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Biomedical subjects

J K Oh

Publications and source records attributed to J K Oh.

At least 109 records · Page 6Linked to original sources
PubMed1988

Prediction of the severity of aortic stenosis by Doppler aortic valve area determination: prospective Doppler-catheterization correlation in 100 patients.

Two-dimensional and Doppler echocardiography was performed prospectively in 100 patients with aortic stenosis who were undergoing clinically indicated cardiac catheterization. The purpose of this study procedure was to determine various Doppler variables predictive of the severity of aortic stenosis and to compare Doppler- and catheterization-derived aortic valve areas. Doppler-derived mean gradient correlated well with corresponding gradient by catheterization (r = 0.86). Peak Doppler aortic flow velocity greater than or equal to 4.5 m/s and Doppler-derived mean aortic gradient greater than or equal to 50 mm Hg were specific (93 and 94%, respectively) for severe aortic stenosis (defined as catheterization-derived aortic valve area less than or equal to 0.75 cm2) but were not sensitive (44 and 48%, respectively). Doppler-derived aortic valve area calculated by the continuity equation correlated well with catheterization-derived aortic valve area calculated by the Gorlin equation when either the time-velocity integral ratio (r = 0.83) or the peak flow velocity ratio (r = 0.80) between the left ventricular outflow tract and the aortic valve was used in the continuity equation. A velocity ratio of less than or equal to 0.25 alone was sensitive (92%) in detecting severe aortic stenosis. Therefore, use of various Doppler-derived values allows reliable noninvasive estimation of the severity of aortic stenosis.

Aged↗
PubMed1988

Successful treatment of pulmonary embolism and associated mobile right atrial thrombus with use of a central thrombolytic infusion.

Patients with pulmonary embolism and two-dimensional echocardiographic evidence of right atrial thrombus have a high mortality rate despite standard anticoagulation therapy. We used a direct central infusion of streptokinase in three such patients, who subsequently had rapid and complete clinical improvement. In this setting, thrombolytic therapy should be considered an effective therapeutic option.

Adult↗
PubMed1988

Transesophageal echocardiography: technique, anatomic correlations, implementation, and clinical applications.

The introduction of transesophageal echocardiography has provided a new acoustic window to the heart and mediastinum. High-quality images of certain cardiovascular structures [left atrial appendage, thoracic aorta, mitral valvular apparatus, and atrial septum] can be obtained readily (average examination, 15 to 20 minutes). In this article, we discuss the technique of image acquisition, image orientation, and anatomic validation. In addition, we describe our experience with the first 100 awake patients who underwent transesophageal echocardiography at our institution. The procedure was well accepted by the patients and associated with no major complications. The clinical indications for this procedure have included thoracic aortic dissection, prosthetic cardiac valve dysfunction, detection of an intracardiac source of embolism, endocarditis, cardiac and paracardiac masses, and mitral regurgitation. Transesophageal echocardiography also proved to be useful in assessment of critically ill patients in whom standard transthoracic echocardiographic images did not provide complete assessment. In these patients (who had extensive chest trauma, had undergone an operation, or were in an intensive-care unit), rapid assessment of the cardiovascular status at the bedside was possible with transesophageal echocardiography. On the basis of our initial experience, we conclude that transesophageal echocardiography complements standard two-dimensional Doppler and color flow examinations and will considerably improve the care of patients with cardiovascular disorders by providing high-quality unique images.

Aorta, Thoracic↗
PubMed1988

Significance of T-wave pseudonormalization during exercise. A radionuclide angiographic study.

In 84 consecutive patients with resting T-wave inversion, radionuclide angiography revealed significant new wall motion abnormalities in 13 (28 percent) of the 47 patients with persistent T-wave inversion and in 23 (62 percent) of the 37 patients with T-wave pseudonormalization during exercise (p less than 0.01). The response of the ejection fraction to exercise was better in patients with persistent T-wave inversion than in those with pseudonormalization (p less than 0.04). Mechanical evidence of ischemia was seen in 14 (61 percent) of the 23 patients with T-wave pseudonormalization but without ST-segment depression. In patients with resting T-wave inversion, pseudonormalization was slightly more sensitive but less specific than a positive exercise test for predicting significant new wall motion abnormalities or decreases in the ejection fraction with exercise. Although pseudonormalization is not extremely useful alone, the presence or absence of this finding can increase the diagnostic accuracy of exercise electrocardiography in patients with resting T-wave inversion and suspected ischemic heart disease.

Coronary Disease↗
PubMed1987

Evaluation of acute chest pain syndromes by two-dimensional echocardiography: its potential application in the selection of patients for acute reperfusion therapy.

Two-dimensional echocardiography is useful for the immediate diagnosis of acute myocardial infarction when diagnostic electrocardiographic changes are absent. The technique is also helpful in distinguishing myocardial infarction from other conditions that may clinically or electrocardiographically mimic infarction. The extent of myocardial infarction can be estimated by the two-dimensional echocardiographically derived wall motion score index. Therefore, two-dimensional echocardiography seems to be ideally suited for the initial noninvasive assessment of patients with acute chest pain syndromes, especially those who are considered for acute reperfusion therapy.

Adult↗
PubMed1985

Creatine kinase release after successful percutaneous transluminal coronary angioplasty.

After successful percutaneous transluminal coronary angioplasty (PTCA), 25 (20%) of 128 patients had elevation of creatine kinase MB isoenzyme (CK-MB). The increase was mild (mean 9% MB with total creatine kinase of 179 U/L). Three variables were significantly related to the enzyme elevation: chest pain, small branch vessel occlusion, and recent myocardial infarction. Of the patients with CK-MB elevation, 60% experienced chest pain and 32% sustained a small branch vessel occlusion during PTCA, compared with 11% and 8%, respectively, of the 103 patients without enzyme elevation (p less than 0.001 and p less than 0.01). Of 16 patients with recent myocardial infarction, seven (44%) had release of CK-MB. Although mild enzyme elevation after successful PTCA is likely due to a small amount of myocardial necrosis, this phenomenon was not associated with increased cardiac morbidity or mortality. Therefore, release of CK-MB without other clinical evidence for myocardial infarction after successful PTCA does not in itself warrant longer hospitalization, and routine serial enzyme determinations are probably unnecessary. By reducing the number of laboratory tests and the duration of hospitalization, the cost effectiveness of PTCA may be increased.

Angiocardiography↗
PubMed1985

Cardiac arrhythmias in patients with surgical repair of Ebstein's anomaly.

Preoperative, perioperative and postoperative arrhythmias in 52 consecutive patients who underwent operation for Ebstein's anomaly were reviewed. There were 25 male and 27 female patients (mean age 18 years, range 11 months to 64 years). Thirty-four patients had one or more documented arrhythmias preoperatively (18 had paroxysmal supraventricular tachycardia, 10 had paroxysmal atrial fibrillation or flutter, 13 had ventricular arrhythmia and 3 had high grade atrioventricular block). Seven patients without documented arrhythmias had a history typical of tachyarrhythmias. During the perioperative and early postoperative periods, 14 patients had atrial tachyarrhythmias and 8 had ventricular tachycardia or ventricular fibrillation. There were seven deaths between day 1 and 27 months after operation. Five of these deaths were sudden (all in male patients, aged 12 to 34 years), and four of the patients had had perioperative ventricular tachycardia or ventricular fibrillation. One patient was taking one antiarrhythmic agent and another patient was taking two at the time of sudden death. Of the 18 patients with paroxysmal supraventricular tachycardia and 9 patients with paroxysmal atrial fibrillation or flutter preoperatively who were followed up for a mean of 40 and 36 months, respectively, 22 and 33% continued to have symptomatic tachycardia. Of the 11 patients (mean age 9 years) without preoperative documentation or symptoms of arrhythmia, follow-up data were obtained (range 1 to 144 months, mean 31) in 9 patients. None died suddenly or developed symptomatic arrhythmia.

Adolescent↗
PubMedDate not supplied

Restrictive left ventricular diastolic filling identifies patients with heart failure after acute myocardial infarction.

Left ventricular diastolic filling was characterized by transmitral pulsed-wave Doppler velocities in 62 patients with acute myocardial infarction, and diastolic filling variables were correlated with the presence of clinical heart failure. At the time of admission, 47 patients were free of heart failure and 15 patients were in Killip class II to IV. In the latter group of patients with heart failure, peak velocity of late filling wave caused by atrial contraction (A) was lower (0.48 versus 0.59 m/sec, p < 0.05), ratio of peak velocity of early rapid filling wave to peak velocity of late filling wave caused by atrial contraction (E/A) was higher (1.5 versus 1.1, p < 0.01), and deceleration time (136 versus 196 msec, p = 0.0001) was shorter when compared with the patients not in heart failure after acute myocardial infarction. Multivariate analysis showed that the deceleration time was a powerful independent predictor of presence of heart failure after controlling for systolic functional variables. Therefore, diastolic filling variables can complement systolic functional variables in the identification of the patients with postinfarction left ventricular failure.

Adult↗
PubMedDate not supplied

Critical appraisal of transesophageal echocardiography: limitations, pitfalls, and complications.

Because transesophageal echocardiography is invasive, it has the potential for serious complications. Limitations occur because of the restricted transducer mobility within transducers for special situations. Pitfalls (potential erroneous diagnoses resulting from misinterpretation of normal and abnormal anatomy) are prevalent with this new technology. This report critically reviews transesophageal echocardiography and discusses and illustrates commonly encountered limitations, pitfalls, and complications.

Echocardiography↗
PubMedDate not supplied

Effect of sample volume location on Doppler-derived transmitral inflow velocity values.

In 25 patients with acute myocardial infarction and in 25 normal subjects, pulsed-wave Doppler echocardiography was performed in the apical four-chamber view with the sample volume first between the mitral leaflet tips and then at the mitral anulus. The early filing wave (E) and late filling wave (A) peak velocities measured from Doppler strip charts were significantly (p less than 0.001) higher at the tips in both groups. E velocity increase was greater than A velocity increase, producing a significantly (p less than 0.001) higher E/A velocity ratio at the tips than at the anulus. The deceleration time was longer at the tips than at the anulus (p less than 0.001) in both groups. Therefore it is important to know sample volume location in the interpretation of mitral inflow velocity. It is critical to maintain the same sample volume location in serial assessments of left ventricular diastolic filling characteristics.

Adult↗
PubMedDate not supplied

Traumatic left ventricular false aneurysm with significant regurgitation from left ventricular outflow tract to left atrium: delineation by two-dimensional and color flow Doppler echocardiography.

A 22-year-old man was asymptomatic 23 months after an automobile accident but had clinical evidence of progressive mitral insufficiency. Two-dimensional and color flow Doppler echocardiography demonstrated a false aneurysm adjacent to the left ventricular outflow tract and significant regurgitation of blood through a traumatic channel from the left ventricular outflow tract to the left atrium. The patient underwent successful surgical closure of the false aneurysm and repair of the traumatic left atrial regurgitation.

Adult↗
PubMedDate not supplied

Visualization of sinus venosus atrial septal defect by transesophageal echocardiography.

Atrial septal defect (ASD) is usually suspected clinically but requires a confirmative diagnostic procedure before surgical repair. Two-dimensional and Doppler echocardiography have high sensitivity and specificity for ASD, but the sensitivity of echocardiography is not as high in detecting sinus venosus ASD as it is in ostium primum or secundum defect because of the difficulty in visualizing the sinus venosus area from the subcostal window. For the posteriorly located cardiac structures, including the atrial septum, visualization is superior by transesophageal echocardiography. We describe a case in which sinus venosus ASD was not visualized by conventional transthoracic echocardiography but was diagnosed confidently by transesophageal echocardiography.

Echocardiography↗
PubMedDate not supplied

Two-dimensional and Doppler echocardiographic assessment of infiltrative cardiomyopathy.

Infiltrative cardiomyopathies can be divided by disease into infiltrative and storage disorders that show an increase in ventricular wall thickness caused by infiltration of pathologic substances between cells, as with amyloid and sarcoid, or deposition within cells, as with iron, glycogen, and lipid. Two-dimensional and Doppler echocardiography are powerful noninvasive tools in the assessment of the anatomic and functional characteristics of these disorders. With cardiac amyloidosis as the prototype, the constellation of findings of a small or normal left ventricular cavity size; markedly increased thickness of the ventricular walls, associated with a highly abnormal texture; and biatrial enlargement make up its characteristic appearance. However, there is a wide spectrum of abnormalities in this disorder, depending on the stage and duration of heart involvement. Doppler assessment of diastolic function is frequently abnormal in cardiac amyloidosis. Cardiac sarcoidosis usually is evident by a dilated segmental cardiomyopathy with regional wall abnormalities. Similarly, hemochromatosis appears as a dilated cardiomyopathy with normal wall thickness. The echocardiographic appearance of glycogen and glycolipid storage diseases is similar to cardiac amyloidosis, and biochemical analysis may be necessary for differentiation. Thus echocardiography is an important tool in the characterization of infiltrative cardiomyopathies.

Amyloidosis↗
PubMedDate not supplied

Aortic dissection: review of value and limitations of two-dimensional echocardiography in a six-year experience.

The utility of transthoracic two-dimensional echocardiography in patients with aortic dissection was assessed by retrospective analysis in 67 patients: 31 patients with DeBakey type I, 21 patients with type II, 10 patients with type III, and five patients with false-positive diagnoses. Aortic dissection was correctly identified by two-dimensional echocardiography in 49 patients; 13 had false-negative diagnoses. Therefore the sensitivity was 79%, and the positive predictive accuracy was 91%. Transthoracic two-dimensional echocardiography is a reasonable screening technique for diagnosis of aortic dissection.

Acute Disease↗
PubMedDate not supplied

Frequency of Doppler measurable pulmonary artery pressures.

The current literature suggests that right-sided heart pressures can be obtained noninvasively in approximately 60% of patients. We hypothesized that with a focused echocardiographic Doppler examination, measurable tricuspid or pulmonary valve regurgitation suitable for measuring pressures could be obtained in a higher percentage of patients. The study group consisted of 200 consecutive patients undergoing echocardiographic and Doppler hemodynamic evaluation. All patients were first examined by an ultrasonographer instructed to attempt to record tricuspid and pulmonary regurgitant velocities. After this examination, a designated cardiologist performed a focused examination with the intent of improving the signal quality and increasing the number of measurable signals for evaluation. Tricuspid regurgitation of measurable quality was recorded in 147 (73.5%) of 200 patients by the ultrasonographer; this result was improved to 172 patients (86%) by the designated cardiologist. Pulmonary regurgitation was obtainable in 147 (95%) of 154 patients and was of measurable quality in 137 (89%). When results of tricuspid and pulmonary regurgitation were combined, a quantifiable signal was obtained in 194 (97%) of 200 consecutive unselected patients. This study demonstrates that a well-trained ultrasonographer or echocardiologist can obtain right-sided pressures in at least 95% of all unselected cardiovascular patients.

Adolescent↗