptoms are independently associated with PVC-induced cardiomyopathy.

Objectives. The aim of this study was to use positron emission tomography (PET)-derived carbon (C)-11 acetate kinetics to determine the effects of dobutamine on oxidative metabolism and its effects on myocardial efficiency in a group of patients with dilated cardiomyopathy. Background. Dobutamine is known to improve myocardial function but may do so at the expense of myocardial oxygen consumption, which could be a potential deleterious effect. Carbon-11 aceate kinetics correlate with myocardial oxygen consumption as shown in animal models. Combining these scintigraphic measurements of oxygen consumption with estimates of cardiac work results in a work-metabolic index, which reflects cardiac efficiency. Methods. Eight patients with nonischemic dilated cardiomyopathy underwent dynamic PET imaging, echocardiography and hemodynamic measurements. Seven of these patients were also studied while receiving dobutamine. Direct measurements of myocardial oxygen consumption using coronary sinus catheterization were obtained with eight of the PET studies to validate C-11 acetate in patients with cardiomyopathy. Results. The mean (± SD) C-11 clearance rate significantly increased with dobutamine from 0.105 ± 0.027 to 0.155 ±0.023 min−1(p = 0.001). Directly measured myocardial oxygen consumption had a linear relation to the mean C-11 clearance rate (r = 0.8, p = 0.018). Dobutamine was noted to significantly reduce systemic vascular resistance as well as the severity of mitral regurgitation. The work-metabolic index determined using hemodynamic variables and PET data increased from 2 ± 0.7 × 104to 2.6 ± 0.6 × 104(p = 0.04). Efficiency, estimated by employing the oxygen consumption to k2relation, also increased from 13 ± 4.5% to 16.9 ± 6.4% (p = 0.04). Conclusions. Despite an increase in myocardial oxygen consumption, dobutamine led to an increase in work-metabolic index in patients with dilated nonischemic cardiomyopathy. Dobutamine reduced systemic vascular resistance and mitral regurgitation, suggesting that in this group of patients, it had important vasodilatory action in addition to its inotropic effects. The use of the C-11 acetate PET for determining myocardial oxygen consumption and estimating efficiency could potentially complement existing clinical measures of ventricular performance and may allow improved and objective evaluation of therapy in patients with heart failure.

The problems of population referral bias in the calculation of specificity in diagnostic testing for coronary artery disease have been previously described. Previous studies investigating the sensitivity and specificity of dobutamine stress echocardiography (DSE) have been subject to pretest and posttest referral biases, largely as a result of the requirement for coronary arteriography. This study determines the normalcy rate for DSE by examining a population at statistically low risk for coronary artery disease. The probability of significant coronary artery disease was determined for 828 consecutive patients referred for DSE at the University of Michigan, and groups were identified with10% and5% probability of disease. Four of 72 patients (5.6%) with a normal baseline echocardiogram and a probability of coronary artery disease of10%, and three of 38 (7.9%) with a probability of5% were found to have an abnormal DSE, yielding normalcy rates of 94.4% and 92.1%, respectively. The area of abnormality involved the posterior circulation in three of four patients (75%). This study demonstrates that DSE has a normalcy rate of 92% to 94% and is an accurate test for excluding the presence of significant coronary artery disease.

investigated formally, we are unaware of any specific predisposing factors for the development of SANRT in these patients. All 5 patients had placement of atrial cannulas in standard fashion in the right atrial appendage, whereas the 4 patients undergoing Norwood I had concomitant standard atrial septectomy. However, given the association with hypoplastic left heart syndrome, one must wonder if there is an inherent abnormality of the sinus node that predisposes these patients to SANRT.

Training in clinical cardiac electrophysiology should take place in an Accreditation Council for Graduate Medical Education accredited cardiology program, and the electrophysiology training program itself should be accredited by the Council. Each trainee must be eligible for board certification in Internal Medicine and either eligible for certification in Cardiovascular Diseases or in a program leading to eligibility. Training faculty should be certified in clinical cardiac electrophysiology or demonstrate equivalent credentials. At least two training faculty members are preferred. The faculty must be dedicated to teaching, active in performing or promoting research and must spend a substantial portion of their time in research, teaching and practice of clinical electrophysiology. A curriculum of training should be established. Faculty experts in the related basic sciences should be available and involved in teaching. The institution should have a fully equipped clinical electrophysiology laboratory and complete noninvasive capabilities. A close working relation with a cardiac surgery faculty member skilled in surgical treatment of arrhythmias is required. Training in application of pharmacologic and all current nonpharmacologic therapies, in the outpatient and inpatient setting, is necessary. The clinical exposure must include all facets of arrhythmia diagnosis and treatment and must be quantitatively sufficient to allow the trainee to develop proficiency. The period of training should not be less than one year in addition to the period of cardiology fellowship required by the ABIM for board eligibility. A continuous period of training is preferred.

BACKGROUND Two-dimensional echocardiography performed during dobutamine infusion has been 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 RESULTS In this study, echocardiograms were recorded during step-wise infusion of dobutamine to a maximum dose of 30 micrograms/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 (greater than or equal to 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. CONCLUSIONS Echocardiography 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.

Myocardial contrast echocardiography has been found to be a safe and useful technique for evaluating relative changes in myocardial perfusion and delineating areas at risk. Although earlier contrast agents required direct delivery into the coronary arteries or aortic root, a new echocardiographic contrast agent, sonicated albumin microspheres (Albunex), has been found to cross the pulmonary circulation in experimental models.To determine the safety and preliminary efficacy of intravenous injections of Albunex in humans, 71 patients at three independent medical institutions underwent two-dimensional echocardiographic examination before, during and after the administration of three intravenous doses of Albunex, ranging from 0.01 to 0.12 ml/kg body weight. All patients provided a complete history and underwent physical and neurologic examination and laboratory and electrocardiographic evaluation before the injections; all evaluations (except for the history) were repeated at 2 h and 3 days after the injections of Albunex. The efficacy of the injections was qualitatively assessed by two independent blinded observers using a grading system of 0 to + 3, with 0 indicating an absence of contrast effect and + 3 indicating full opacification of the cavities examined.All injections were well tolerated and no serious side effects were noted in any of the patients. Irrespective of dose group, a cavity opadfication ≥ + 2 was seen in the right ventricle in 212 (88%) of 240 injections and in the left ventricle in 151 (63%) of 240 injections as judged by the independent observers. The degree of ventricular cavity opacification appeared to be dose and concentration related. In conclusion, this first multicenter clinical study of Albunex demonstrates that the contrast agent is safe when administered Intravenously and achieves significant transpulmonary passage in a majority of patients.

Aortic dissection is a catastrophic medical emergency if not recognized early and treated promptly. There is no survival study of untreated dissection to assess the natural history. Nevertheless, the prognosis has been shown to be poor Open image in new window Figure 4.1. This bar graph demonstrates the Stanford surgical mortality for aortic dissection from 1963 to 1992. There is a small but no significant improvement over the past 30 years despite significant improvement in surgical techniques. Reprinted with permission, from reference 2. for untreated aortic dissection1. Advances in the diagnosis of aortic dissection along with early medical and surgical treatments have had a significant impact on the outcome. However, this has plateaued over the last two decades tikya 2. Advances in the imaging technology have allowed improved diagnosis of this entity3, 4, 5, 6, 7, 8. However, the myriad presentations of this disease9, 10 and the spectrum of pathology with atypical features on the imaging modality11 have often delayed its recognition. Unless a high index of suspicion exists, the diagnosis may not be made early enough to avoid the catastrophic natural history.

To detect specific cardiomyocyte injury induced by myocardial contrast material-enhanced echocardiography (ie, myocardial contrast echocardiography) in rats and to ascertain the influences of contrast material dose and ultrasound exposure on this injury.All animal procedures were approved by the university committee for the use and care of animals. Myocardial contrast echocardiography with 1:4 electrocardiographic (ECG) triggering was performed at 1.5 MHz in 61 anesthetized rats. Evans blue (EB) dye was injected as the vital stain for cardiomyocyte injury. At the start of myocardial contrast echocardiography, which lasted 10 minutes, perflutren lipid microsphere-based contrast material was infused through the tail vein for 5 minutes. Premature heartbeats were counted from the ECG record. The numbers of EB-stained cells counted on sections of heart specimens obtained 24 hours after myocardial contrast echocardiography and then either fresh frozen or embedded in paraffin were determined by using fluorescence microscopy. Results were compared statistically by using t tests and Mann-Whitney rank sum tests.EB-stained cells were concentrated in the anterior region of the myocardium. In the paraffin-embedded specimens, EB-stained cells were often accompanied by but largely separate from areas of inflammatory cell infiltration. At end-systolic triggering with a 50 microL/kg dose of microsphere contrast material, the EB-stained cell count increased with increasing peak rarefactional pressure amplitude, with significantly increased cell counts at 1.6 MPa (P.02) and 2.0 MPa (P.005) relative to the cell counts at sham myocardial contrast echocardiography. Premature heartbeats had a similar exposure-response relationship; however, number of premature heartbeats and EB-stained cell count did not appear to be directly related (coefficient of determination r2 = 0.03). The EB-stained cell counts at end-diastolic triggering were not significantly different from those at end-systolic triggering (P.1). EB-stained cell counts increased with increasing contrast material dose, from 10 to 50 microL/kg, at 2.0 MPa.Cardiomyocyte injury was induced by the interaction of ultrasound pulses with contrast agent microbubbles during myocardial contrast echocardiography in rats, and the numbers of injured cells increased with increasing contrast agent dose and ultrasound exposure.

Background: During cardiac resynchronization therapy (CRT), cardiac performance is dependent on an optimized atrioventricular delay (AVD). However, the optimal AVD at different heart rates has not been defined yet during CRT. Method: The effects of an increase in heart rate by pacing or physical exercise on optimal AVD were studied in 36 patients with biventricular pacemakers/defibrillators. The velocity time integral (VTI) in the left ventricular outflow tract (LVOT) was measured with pulsed Doppler either at three different paced heart rates in the supine position or in seated position before and after physical exercise. Results: The baseline AVD was optimized to 99 ± 19 ms in the supine and 84 ± 22 ms in the seated position. When the heart rate was increased by DDD pacing, there was a positive linear relationship between an increase in heart rate, in AVD and in VTI (LVOT-VTI + 0.047 cm/s per 10 beats per minute (bpm) heart rate increase per 20 ms increase in AVD, P = 0.007). A similar but more pronounced relationship was found after physical exercise in the seated position (LVOT-VTI + 0.146 cm/s per 10 bpm heart rate increase per 20 ms increase of AVD, P = 0.013). This effect was observed in patients with and without AV block and mitral regurgitation. Conclusions: In conclusion, the systolic performance of the dilated ventricle, which depends on an elevated preload, is critically affected by the appropriate timing of the AVD during exercise. In contrast to normal pacemaker patients, in CRT the relatively short baseline AVD should be prolonged at increased heart rates. Further studies with other means of measuring exercise cardiac performance are needed to confirm these unexpected findings.

Continuous wave Doppler measurement of prosthetic valve gradients correlate with gradients obtained by cardiac catheterization for most prostheses. 1 For mechanical valves and prostheses with smaller and multiple orifices, however, significant discrepancies between Doppler-derived and catheter gradients have been reported. 2, 3 Transvalvular gradients in excess of 50mm Hg exist in approximately 10% of patients with normally functioning aortic prostheses. 4 This apparent "overestimation" of the transvalvular gradient by continuous wave Doppler has been attributed to the effects of localized pressure gradients and pressure recovery. 3 Overestimation of gradients caused by pressure recovery may lead to the erroneous diagnosis of prosthetic valve dysfunction. To circumvent potential errors in measurement of prosthetic valve gradients, it may be possible to estimate transvalvular gradients with indirect measurements of left ventricular and aortic systolic pressures. The approach used to estimate the left ventricular systolic pressure (LVSP) is based on the common echocardiographic practice used to determine right ventricular systolic pressure from the jet of tricuspid regurgitation. 5 In this case peak velocity of the mitral regurgitant (MR) jet obtained by continuous wave Doppler is used as an index of the gradient between the left ventricle and the left atrium (APLv-LA). This gradient, when added to a presumed left atrial pressure (LAP), results in an estimation of the LVSP (LVSP = LAP + APLv_LA). Left atrial pressure is assumed at 15 mm Hg, an estimate that would be expected to result in only minimal error for most patients. The aortic systolic pressure (Ao P) is estimated from the blood pressure recorded noninvasively in the brachial artery. The estimated LVSP and Ao P are then used to calculate a pressure gradient between the left ventricle and aorta, thereby avoiding the inherent problems associated with Doppler gradients across prosthetic valves. This approach requires that the jet of MR be of sufficient strength to accurately measure velocity. It has been well established that low concentrations of transpulmonary contrast agents enhance both spectral and color Doppler signals in the left heart. 6 Simultaneous administration of intravenous sonicated albumin for potentiation of the mi

Stress echocardiography is commonly employed for the clinical management of known or suspected coronary artery disease. This review discusses the accuracy of the technique, which is equivalent to that of competing imaging techniques, as well as its overall role in patient management. The utilization of stress echocardiographic modalities in clinical presentations, such as chest pain, congestive heart failure, and valvular heart disease, and preoperative risk assessment, as well as determining myocardial viability, are discussed.

Objectives We examined the feasibility of transesophageal echocardiography (TEE) using a 10F monoplane probe developed for intracardiac ultrasound (AcuNav, Acuson/Siemens, Mountain View, Calif). Background Traditional TEE uses a 10- to 12-mm–diameter probe, and conscious sedation is customary to minimize patient discomfort. Because of its small size (3.2-mm diameter), the 10F monoplane probe can be inserted into the esophagus using only topical anesthesia. This provides the potential for a more easily tolerated examination. Methods A total of 20 patients underwent a comprehensive TEE using an adult multiplane probe. Immediately afterward, the 10F monoplane probe was inserted into the esophagus and a targeted examination completed. The 10F monoplane studies were blindly reviewed by 3 observers for the study indication and for 16 diagnostic elements. These were graded against an expert's review of standard TEE. Results The 10F monoplane probe was well tolerated in all patients. Observers A, B, and C answered the clinical question in 80%, 85%, and 100%, respectively, with the 10F probe. The percentage of clinical elements deemed evaluable was 71%, 78%, and 80%, respectively. Limitations included incomplete visualization of the mitral valve and a systematic underestimation of the severity of valve regurgitation. Conclusions The 10F monoplane probe is safe, well-tolerated, and capable of evaluating many clinical questions. Because of its small size, conscious sedation may not be necessary. It may be useful for targeted evaluations, for monitoring invasive procedures, or for intermediate or long-term monitoring in an intensive care department.

Background: Patients hospitalized in medical ICUs (MICUs) with acute noncardiac illnesses have an undefined prevalence of underlying cardiovascular abnormalities. Because of the acuteness of illness, the need for frequent concurrent mechanical ventilation, and the nature of the underlying diseases, routine cardiac examination may be suboptimal for identifying concurrent cardiac abnormalities. Purpose: The purpose of this study was to utilize transthoracic echocardiography and Doppler echocardiography interrogation to identify the range and prevalence of occult cardiac abnormalities that may be present in patients admitted to an MICU. Methods: Over a 12-month period, 500 consecutive patients who had been admitted to the MICU of a large university tertiary care center underwent complete two-dimensional echocardiography and Doppler scanning within 18 h of admission. The final study population comprised 467 patients. No study subject had been admitted to the MICU for a primary cardiac diagnosis. Cardiovascular abnormalities were prospectively defined, and all echocardiograms were interpreted independently by blinded observers. Both MICU and overall mortality rates as well as length of stay were compared to the presence or absence of cardiac abnormalities. Results: One or more cardiac abnormalities was noted in 169 patients (36%). The average (SD) age of patients in the study was 52 17 years (age range, 17 to 100 years), and the average age was 57 18 years (age range, 18 to 93 years) in patients with underlying cardiac abnormalities. A single cardiac abnormality was noted in 103 patients (22%), two cardiac abnormalities were noted in 34 patients (7.2%), and three or more cardiac abnormalities were noted in 32 patients (6.8%). Based on subsequent requests for cardiac diagnostic studies, 67 patients (14.3%) were clinically suspected of having significant cardiovascular abnormalities, 39 of whom (58%) had one or more cardiac abnormalities on seen on echocardiography. Cardiac abnormalities were unsuspected in 130 of 169 patients (77%) and were only noted at the time they underwent surveillance echocardiography. Although there was no correlation between the presence of cardiac abnormalities and mortality, both MICU and hospital length of stay were increased in patients with cardiac abnormalities. Conclusion: A significant proportion of patients admitted to an MICU with noncardiac illness have underlying cardiac abnormalities, which can be detected with surveillance echocardiography at the time of admission. Cardiac abnormalities were associated with an increased length of stay but not with increased mortality. (CHEST 2002; 122:1370 –1376)

Mitral regurgitation (MR) and tricuspid regurgitation (TR) frequently develop in patients with left ventricular systolic dysfunction (LVSD). Ventricular volume overload that occurs in patients with MR and TR may lead to progression of myocardial dysfunction. We hypothesized that MR and TR would provide markers of risk in patients with LVSD.We reviewed clinical, electrocardiographic, and echocardiographic data on 1421 consecutive patients with LVSD (left ventricular ejection fractionor =35%). Predictors of survival (freedom from death or United Network for Organ Sharing [UNOS]-1 transplantation) were identified in a multivariable analysis with a Cox proportional hazards analysis. The impact of MR and TR (none to mild, moderate, or severe) then was assessed separately with Kaplan-Meier survival analysis.During the follow-up period (mean +/- SD, 365 +/-364 days), death occurred in 435 study subjects (31%) and UNOS-1 transplantation in 28 subjects (2%). Multivariable predictors of poor outcome included increasing MR and TR grade, cancer, coronary artery disease, and absence of an implantable cardiac defibrillator. Relative risk was 1.84 (95% CI 1.43-2.38) for severe MR and 1.55 (95% CI 1.14-2.11) for severe TR. Survival with Kaplan-Meier analysis related inversely to MR grade (none to mild 1004 +/-31 days, moderate 795 +/-34 days, severe 628 +/-47 days, P.0001) and TR grade (none to mild 977 +/-28 days, moderate 737 +/-40 days, severe 658 +/-55 days, P =.0001).Patients with severe MR or TR represent high-risk subsets of patients with LVSD. Future study is warranted to determine whether pharmaceutical or surgical strategies to relieve MR and TR have a favorable impact on survival.

Study objective: We assess an alternative accelerated clinical pathway approach to the management of patients with newly diagnosed or new-onset atrial fibrillation (AF). Methods: A prospective, randomized pilot study of 2 AF disease-management strategies was conducted at a single university hospital. A traditional approach of hospital admission versus an accelerated emergency department–based strategy with low-molecular-weight heparin and early cardioversion to sinus rhythm was assessed in a cohort of patients with uncomplicated AF. The primary end points were length of stay and total actual direct costs. Results: Eighteen patients were randomized over a 15-month period. The accelerated treatment strategy in the ED resulted in a substantial decrease in length of stay (2.1±2.3 versus P =.15). The clinical outcomes (rate of sinus rhythm at discharge and follow-up and complications caused by AF) related to AF were similar in the 2 groups. Conclusion: A disease-management strategy for new, uncomplicated AF that uses an ED-outpatient treatment pathway results in a shorter length of stay at potentially lower cost. The results of this pilot study warrant further investigation. [Kim MH, Morady F, Conlon B, Kronick S, Lowell M, Bruckman D, Armstrong WF, Eagle KA. A prospective, randomized, controlled trial of an emergency department–based atrial fibrillation treatment strategy with low-molecular-weight heparin. Ann Emerg Med. August 2002;40:187-192.]

Given the difference in risk factors, clinical presentation, and outcomes, clinicians should be vigilant for the presence of iatrogenic AD, particularly in those patients with unexplained hemodynamic instability or myocardial ischemia following invasive vascular procedures or CABG.

Triggered myocardial contrast echocardiography (MCE) has been used successfully to quantify myocardial blood flow and assess coronary stenosis in animal models, but practical considerations have limited its broad clinical use. Real-time MCE may have practical advantages to assess perfusion and real time myocardial blood flow in human beings. We compared real-time MCE with triggered imaging in 23 normal human volunteers by using an investigational ultrasound contrast agent (DMP-115) and a commercially available ultrasound platform (Acuson Sequoia). Peak myocardial opacification (reflecting myocardial blood volume) after contrast infusion was quantified digitally in gray scale units (GU). In 13 subjects, myocardial blood flow reserve was assessed during dipyridamole infusion with the use of intermittent destruction-replenishment techniques. Real-time MCE resulted in a 30- to 45-GU increase from baseline compared with a 20- to 70-GU increase with triggered imaging. Real-time MCE showed no statistical difference in opacification (P = .131 by analysis of variance) among any of the myocardial regions of interest. Triggered imaging resulted in heterogeneous opacification among the regions of interest (P.05 by analysis of variance). Dipyridamole did not significantly change peak myocardial opacification (myocardial blood volume) for either technique. Quantification of flow reserve revealed that myocardial blood flow reserve for the dipyridamole group was 3.6 +/- 0.4 (mean +/- 1 standard error of the mean). Real-time MCE is feasible in normal human volunteers and provides homogenous opacification of the myocardium. Furthermore, quantification of myocardial blood flow with real-time MCE in normal human beings produces results that are consistent with the known physiology of the coronary microcirculation.

A trial fibrillation (AF) is a frequent reason for emergency room visits.1 Traditional practice has been to admit patients with new AF for management.2 Despite this widespread practice pattern, the clinical utility of this approach is uncertain, as evidenced by a recent retrospective review of patients with acute, uncomplicated AF.3 A retrospective chart review was performed on all patients presenting with AF to the emergency room at a university hospital from September 1997 to November 1998, to assess the impact of a first episode of uncomplicated AF on clinical outcomes, length of stay, and actual direct costs. • • • Patients meeting the following eligibility criteria had data abstracted: (1) newly diagnosed or new onset AF; (2) uncomplicated clinical status at initial presentation, with no indication for hospital admission other than AF; (3) age between 18 and 75 years; (4) no contraindications to anticoagulation; and (5) no symptomatic congestive heart failure or known left ventricular ejection fraction ,30%. Forty-seven patients were identified. AF was confirmed in each case and the records were abstracted for baseline clinical and demographic information, clinical outcomes, medical management, length of stay, and clinical follow-up after initial presentation. Actual direct costs were calculated using the Transition Systems, Inc., cost allocation system (Eclipsys Corporation, Delray Beach, Florida). The costs of diagnostic testing (echocardiography, stress testing) related to AF after discharge performed on an outpatient basis were included. Subgroup analyses were performed based on the disposition of the patient after emergency room evaluation and on the presence or absence of spontaneous conversion of AF to sinus rhythm. Bivariate comparisons were made using Fisher’s exact test, chi-square test, or Pearson’s chi-square test, and means were compared across groups using Student’s t test. SAS version 6.2 (SAS Institute, Cary, North Carolina) was used for analyses. A p value ,0.05 was considered significant. The study group consisted of 47 patients with a mean age of 57 6 16 years (range 18 to 75). Baseline clinical and demographic characteristics are listed in Table 1. The use of rate control, anticoagulation, and resource utilization after initial presentation are shown in Table 2. The mean length of stay was 1.72 6 0.99 days (range 1 to 5) and the mean actual direct cost was $1,989 6 $1,583 dollars (range $202 to $4,430). The 25th and 75th percentiles for length of stay were 1 and 2 days, and for actual direct costs were $1,171 and $2,443. Among the 47 patients, 39 patients (83%) were admitted to the hospital and 8 patients (17%) were discharged from the emergency room. Mean age and gender ratio did not differ between the admitted paFrom the Cardiovascular Division, Washington University, St. Louis, Missouri; the Heart Care Program, Consortium for Health Outcomes, Innovation, and Cost Effectiveness Studies, and the Department of Emergency Medicine, University of Michigan Health System, Ann Arbor, Michigan. Drs. Kim and Eagle were supported by a research grant from Pharmacia-Upjohn Pharmaceuticals, Kalamazoo, Michigan. Dr. Kim’s address is: Campus Box 8086, Cardiovascular Division,Washington University in St. Louis, 660 S. Euclid Ave., St. Louis, Missouri 63110. E-mail: mkim@im.wustl.edu. Manuscript received September 14, 2000; revised manuscript received and accepted January 24, 2001. TABLE 1 Clinical Features of the Study Group (n 5 47)

ContextAcute aortic dissection is a life-threatening medical emergency associated with high rates of morbidity and mortality. Data are limited regarding the effect of recent imaging and therapeutic advances on patient care and outcomes in this setting.ObjectiveTo assess the presentation, management, and outcomes of acute aortic dissection.DesignCase series with patients enrolled between January 1996 and December 1998. Data were collected at presentation and by physician review of hospital records.SettingThe International Registry of Acute Aortic Dissection, consisting of 12 international referral centers.ParticipantsA total of 464 patients (mean age, 63 years; 65.3% male), 62.3% of whom had type A dissection.Main Outcome MeasuresPresenting history, physical findings, management, and mortality, as assessed by history and physician review of hospital records.ResultsWhile sudden onset of severe sharp pain was the single most common presenting complaint, the clinical presentation was diverse. Classic physical findings such as aortic regurgitation and pulse deficit were noted in only 31.6% and 15.1% of patients, respectively, and initial chest radiograph and electrocardiogram were frequently not helpful (no abnormalities were noted in 12.4% and 31.3% of patients, respectively). Computed tomography was the initial imaging modality used in 61.1%. Overall in-hospital mortality was 27.4%. Mortality of patients with type A dissection managed surgically was 26%; among those not receiving surgery (typically because of advanced age and comorbidity), mortality was 58%. Mortality of patients with type B dissection treated medically was 10.7%. Surgery was performed in 20% of patients with type B dissection; mortality in this group was 31.4%.ConclusionsAcute aortic dissection presents with a wide range of manifestations, and classic findings are often absent. A high clinical index of suspicion is necessary. Despite recent advances, in-hospital mortality rates remain high. Our data support the need for continued improvement in prevention, diagnosis, and management of acute aortic dissection.

A 64-year-old woman with a history of coronary artery bypass graft surgery 2 years earlier presented with a bulging mass on the anterior chest wall 2 weeks after minor chest trauma. She denied having any symptoms, and her examination was remarkable only for a pulsatile mass …

Background The most efficient preoperative assessment for lung volume reduction surgery (LVRS) in patients with advanced emphysema is undefined. This study analyzed the preoperative assessment of patients by surface echocardiography (without and with dobutamine infusion), the results of which were used to exclude patients with significant pre-existing cardiac disease, a contraindication to LVRS, from the surgery. Setting A university-based, tertiary care referral center. Methods Patients with emphysema who met initial LVRS screening criteria underwent resting and stress surface echocardiography with Doppler imaging. Patients were evaluated prospectively for perioperative cardiac complications. Results Between July 1994 and December 1996, 503 candidates for LVRS were evaluated. Of these, 207 patients (81.8%) who had echocardiography performed at our institution formed the primary study group. Images were adequate for the analysis of chamber sizes and function in 206 patients (99.5%) undergoing resting echocardiography, and the images were adequate for wall motion analysis in 172 of 174 patients (98.9%) undergoing functional testing. Right heart abnormalities were common (40.1%). Significant pulmonary hypertension (> 35 mm Hg) was uncommon (5 patients, 5.4%) among the 92 patients who subsequently underwent right heart catheterization. Occult ischemia, left ventricular dysfunction, and valvular abnormalities also were uncommon. Thus, although Doppler imaging estimates of right ventricular systolic pressure were imperfect, echocardiographic findings of normal right heart anatomy and function excluded significant pulmonary hypertension. Ninety patients (43%) eventually underwent LVRS (70 bilateral and 20 unilateral). A total of 13 perioperative cardiac events occurred in 10 patients, 6 of whom had undergone preoperative echocardiography. No patient suffered acute myocardial infarction or cardiac death. Conclusions: Despite potential limitations due to severe obstructive lung disease, surface echocardiographic imaging is a feasible, noninvasive tool in this patient population to identify patients with evidence of cor pulmonale that suggests pulmonary hypertension. The routine use of surface resting and stress echocardiography for preoperative screening obviates the need for invasive right heart catheterization in many patients and results in a low incidence of significant perioperative cardiac complications.

In a randomized, controlled clinical trial, we evaluated the ability of an algorithm to identify, before peak stress, patients who will ultimately require atropine during dobutamine stress echocardiography. The effects of early atropine administration on test duration, atropine dose, dobutamine dose, and heart rate response also were studied. Compared with conventional atropine administration at peak dobutamine infusion, early atropine administration reduced test duration 8% (1.1 minutes, p = 0.02) and total dobutamine use 11% (0.41 mg/kg, p = 0.02) but required 90% more atropine (0.36 mg, p0.001). Conventional atropine administration resulted in a late, rapid rise in both heart rate and rate-pressure product. However, the heart rate and rate-pressure product curves for patients receiving early atropine paralleled those seen in patients not requiring atropine during dobutamine stress echocardiography. In conclusion, early atropine administration provides a more balanced stress and reduces test duration, thus decreasing total exposure to dobutamine and potentially increasing test efficiency.

Dobutamine stress echocardiograms were performed in 6 volunteers under basal conditions and after 72 hours of metoprolol, 50 mg twice daily. Although heart rate responses were blunted, contractility increased to levels seen before beta blockade.