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Biomedical subjects

J Wynne

Publications and source records attributed to J Wynne.

At least 91 records · Page 5Linked to original sources
PubMed1980

Hemodynamic effects of nitrous oxide administered during cardiac catheterization.

To assess the effects of nitrous oxide on hemodynamics and left ventricular function in man, 30 patients (24 of whom had coronary artery disease) were studied at the time of cardiac catheterization. Left ventricular peak-systolic pressure and end-diastolic volume showed no significant change during nitrous oxide inhalation. The maximum rate of pressure rise declined slightly, but left ventricular end-diastolic pressure and ejection fraction were unchanged. Heart rate and cardiac index declined modestly. The pressure-rate product and left ventricular minute work index decreased, suggesting a decline in myocardial oxygen requirements. These data suggest that nitrous oxide inhalation does not produce important depression of left ventricular performance. The consistent decrease in the determinants of myocardial oxygen demand suggests that use of this analgesic agent may be helpful in patients with coronary heart disease.

Adolescent↗
PubMed1980

Oral amrinone in refractory congestive heart failure.

The acute effects of an oral preparation of amrinone, a recently synthesized cardiotonic agent, were assessed noninvasively in nine patients who had advanced heart failure that persisted despite treatment with digitalis, diuretic drugs and afterload-reducing agents. All patients demonstrated an improvement in left ventricular ejection fraction determined by radionuclide ventriculography (20.3 +/- 2.8 to 30.8 +/- 4.8 percent [mean +/- standard error of the mean], p less than 0.005) after a single dose of amrinone. Initial effects were seen within 1 hour, with the peak effect occurring at 1 to 3 hours; persistent effects were demonstrable at 4 to 6 hours. No change in blood pressure, heart rate or rhythm was observed, and there was no clinical evidence of myocardial ischemia. Continued benefit was demonstrated by radionuclide ventriculography in two patients treated for 1 and 6 weeks, respectively, although two other patients experienced major side effects with the chronic administration of amrinone. Although orally administered amrinone shows promise as a potentially useful agent in the treatment of advanced heart failure, the safety of this drug remains to be established.

Aged↗
PubMed1980

Regional left ventricular function in acute myocardial infarction: evaluation with quantitative radionuclide ventriculography.

Regional and global left ventricular performance was noninvasively assessed with quantitative gated equilibrium radionuclide ventriculography in 43 patients an average of 40 hours after the onset of a first acute transmural myocardial infarction. In all 16 patients with anterior infarction, regional ejection fraction, a quantitative measure of regional left ventricular performance, was uniformly depressed in the infarcted zone. In patients with inferior infarction the abnormalities of regional performance were less severe. Fourteen of 20 patients (70 percent) with inferior infarction had depressed performance in the infarcted zone. Function in noninfarcted zones was abnormal in only 6 of the 20 patients (30 percent) with inferior infarction, but it was abnormal in 11 of the 16 patients (69 percent) with anterior infarction, particularly in those with severe pump failure. As a consequence, global left ventricular ejection fraction was significantly lower in patients with anterior than in those with inferior infarction (mean +/- standard error of the mean 31 +/- 3 percent versus 51 +/- 3 percent, less than 0.005). Prognosis and clinical functional class were related to performance not only in infarcted zones, but also in noninfarcted zones as assessed with electrocardiography. It is concluded that depressed function in apparently noninfarcted left ventricular zones contributes significantly to left ventricular dysfunction after acute myocardial infarction, particularly in patients with anterior infarction.

Animals↗
PubMed1980

Multiple-lead QRS changes with exercise testing. Diagnostic value and hemodynamic implications.

To evaluate the diagnostic potential and hemodynamic significance of exercise-induced multiple-lead QRS changes, we studied exercise test responses in 230 patients with chest pain syndromes undergoing Bruce protocol exercise tests. When increases in the R waves of multiple ECG leads (epsilon R) plus ST segment change greater than 1 mm were present, 74 of 75 patients (99%) had coronary disease; this was a higher percentage than that achieved with either measurement alone or when ST change was combined with increase in R in a single lead. Sixty-four of the 75 patients (85%) had multivessel disease, the most severe form of coronary artery disease. Left ventricular end-diastolic pressure (both at rest and after left ventriculography), presence and degree of resting ventricular asynergy, and ejection fraction were all significantly more abnormal in patients whose epsilon R increased, regardless of ST-segment change. Further, in patients who stopped exercise because of cardiac symptoms, exercise duration and the product of heart rate times blood pressure were significantly lower when epsilon R increased. Thus, the mechanism for the increase in epsilon R with exercise in patients with coronary artery disease appears to be related to abnormalities in left ventricular function.

Adult↗
PubMed1980

Disruption in the temporal sequence of regional ventricular contraction. I. Characteristics and incidence in coronary artery disease.

While spatial asynergy at end-systole has been well characterized in patients with coronary artery disease, assessment of regional asynchrony has been hampered by technical constraints. We developed a computer-assisted method for analyzing regional asynchrony from the equilibrium (ECG-gated) radionuclide ventriculogram. Twenty patients with normal contrast left ventriculograms (nine with a normal coronary arteriogram [group 1] and 11 with coronary artery disease [group 2]) and 20 patients with asynergy during contrast ventriculography (group 3) were studied. The earliest evidence of regional asynchrony occurred in early systole. Regional ejection fraction at one-third systole was 0.32 +/- 0.02 (mean +/- SEM) in group 1, 0.22 +/- 0.01 in group 2 (p less than 0.001) and 0.12 +/- 0.01 in asynergic regions in group 3 patients (p less than 0.001). In group 3, severe forms of regional asynchrony appeared in both early systole and early diastole: five patients (25%) had early systolic paradox, 13 (65%) had regional prolongation of peak ejection fraction and 16 (80%) had reduced percent peak ejection fraction at global end-systole. It appears, therefore, that there is progressively increasing regional asynchrony in patients with increasing severity of coronary artery disease.

Coronary Angiography↗
PubMed1980

Infarct avid (hot spot) myocardial scintigraphy.

Infarct avid scintigraphy has emerged as a noninvasive method for determining the presence, location, and extent of myocardial necrosis secondary to infarction. In the future, it may replace studies such as serum enzyme tests, electrocardiography, and vector cardiography, all of which provide only indirect evidence of these parameters.

Animals↗
PubMed1979

Multiple floppy valves: an echocardiographic syndrome.

Echocardiograms of 400 patients with mitral valve prolapse examined at the Peter Bent Brigham Hospital between 1974 and 1977 were reviewed. Eleven patients (3 per cent) were found to have prolapse (10 patients) or large excursion of the tricuspid valve (one patient) and large excursion of the aotric valve (four patients) or dilatation of the aotric root (seven patients) in addition to mitral valve prolapse. Two of these 11 patients underwent mitral valve replacement, and myxomatous degeneration of the valves was noted on pathologic examination. Almost half of the patients with multiple floppy valves (five of 11) had symptoms of congestive heart failure. In contrast to reported series of isolated mitral valve prolapse, in which female preponderance has been documented, 10 of the 11 patients were male. The syndrome of multiple floppy valves may represent either a unique entity or a more advanced form of the same process which underlies mitral valve prolapse.

Adult↗
PubMed1979

Regional ejection fraction: a quantative radionuclide index of regional left ventricular performance.

Radionuclide measurements of regional left ventricular ejection fraction were evaluated as a quantitative index of regional left ventricular function. Left ventricular regional ejection fractions were derived from background-corrected, time-activity curves in 43 patients assessed by both gated equilibrium radionuclide angiocardiography and left ventricular contrast angiography. From a single, modified left anterior oblique projection, the regional change in background corrected counts was determined in each of three anatomic regions. The normal range for regional radionuclide ejection fraction was determined in 10 patients with normal contrast ventriculograms and without obstructive coronary artery disease at coronary arteriography. Regional ejection fraction was compared with percent segmental axis shortening and extent of akinetic segments in corresponding regions of the contrast ventriculogram. Radionuclide and roentgenographic methods were in agreement as to the presence or absence of abnormal wall motion in 83 of 99 left ventricular regions (84%) in 33 patients evaluated prospectively. Comparison of regional ejection fraction demonstrated significant differences between regions with roentgenographically determined normokinesis (75 +/- 3%, mean +/- SEM), hypokinesis (44 +/- 3%, p less than 0.0005) and akinesis (24 +/- 5%, p less than 0.005). We conclude that the left ventricular regional ejection provides a reliable quantitative assessment of regional left ventricular performance.

Adult↗
PubMed1979

Single-photon transaxial emission computed tomography of the heart in normal subjects and in patients with infarction.

Resting computerized transaxial tomography was performed after the i.v. injection of thallium-201 in six normal subjects and in five patients who had had myocardial infarctions 3 mo to 4 yr before scintigraphy. Decreased myocardial activity corresponded to the site of previous infarction in all cases and was clearly separated from adjacent myocardium with normal activity. With tomography, the left ventricle was clearly separated from surrounding structures such as the left-ventricular cavity, the lungs, and the liver. This study demonstrates the feasibility for the assessment of myocardial perfusion using single-photon transaxial emmission computed tomography.

Heart↗
PubMed1979

The paradox image: a noninvasive index of regional left-ventricular dyskinesis.

The paradox image, a functional image of regional dyskinesis derived from the equilibrium (gated) radionuclide ventriculogram, was constructed by subtracting the background-corrected end-diastolic frame from the background-corrected end-systolic frame. In 11 patients showing dyskinesis by contract ventriculography, the percentage of left-ventricular picture elements containing paradox ranged from 3.6 to 55.6% (21.44% +/- 4.45 s.e.m.). In 11 patients with normokinesis and in eight patients with hypokinesis by contract ventriculography, the left-ventricular picture elements demonstrating paradox were less than 1.1% in all cases. In nine patients with akinesis, the percentage of left-ventricular picture elements containing paradox was 2.05% +/- 0.96 s.e.m. and was less tha 2% in seven patients. There was also an excellent agreement between the location of dyskinesis on the paradox image and that by contrast ventriculography. The paradox image is a sensitive indicator of left-ventricular dyskinesis and should be useful in the evaluation of patients with suspected left-ventricular asynergy.

Cardiac Output↗
PubMed1979

Changes in transglutaminase activity in an experimental model of pulmonary fibrosis induced by paraquat.

An experimental model of pulmonary fibrosis has been developed by dosing rats with one-fifth the LD50 dose of the herbicide paraquat on 5 consecutive days. Approximately 50% of the rats died within 4 days of the completion of dosing, showing macroscopic changes and wet weight increases in the lung consistent with severe oedema. Those animals which died between Days 4 and 10 had markedly increased levels of hydroxyproline in the lung, maximum at Day 6, and increased prolyl hydroxylase activity, maximum at Day 4. These changes, together with an increase in thymidine incorporation into DNA, and increased lung DNA content, were consistent with the development of fibrosis. Measurement of transglutaminase activity in the lung showed marked increases at Days 4 and 10 after completion of dosing. This activity paralleled closely the changes in prolyl hydroxylase activity and became increasingly associated with particulate protein present in the "nuclear pellet" fraction. The presence of zymogen plasma transglutaminase trapped in lung homogenates could not be demonstrated but the contribution by the active plasma transglutaminase (Factor XIIIa) to increases shown at Day 4 cannot be ruled out.

Animals↗
PubMed1978

Extrinsic compression of the heart by tumor masquerading as cardiac tamponade.

A patient with known intrathoracic tumor presented with findings suggestive of cardiac tamponade. At cardiac catheterization, the entire heart was displaced superiorly and anteriorly by the tumor mass, and this accounted for the observed cardiac hemodynamics, in the absence of discernible pericardial effusion.

Cardiac Tamponade↗