Search PubMed⌕ Search

Biomedical subjects

J C Dillon

Publications and source records attributed to J C Dillon.

At least 55 records · Page 3Linked to original sources
PubMed1985

Echocardiographic detection of right atrial thromboembolism.

Deep venous thrombosis may result in the clinical syndrome of pulmonary embolus. In rare instances, embolization has occurred, not directly to the pulmonary arterial tree, but to the right atrium or right ventricle. We report herein two cases of right atrial thromboembolization detected by two-dimensional echocardiography, and we review recently reported similar cases. The echocardiographic appearance of right-sided cardiac thromboembolism may be unique and allow precise noninvasive diagnosis. Mortality was five of five in patients receiving no specific therapy, four of eight in medically treated patients, and one of seven in surgically treated patients. From this review, it appears that there is a high mortality associated with this entity, which may be improved by rapid recognition and institution of specific therapy with anticoagulants, thrombolytic agents, or surgery. In select patients with low surgical risk, prompt exploration and removal of the mass may be indicated.

Adult↗
PubMed1984

Reverse doming of the anterior mitral leaflet with severe aortic regurgitation.

The normal anatomic relation of the anterior mitral leaflet to the left ventricular outflow tract suggests that significant aortic regurgitation should have a predictable hemodynamic effect on the motion and configuration of the leaflet, an effect that should be seen by two-dimensional echocardiography. Previous reports have identified an abnormality of mitral opening in the short-axis view that was quite specific but not sensitive. This study was undertaken to evaluate mitral valve motion and configuration in aortic insufficiency using two-dimensional echocardiography. A characteristic pattern of anterior leaflet motion was found in patients with moderately severe and severe aortic regurgitation. This pattern, termed "reverse doming," was seen in the apical and long-axis views in 19 of 22 such patients. The previously described "diastolic indentation" in the short-axis view was found in 16 of these 22 patients. Only 2 of 16 patients with lesser degrees of insufficiency had reverse doming. The sign was not seen in normal subjects nor in 16 patients with cardiomyopathy. For each of the few false positive and false negative findings, there is a seemingly logical hemodynamic explanation. It is concluded that reverse doming of the anterior mitral leaflet appears to be a sensitive and specific sign for moderately severe and severe aortic regurgitation.

Aortic Valve Insufficiency↗
PubMed1984

Transverse aortic wall tears in infants after balloon angioplasty for aortic valve stenosis: relation of aortic wall damage to diameter of inflated angioplasty balloon and aortic lumen in seven necropsy cases.

Aortic wall tears resulting from rupture of dilating balloons in infants undergoing transluminal balloon angioplasty have not been previously recognized. A 2 day old infant had percutaneous transluminal balloon angioplasty to dilate a stenotic aortic valve, and after multiple balloon inflations the balloon burst. The infant died 2 days after undergoing transluminal balloon angioplasty and at necropsy a circumferential, transverse aortic wall tear was found. To test the hypothesis that rupture of appropriately sized balloons results in similar aortic wall tears, six unfixed, intact infant aortas were subjected to transluminal balloon angioplasty at necropsy: two infants had balloon rupture with inflated balloon diameter similar to that of the aorta, two had balloon rupture with an undersized balloon and two had dilation with an oversized balloon. Transverse wall tears occurred in aortas with similar aortic and balloon diameters; no aortic wall damage occurred with rupture of undersized balloons, and aortic rupture resulted from the use of oversized balloons. Thus, intimal-medial tears in the infant aorta may result from balloon bursting during angioplasty when aortic and inflated balloon diameters are similar.

Angioplasty, Balloon↗
PubMed1984

Assessment of location and size of myocardial infarction with contrast-enhanced echocardiography. II. Application of digital imaging techniques.

Contrast echocardiography can be used to identify nonperfused regions of myocardium and localize and quantify infarcted myocardium. Analysis is usually undertaken by visual inspection of an analog two-dimensional echocardiographic image. The purpose of our study was to apply digital imaging techniques to contrast-enhanced echocardiograms for the determination of myocardial infarct size. Myocardial contrast was produced by an injection into the aortic root of a mixture of hydrogen peroxide and blood. Sixteen open chest dogs were studied 4 hours after coronary artery occlusion. Echocardiograms were evaluated by two independent observers. The results were compared with infarct location and size determined with nitro-blue tetrazolium staining of the corresponding slice of the left ventricle. Both the routine analog echocardiographic image and the digital subtraction image were analyzed. For the latter, three precontrast and three postcontrast echocardiographic enddiastolic fields were digitized in a 256 X 256 X 6 bit matrix and then averaged. Average pre- and postcontrast images were mathematically subtracted to form the digital subtraction image. There was excellent correlation between the percent of infarct determined with digital subtraction contrast echocardiography and results of nitro-blue tetrazolium staining (r = 0.97, SEE = 0.04, p less than 0.001). Using linear regression, the relation between infarct size by the two studies was best described by the equation DSI = 0.92 NBT + 0.03, where DSI = digital subtraction image and NBT = infarct size by nitro-blue tetrazolium. Inter- and intraobserver variability were also excellent (r = 0.93 and 0.96, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Diastolic ventricular septal motion in atrial septal defect: analysis of M-mode echocardiograms in 31 patients.

Previous echocardiographic studies suggest that diastolic motion of the ventricular septum reflects relative filling of the right and left ventricles. We studied 31 patients with atrial septal defect by M-mode echocardiography. Early diastolic posterior ventricular septal motion (DPSM) occurred in all patients. Measurement of DPSM correlated with pulmonary to systemic flow ratios (Qp:Qs) (r = 0.64, p less than 0.001). All 15 patients with DPSM greater than 5 mm had a Qp:Qs greater than 2.5:1, whereas only 8 of 16 patients with DPSM less than 5 mm had a shunt this large (p less than 0.003). DPSM greater than 5 mm in patients with atrial septal defect is a specific but not sensitive echocardiographic sign of a large left-to-right shunt. Our findings substantiate the hypothesis that diastolic motion of the ventricular septum reflects relative filling of the ventricles.

Adolescent↗
PubMed1983

Exercise echocardiography: a clinically practical addition in the evaluation of coronary artery disease.

There has been only modest clinical interest in exercise echocardiography because of the technical limitations of the procedure. Recognizing that there have been recent technical advances in the echocardiographic instruments and that echocardiography should, in theory, be an ideal technique for evaluating exercise-induced wall motion abnormalities, a clinically practical method of performing exercise echocardiograms was developed. By obtaining the echocardiograms immediately after treadmill exercise, with the patient sitting at the treadmill, a high percent of studies adequate for interpretation was obtained (92%). The addition of echocardiography to the treadmill exercise test significantly enhanced the diagnostic yield. In addition, in cases of one and three vessel disease, exercise echocardiography identified stenosis in specific coronary arteries. In patients with two vessel disease and left circumflex obstruction, specific vessel identification was less reliable. A high percent of patients with multivessel disease developed wall motion abnormalities with exercise that persisted for at least 30 minutes. It is concluded that echocardiography performed immediately after exercise with the new generation of echocardiographs can be a practical and useful clinical tool.

Adult↗
PubMed1983

[Clinical and biochemical aspects of riboflavin deficiency in Haiti].

A study has been carried out in Haiti, involving 65 human subjects, mostly children, 39 of which had clinical symptoms of riboflavin deficiency, in order to correlate clinical symptoms and erythrocyte glutathion reductase activity. Angular stomatitis was associated with overt biochemical deficiency in 25% of the cases examined and in most cases seemed to be related to other nutritional or infectious disorders.

Adolescent↗
PubMed1982

Echocardiographic detection of left main coronary artery obstruction.

Advances in two-dimensional echocardiography have improved the prospects of using this technique to detect left main coronary artery (LMCA) obstruction. Using an echocardiograph that had digital gray scale, a 3-MHz transducer and strobe freeze-frame capability and reviewing recordings on an off-line videotape-videodisc analyzer, we retrospectively examined the LMCA in 72 patients who underwent coronary cineangiography. Angiography showed 50% or greater LMCA obstruction in seven patients. All seven had high-intensity echoes in the walls of the LMCA. The high-intensity echoes were irregularly located in the artery and partially occluded it. The LMCA could frequently be recorded proximal and distal to the obstruction. A blinded observer reviewed 28 randomly selected patients from this group and correctly identified the four patients with LMCA obstruction. There was one true and two questionable false-positive diagnoses. In a prospective study of 31 patients, two independent observers correctly identified the three patients with LMCA obstruction. There were no false negatives, and one observer had one false positive. All of the false positives were in patients with proximal left anterior descending coronary artery obstructions. Echocardiography may be a practical means of identifying patients with the LMCA obstruction.

Coronary Angiography↗
PubMed1982

Diastolic collapse of the right ventricle with cardiac tamponade: an echocardiographic study.

The value of a newly described echocardiographic sign for the detection of cardiac tamponade was retrospectively evaluated in 91 patients. M-mode echocardiograms were reviewed in 86 patients, 36 of whom had concurrent two-dimensional echocardiographic examinations; in five patients, only two-dimensional echocardiography was performed. Cardiac tamponade was clinically present in 17 patients, 14 of whom had abnormal posterior motion of the right ventricular free wall in early diastole. Two of the 17 patients with tamponade had equivocally abnormal motion and one had normal wall motion. The patient with normal wall motion was later proved to have predominantly constrictive pericardial disease. In all cases, the abnormal wall motion reverted to normal after a definitive drainage procedure. Two-dimensional echocardiography confirmed that the abnormal right ventricular wall motion represented a true collapse of the right ventricular cavity in early diastole. Of the 69 patients without clinical cardiac tamponade, only seven had abnormal right ventricular wall motion. Detection of abnormal diastolic right ventricular free wall motion may be a sensitive indicator or a hemodynamically significant pericardial effusion. Conversely, the presence of normal motion of the right ventricular free wall appears to be a reliable indicator that the pericardial effusion is exerting little effect on overall cardiac function.

Cardiac Tamponade↗
PubMed1981

Reliability of two-dimensional echocardiography in assessing the severity of valvular aortic stenosis.

Two-dimensional echocardiographic studies have shown that maximum long-axis systolic aortic cusp separation (MACS) represents a useful, noninvasive method for estimating severity of valvular aortic stenosis in adults. Although mean values for patients with mild, moderate, and severe aortic stenosis have been clearly separated by this method, overlap occurs among individual patients. In this study, 81 adults with aortic stenosis were studied by two-dimensional echocardiography in the long-axis view. Long-axis assessment of aortic stenosis was obtainable in 93 percent of the patients. Less than 8-mm separation was 97 percent predictive of severe stenosis and 100 percent predictive of moderate or severe stenosis. Eight- to 12-mm had a low predictive value for the severity of stenosis. Greater than 12-mm separation was 96 percent predictive of mild aortic stenosis. Short-axis scans were attempted in 61 of the 81 subjects. Short axis assessment of aortic stenosis based on patterns of leaflet motion was obtainable in 46 of the 61 patients (73 percent) and provided a valuable index of severity. When short-axis scans were included in the assessment of severity in the subgroup of patients with 8- to 12-mm MACS, the predictive value improved greatly (86 percent vs 46 percent). Direct recording of aortic valve area in short-axis was successful in only 13 percent of the subjects. The echo aortic valve area compared with the hemodynamic calculated aortic valve area yielded an r = 0.87.

Adult↗