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Biomedical subjects

J K Oh

Publications and source records attributed to J K Oh.

At least 73 records · Page 4Linked to original sources
PubMed1996

Doppler evaluation of patients with constrictive pericarditis: use of tricuspid regurgitation velocity curves to determine enhanced ventricular interaction.

OBJECTIVES: This study sought to examine the value of analyzing Doppler echocardiographically derived tricuspid regurgitation signals during respiration in relation to the diagnosis of constrictive pericarditis. BACKGROUND: A physiologic hallmark of constrictive pericarditis is enhanced ventricular interdependence, which produces reciprocal changes in right and left ventricular filling and ejection dynamics during the respiratory cycle. It was hypothesized that these changes could be detected noninvasively by analyzing Doppler echocardiographically derived tricuspid regurgitation signals and that this information could assist in noninvasively diagnosing constrictive pericarditis. METHODS: Simultaneous Doppler echocardiography and catheterization studies of the right and left sides of the heart with high fidelity pressure manometers were performed in 5 patients with surgically confirmed constrictive pericarditis and 12 patients (control subjects) with heart failure due to other causes. RESULTS: Changes observed in tricuspid regurgitation Doppler echocardiographic variables from onset to peak inspiration in patients with constrictive pericarditis were significantly different from those in control subjects. Mean (+/- SD) percent change in maximal tricuspid regurgitation velocity was 13% +/- 6% and -8% +/- 7% in the constrictive pericarditis and control groups, respectively (p < 0.0001); mean percent change in tricuspid regurgitation signal duration was 18% +/- 2% and -2% +/- 7%, respectively (p < 0.0001); mean percent change in tricuspid regurgitation time velocity integral was 27% +/- 15% and -10% +/- 12%, respectively (p < 0.0001). CONCLUSIONS: Respiratory changes in Doppler echocardiographically derived tricuspid regurgitation peak velocity and velocity duration are increased in patients with constrictive pericarditis and may be helpful in diagnosing this condition noninvasively.

Aged↗
PubMed1996

Correlation of regional wall motion abnormalities detected by two-dimensional echocardiography with perfusion defect determined by technetium 99m sestamibi imaging in patients treated with reperfusion therapy during acute myocardial infarction.

Twenty patients (13 men and 7 women; mean age 61 +/- 12 years) with > 30 minutes chest pain and new ST-segment elevation who were treated with reperfusion therapy underwent technetium 99m sestamibi imaging and two-dimensional echocardiography simultaneously before and within 2 hours of each test after acute reperfusion therapy. Nine patients had anterior wall myocardial infarction. Fifteen patients were initially treated with intravenous thrombolytic agents, and five patients underwent urgent percutaneous transluminal coronary angioplasty. Both myocardial perfusion defect and wall motion score index (WMSI) improved after reperfusion therapy (perfusion defect from 28% to 15%, WMSI from 1.68 to 1.45, respectively; p < 0.005). The overall correlation between WMSI and perfusion defect as a measure of myocardium at risk was significant during the acute phase (r = 0.71) and at hospital dismissal (r = 0.71). Thus myocardial perfusion defect and wall motion abnormalities correlated fairly well in patients with acute myocardial infarction during the acute phase and at predismissal study.

Adult↗
PubMed1995

Stress echocardiography. Part I. Exercise echocardiography: techniques, implementation, clinical applications, and correlations.

OBJECTIVE: To describe the techniques and applications of exercise echocardiography. DESIGN: We review pertinent experimental and clinical studies from the literature and present our experience with the first 2,000 patients who underwent exercise echocardiography in our laboratory. MATERIAL AND METHODS: The indications for and contraindications to exercise echocardiography and the advantages, limitations, and accuracy of this procedure in comparison with other techniques for detecting coronary artery disease are discussed. RESULTS: Exercise echocardiography is increasingly used for the noninvasive evaluation of coronary artery disease because, in addition to its diagnostic capabilities, it offers attractive features such as portability, versatility, rapid availability of results, and relatively low cost. For accurate interpretation of the results, the workload achieved and the time between completion of exercise and image acquisition must be considered. The major limitation of exercise echocardiography is the high degree of operator dependence. For accurate interpretation of regional wall motion abnormalities and recognition of ischemic changes, specific training and extensive experience are necessary. CONCLUSION: Although exercise echocardiography has only relatively recently become a widely used technique, it has proved to have considerable accuracy in the diagnosis of coronary artery disease (mean sensitivity, 84%; mean specificity, 87%). In high-volume laboratories, feasibility studies have shown success rates between 90 and 99%; thus far, reproducibility has been satisfactory. Other applications of exercise echocardiography being studied are follow-up monitoring after revascularization, determination of prognosis, and assessment of valvular heart disease.

Contraindications↗
PubMed1995

Stress echocardiography. Part II. Dobutamine stress echocardiography: techniques, implementation, clinical applications, and correlations.

OBJECTIVE: To describe the rationale, methods, and clinical applications for dobutamine stress echocardiography. DESIGN: We review our experience with the first 1,000 Mayo Clinic patients who underwent this procedure and discuss studies from the literature that have assessed the accuracy of dobutamine stress echocardiography in determining the presence and extent of coronary artery disease. MATERIAL AND METHODS: The Mayo protocol for dobutamine stress echocardiography is presented, and the indications for use of this test and comparisons of sensitivity and specificity with other tests are summarized. RESULTS: Although exercise stress testing is the usual noninvasive method for the detection and assessment of coronary artery disease, a substantial number of patients are unable to perform adequate exercise because of physical limitations. In these patients, dobutamine stress echocardiography has emerged as a feasible, safe, and accurate method for the evaluation of coronary artery disease. The test has been proved to be valuable in the noninvasive diagnosis of coronary artery disease and to have an accuracy comparable to that of tomographic perfusion imaging. Other indications for dobutamine stress echocardiography include risk stratification before noncardiac surgical procedures, risk stratification after myocardial infarction, and identification of viable myocardium in patients with left ventricular dysfunction. CONCLUSION: Dobutamine stress echocardiography is an accurate, safe, cost-effective, and portable procedure for the noninvasive diagnosis of coronary artery disease and for the preoperative assessment of patients with such disease, especially those who are unable to perform adequate exercise tests.

Adult↗
PubMed1995

Peripheral T-cell lymphoma involving subcutaneous tissue.

The peripheral T-cell lymphomas, presumably derived from various immunocompetent peripheral T-cell system components, form a heterogeneous group of non-Hodgkin's lymphomas. We describe two patients with peripheral T-cell lymphoma primarily involving subcutaneous tissue. They presented with multiple subcutaneous nodules. Skin biopsy specimens in both patients demonstrated a lobular subcutaneous infiltrate. The infiltrate consisted of small and medium-sized atypical lymphoid cells. Both patients had a protracted clinical course before they were diagnosed as having malignant lymphoma. We detected latent Epstein-Barr virus infection in the skin lesions of case 2. Latent Epstein-Barr virus infection might be related to the development of this variant of peripheral T-cell lymphoma.

Adult↗
PubMed1995

Echocardiography in the emergency room: is it feasible, beneficial, and cost-effective?

Echocardiography in the emergency room presents exciting practice possibilities that can facilitate prompt and reliable diagnostic evaluations in patients with suspected cardiovascular emergencies. Echocardiography has the diagnostic potentials to evaluate the entire spectrum of cardiovascular abnormalities short of delineating coronary anatomy and evaluation of the conduction system. By reliably assessing the global and regional function, visualizing the cardiovascular structures from multiple tomographic planes, and quantitating hemodynamic abnormalities, echocardiography should be able to assist emergency room physician's evaluation and triage of the patients with chest pain syndrome, unexplained dyspnea, hypotension, shock, chest trauma, and cardiac arrest, whereby hopefully minimizing the unnecessary admission to the hospital and facilitating inhospital evaluation of the admitted patients with echocardiographic information. However, the optimal echocardiography practice in the emergency room requires well trained sonographers and echocardiographers who can respond to the clinical needs at anytime. Whether an emergency room physician can perform and interpret echocardiographic examinations satisfactorily will depend on his/her level of training and continuing education in this area. Currently, there is no established guideline for performing echocardiography in the emergency room. Further clinical investigations are necessary to define the most optimal and economical utilization of this versatile imaging and hemodynamic diagnostic modality in the emergency room.

Algorithms↗
PubMed1995

Role of transesophageal echocardiography in hemodynamically unstable patients.

OBJECTIVE: To evaluate the clinical impact of transesophageal echocardiography on subsequent management and outcome in hemodynamically unstable patients with suspected cardiovascular pathologic conditions. DESIGN: We reviewed data on patients with hemodynamic instability (hypotension, shock, or pulmonary edema) who underwent transesophageal echocardiography between December 1987 and May 1994. MATERIAL AND METHODS: A total of 127 patients (70 male and 57 female patients with a mean age of 68 years) underwent transesophageal echocardiography at our institution as part of the diagnostic procedures used to evaluate unstable hemodynamics. RESULTS: No clinically significant complication was encountered during the procedure; transesophageal echocardiographic imaging was inadequate in three patients (2%). Of the 124 patients with adequate images, transesophageal echocardiography disclosed a severe cardiovascular abnormality responsible for the unstable hemodynamics in 65 patients (52%), and 26 patients (21%) underwent urgent pericardiocentesis or a cardiac surgical procedure, primarily based on transesophageal echocardiographic findings. CONCLUSION: Transesophageal echocardiography can be safely performed in hemodynamically unstable patients, it produces a high diagnostic yield, and it provides important information for prompt therapeutic decision making. Therefore, we recommend transesophageal echocardiography as one of the initial diagnostic procedures in critically ill patients suspected of having an underlying cardiovascular disorder.

Aged↗
PubMed1995

New index of combined systolic and diastolic myocardial performance: a simple and reproducible measure of cardiac function--a study in normals and dilated cardiomyopathy.

BACKGROUND: Because systolic and diastolic dysfunction frequently coexist, it is hypothesized that a combined measure of left ventricular chamber performance may be more reflective of overall cardiac dysfunction than systolic or diastolic measures alone. METHODS Study patients consisted of 170 subjects: 70 normals, 47 patients with severe dilated cardiomyopathy in NYHA class III-IV awaiting cardiac transplantation and 53 patients with idiopathic dilated cardiomyopathy of intermediate severity [NYHA class II, ejection fractions (EF) 30-50%]. EF, stroke volume and cardiac indexes were measured using conventional echo-Doppler methods. Pre-ejection period/ejection time (PEP/ET), isovolumetric relaxation time (IRT), isovolumetric contraction time/ET (ICT/ET) were also measured. A new derived index of myocardial performance: (ICT+IRT)/ET, was obtained by subtracting ET from the interval between cessation and onset of the mitral inflow velocity to give the sum of ICT and IRT. RESULTS The index was easily measured, reproducible, and had a narrow range in normals. The mean value of the index was significantly different between normal, intermediate and pre-transplant subjects (0.39 +/- 0.05, 0.59 +/- 0.10 and 1.06 +/- 0.24, respectively, p < 0.001 for all comparisons). The degree of inter-group overlap was smaller for the index compared to PEP/ET, ICT/ET and other parameters. Within functional groups, the value of the index did not appear to be related to heart rate, mean arterial pressure and the degree of mitral regurgitation. CONCLUSION (ICT+IRT)/ET is a conceptually new, simple and reproducible Doppler index of combined systolic and diastolic myocardial performance in patients with primary myocardial systolic dysfunction.

Adult↗
PubMed1994

Diagnostic role of Doppler echocardiography in constrictive pericarditis.

OBJECTIVES: This study was conducted to assess the diagnostic role of Doppler echocardiography in constrictive pericarditis. BACKGROUND: It has been observed that patients with constrictive pericarditis have a characteristic Doppler pattern of respiratory variation in ventricular filling and central venous flow velocities. However, the observation was based on a small number of patients with known diagnosis. METHODS: We reviewed the echocardiographic features of 28 patients (21 men and 7 women; mean age +/- SD 55 +/- 15 years) with suspected constrictive pericarditis who underwent exploratory thoracotomy or pericardiectomy. RESULTS: At operation, constrictive pericarditis was diagnosed in 25 patients, restriction in 1 and normal pericardium in 2. Of the 25 patients with constriction, correct preoperative Doppler diagnosis was made in 22 (88%) and Doppler echocardiography showed restriction in 3. In two patients with a normal pericardium, Doppler features were consistent with constriction in one patient and were normal in the other. In the one patient with restriction, Doppler echocardiography showed restriction. In 19 patients with surgically proved constriction, repeat Doppler study after pericardiectomy showed normal findings in 14 and restriction in 5. Twelve of the 14 patients with normalized Doppler findings became asymptomatic, whereas all 5 with restrictive Doppler features remained symptomatic. CONCLUSIONS: Doppler echocardiography performed simultaneously with respiratory recording is highly sensitive for diagnosing constrictive pericarditis, and it appears to predict functional response to pericardiectomy.

Adult↗
PubMed1994

Identification of multivessel coronary artery disease by exercise echocardiography.

OBJECTIVES: This study examined the ability of exercise echocardiography to identify multivessel coronary artery disease and ascertain its incremental value when combined with clinical and exercise test variables. BACKGROUND: Although exercise echocardiography has been shown to be accurate for the detection of coronary artery disease, little is known about its utility for identifying multivessel involvement, and its incremental value when combined with clinical and exercise test variables has not been studied. METHODS: One hundred fifty consecutive patients were selected on the basis of having had an exercise echocardiographic and a coronary angiographic study within 6 months without any revascularization procedure. Significant coronary artery disease (> or = 50% diameter stenosis in any major coronary artery) was present in 117 patients, and multivessel (two- or three-vessel) disease was present in 90 patients. The exercise echocardiographic studies were reviewed by an experienced observer unaware of the results of the coronary angiogram. RESULTS: The overall sensitivity and specificity of exercise echocardiography for the identification of multivessel disease were 73% and 70%, respectively. A stepwise logistic regression analysis identified the number of abnormal regions on the postexercise images as the strongest independent predictor of multivessel disease; also significant were a history of myocardial infarction and ST segment depression of at least 2 mm on the peak exercise electrocardiogram. CONCLUSIONS: Exercise echocardiography adds independent and incremental information to clinical and exercise test variables for identifying multivessel coronary artery disease.

Aged↗
PubMed1993

Evolution of echocardiographic modalities in detection of postmyocardial infarction ventricular septal defect and papillary muscle rupture: study of 62 patients.

Diagnostic sensitivity of various echocardiographic modalities was assessed for postinfarct ventricular septal defect (40 patients) and papillary muscle rupture (22 patients). Two-dimensional transthoracic echocardiography enabled direct visualization of ventricular septal defect in 68% and combined two-dimensional Doppler echocardiography was diagnostic in 95%. Papillary muscle rupture was directly visualized in 45%, and severe mitral regurgitation was present on Doppler color flow images in 100%. Transesophageal echocardiography was diagnostic in all nine patients (five with ventricular septal defect and four with papillary muscle rupture) in whom this modality was applied. Thus two-dimensional Doppler echocardiography (transthoracic and transesophageal if necessary) is highly sensitive in detecting postinfarct ventricular septal defect and papillary muscle rupture.

Aged↗
PubMed1993

Transient constrictive pericarditis: diagnosis by two-dimensional Doppler echocardiography.

Patients with constrictive pericarditis usually require pericardiectomy to relieve their symptoms. In some patients, however, constrictive pericarditis may resolve spontaneously or with medical treatment. Four patients with transient constrictive pericarditis are described in this report. Although the cause of pericarditis differed, all patients had a small to large amount of pericardial effusion, followed by symptoms, signs, and Doppler features typical of constrictive pericarditis. Symptomatic improvement occurred after treatment with some combination of nonsteroidal anti-inflammatory agents, corticosteroids, and antibiotics. The resolution of the symptoms paralleled the normalization of characteristic respiratory changes in Doppler flow velocities. The condition of our patients most likely was related to a transient inflammation (or thickening) of the pericardium due to viral, bacterial, or immunologically mediated pericarditis. Resolution of the thickened pericardium was documented by magnetic resonance imaging in one patient. Awareness of the possible transient nature of constrictive pericarditis in a subgroup of patients with constriction has important clinical implications when pericardiectomy is considered. The resolution of constrictive pericarditis can be documented by serial Doppler echocardiographic examination.

Adult↗
PubMed1993

Multiplane transesophageal echocardiography: image orientation, examination technique, anatomic correlations, and clinical applications.

Multiplane transesophageal echocardiography (TEE) consists of a single ultrasound array or imaging sector that can be rotated around the long axis of the ultrasound beam typically in a 180 degrees arc. This capability produces a circular (conical) continuum of tomographic two-dimensional images. The principal advantage of multiple TEE is that the transducer can be rotated to an image-specific orientation and critically optimized. Thus, manipulation of the transducer is less complex than with the biplane technique, and user adaptation is considerably enhanced. The logical image notation (that is, degrees of rotation) and orientation are described in this report. A step-by-step approach to the multiplane TEE examination, which evolved from our initial experience with 400 consecutive patients, is correlated with accompanying tomographic anatomic corroboration. The unique clinical applications are discussed and related to the amplification of diagnostic information. Although the multiplanar TEE transducer is relatively large, all adult patients who weigh 40 kg or more can be examined. No major complications occurred in our initial experience with this promising new technology.

Adolescent↗
PubMed1993

Echocardiography in valvular heart disease.

Clinical applications of echocardiography continue to grow and be refined with the development of newer technology and the resultant increase in clinical studies. The reliability of echocardiography applied to patients with valvular heart disease has been very well established in determining pressure gradient, stenotic valve area, right-sided cardiac pressure, and ventricular responses (dimension and global systolic function) to pressure and volume overload. Less well established are the determination of regurgitation severity, the role of echocardiography in endocarditis, and the use of the echocardiographic information in clinical decision-making. These issues have been dealt with extensively in the most recent literature. Through superb visualization of the native and prosthetic valvular apparatus by transesophageal echocardiography, new morphologic and functional observations continue to be made.

Echocardiography↗
PubMed1992

Intraoperative evaluation of mitral valve regurgitation and repair by transesophageal echocardiography: incidence and significance of systolic anterior motion.

OBJECTIVE: This study was designed to delineate the utility and results of intraoperative transesophageal echocardiography in the evaluation of patients undergoing mitral valve repair for mitral regurgitation. BACKGROUND: Mitral valve reconstruction offers many advantages over prosthetic valve replacement. Intraoperative assessment of valve competence after repair is vital to the effectiveness of this procedure. METHODS: Intraoperative transesophageal echocardiography was performed in 143 patients undergoing mitral valve repair over a period of 23 months. Before and after repair, the functional morphology of the mitral apparatus was defined by two-dimensional echocardiography; Doppler color flow imaging was used to clarify the mechanism of mitral regurgitation and to semiquantitate its severity. RESULTS: There was significant improvement in the mean mitral regurgitation grade by composite intraoperative transesophageal echocardiography after valve repair (3.6 +/- 0.8 to 0.7 +/- 0.7; p less than 0.00001). Excellent results from initial repair with grade less than or equal to 1 residual mitral regurgitation were observed in 88.1% of patients. Significant residual mitral regurgitation (grade greater than or equal to 3) was identified in 11 patients (7.7%); 5 underwent prosthetic valve replacement, 5 had revision of the initial repair and 1 patient had observation only. Of the 100 patients with a myxomatous mitral valve, the risk of grade greater than or equal to 3 mitral regurgitation after initial repair was 1.7% in patients with isolated posterior leaflet disease compared with 22.5% in patients with anterior or bileaflet disease. Severe systolic anterior motion of the mitral apparatus causing grade 2 to 4 mitral regurgitation was present in 13 patients (9.1%) after cardiopulmonary bypass. In 8 patients (5.6%), systolic anterior motion resolved immediately with correction of hyperdynamic hemodynamic status, resulting in grade less than or equal to 1 residual mitral regurgitation without further operative intervention. Transthoracic echocardiography before hospital discharge demonstrated grade less than or equal to 1 residual mitral regurgitation in 86.4% of 132 patients studied. A significant discrepancy (greater than 1 grade) in residual mitral regurgitation by predischarge transthoracic versus intraoperative transesophageal echocardiography was noted in 17 patients (12.9%). CONCLUSIONS: Transesophageal echocardiography is a valuable adjunct in the intraoperative assessment of mitral valve repair.

Adolescent↗
PubMed1992

Mitral regurgitation due to ruptured chordae tendineae in patients with hypertrophic obstructive cardiomyopathy.

Mitral valve regurgitation in association with hypertrophic obstructive cardiomyopathy is usually caused by the systolic anterior motion of the anterior mitral leaflet. Recently, five patients were encountered with hypertrophic obstructive cardiomyopathy who had mitral regurgitation due to ruptured chordae tendineae. The diagnosis was confirmed in all patients during operation for left ventricular septal myectomy-myotomy (Morrow procedure). Preoperative identification of ruptured chordae tendineae as the cause of mitral regurgitation was established by transesophageal echocardiography in the three most recent cases. All patients had successful septal myectomy-myotomy for relief of left ventricular outflow obstruction, and mitral valve competence was restored by valve repair rather than by prosthetic valve replacement. The clinical course of these patients illustrates important management considerations as well as the utility of transesophageal echocardiography for diagnosis. Chordal rupture should be considered in the differential diagnosis of mitral regurgitation in patients with hypertrophic obstructive cardiomyopathy, especially in those with acute hemodynamic deterioration.

Adult↗
PubMed1992

Mitral valve operation in postinfarction rupture of a papillary muscle: immediate results and long-term follow-up of 22 patients.

The long-term clinical outcome was assessed in 22 patients (15 men and 7 women; mean age, 68 years) who underwent mitral valve replacement or repair for acute mitral regurgitation due to postinfarction rupture of a papillary muscle during the period 1981 through 1990 at the Mayo Clinic. All but three patients underwent operation within the first 3 weeks after acute myocardial infarction. The perioperative mortality was 27%, and the estimated actuarial survival rate at 7 years postoperatively was 47% and 64% for the entire group and for the patients who survived the operation, respectively. The concomitant performance of a coronary artery bypass grafting procedure was the only factor identified that improved both immediate and long-term survival. Patients with a decreased preoperative left ventricular ejection fraction (less than 45%) had somewhat greater short-term and long-term mortality than did those with a left ventricular ejection fraction of 45% or more, but the difference was only of borderline statistical significance. Other factors such as age, sex, severity of coronary artery disease, preoperative existence of congestive heart failure, and timing of the operation in relationship to occurrence of the infarction had no effect on survival. Of the 13 long-term survivors, 10 had significant clinical improvement in comparison with their preoperative state.

Actuarial Analysis↗