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Biomedical subjects

A Battler

Publications and source records attributed to A Battler.

At least 145 records · Page 8Linked to original sources
PubMed1980

Improvement in ventricular function during exercise studied with radionuclide ventriculography after cardiac rehabilitation.

A heterogeneous group of 19 consecutive patients with coronary artery disease were studied with radionuclide ventriculography before and after a mean of 6 months of exercise training. Ejection fraction was measured at rest, at matched submaximal supine work loads and during maximal supine bicycle exercise. After training there was no change in mean ejection fraction at rest or during maximal exercise, but a higher maximal mean systolic blood pressure, heart rate and work load were achieved. At equivalent submaximal work loads after training, similar levels of mean heart rate and systolic blood pressure were reached but a statistically greater mean ejection fraction was obtained. These preliminary results suggest that exercise training may improve cardiac function during exercise in selected patients with coronary disease. A randomized study using similar techniques has been initiated.

Adult↗
PubMed1980

Detection of latent coronary stenosis in conscious dogs: regional functional and electrocardiographic responses to isoprenaline.

A conscious animal model was developed in which coronary stenosis could be produced while regional myocardial function and local surface electrocardiograms were measured. Responses to isoprenaline stress in the presence of mild (latent) coronary stenosis were then examined. In the absence of coronary stenosis, isoprenaline produced increases in regional function and no change in the surface VCG; at higher doses, increases in the endocardial ST segments occurred. After partial coronary stenosis, which produced no apparent regional dysfunction or electrocardiographic changes, isoprenaline infusion for 3 min (0.02 microgram . kg-1 . min-1) rapidly produced decreases in percentage wall thickening (average 17 +/- 4%, mean +/- SE, P < 0.01) and increases in the mean sum of VCG ST segments by 0.23 +/- 0.06 mV (P < 0.05). 1 min after stopping isoprenaline, most dogs showed further significant deterioration of both measures of ischaemia, but by 5 min there was no significant mean change from control. We conclude that in the presence of latent partial coronary stenosis, stress due to mild sympathomimetic stimulation alone can rapidly induce regional myocardial ischaemia. Deterioration of regional myocardial contractile function during such stress can provide as sensitive means of detecting latent coronary obstruction.

Animals↗
PubMed1980

Influence of different background and left-ventricular assignments on the ejection fraction in equilibrium radionuclide angiography.

Seventy-six patients were studied within one week of contrast ventriculography to assess the influence of differing background assignments on ejection fractions derived from gated equilibrium radionuclide anigograms. "Fixed" and "variable" left-ventricular regions on interest and five different backgrounds were used. Inter- and intra-observer variability were determined, and 15 patients underwent a second study 2 weeks later. Variable left-ventricular regions of interest produced higher ejection fractions than fixed ones. A computer-assigned background or a ring drawn manually around the left ventricle correlated best with contrast ventriculography, giving greater serial and inter- and intra-observer variability. Automated background assignments reduced variability and increased reproducibility, though not always associated with the best correlation with contrast ventriculography. Thus a variety of left-ventricular and background regions of interest gives excellent reproducibility and accuracy.

Adult↗
PubMed1980

First-third ejection fraction at rest compared with exercise radionuclide angiography in assessing patients with coronary artery disease.

To compare two methods of evaluating patients with coronary artery disease, the authors assessed the ejection fraction (EF) during the first-third (1/3) of systole by first-pass radionuclide angiography and the EF response to exercise in 22 normal individuals and 40 patients. The 1/3 EF was calculated by averaging 3--5 beats on the time--activity curve. Exercise EFs were obtained by gated cardiac imaging. The results are shown below, including the per cent change in EF with exercise (% EF). (Formula: see text) p less than 0.05 vs. normals; p less than 0.001 vs. normals; all results are +/- SD. Thirty per cent of patients had a depressed EF, 98% had a depressed 1/3 EF, and 88% had an abnormal EF response to exercise. It is concluded that the 1/3 EF by first-pass radionuclide angiography at rest may be at least as sensitive in identifying patients with coronary artery disease as the EF response to exercise.

Adult↗
PubMed1980

Physical activity and coronary heart disease.

This review deals with more recent investigations of the health benefit of regular aerobic exercise including studies in: epidemiology, echocardiography, animal research, and cardiac rehabilitation. Recent epidemiological studies support the preventative aspects of exercise in apparently healthy individuals. Echocardiographic studies suggest morphologic changes in young individuals. Recent animal research confirms previous results as well as documenting improvment in cardiac function even under hypoxic and ischemic conditions. Studies of cardiac rehabilitation suggest that medically supervised programs do not improve or worsen morbidity and mortality. The question of whether exercise training can cause cardiac effects in patients with coronary disease rather than just improve the response of the peripheral circulation to exercise may be answered using newer radionuclide techniques.

Adult↗
PubMed1980

Comparison of rest/exercise ECG, thallium-201 scans and radionuclide angiography in patients with suspected coronary artery disease.

The results of rest and exercise ECG, 201Tl myocardial perfusion imaging and equilibrium radionuclide angiography were analyzed in 71 consecutive patients referred for diagnosis or evaluation of coronary artery disease (CAD). In 45 patients the diagnosis was established either by catheterization or typical history. In this group the overall sensitivity for rest/exercise ECG was 66%, for 201Tl scans 74%, for both combined 79% and for the ejection fraction response to exercise determined by radionuclide angiography 97%. If only the exercise response was considered, the corresponding sensitivity values were 58% (ECG), 50% (201Tl scans), 71% (ECG + 201Tl) and 97% (radionuclide angiography). The specificity for coronary artery disease was determined to be 71% for ECG, 86% for 201Tl scans and 42% for radionuclide angiography. All patients with false-positive results by radionuclide angiography had cardiomyopathies, thus this test has a high specificity for left ventricular dysfunction rather than for CAD alone. Criteria developed from the analysis of the test results in the 45 patients with definite diagnoses were then applied to the evaluation of 26 additional patients with atypical chest pain. A diagnosis could be made in all but 5 of them and radionuclide angiography was again the single most reliable test. Based on this study a new approach for the noninvasive evaluation of patients with suspected coronary artery disease is proposed.

Angiography↗
PubMed1980

Effect of reserpine upon the haemodynamic course of recovery following experimental myocardial infarction.

Acute haemodynamic consequences of coronary artery ligation were evaluated in twenty-four anaesthetized open-chest dogs, nine of which were pretreated with reserpine. The following parameters were measured before, and at 15-min intervals following ligation for at least five hours : ECG, mean arterial blood pressure, aortic blood flow, left ventricular pressure, heart rate, peripheral resistance (P.R.), end-diastolic pressure, dP/dtmax, and "internal work" (I.W. = heart rate x dP/dtmax). It was found that aortic flow was similar in control and reserpine-pretreated dogs (753 +/- 43 vs. 744 +/- 57 ml/min respectively), even though heart rate, blood pressure and other parameters were significantly higher in the control animals. Furthermore, the controls could be divided into two groups : recoverers (R) and non-recoverers (N), on the basis of late stage haemodynamic differences. The ratio of PR/IW taken within one hour of ligation was significantly higher in the R group (496 +/- 69) and reserpine group (479 +/- 30) than in the N group (242 +/- 28), and could predict course of recovery in each dog studied. It is concluded that the presence of myocardial catecholamines may be deleterious to the ischemic heart when the PR or IW are disproportionately altered.

Animals↗
PubMed1980

Cardiac rehabilitation: evidence for improvement in myocardial perfusion and function.

Sixteen patients with coronary heart disease (CHD) were studied with rest and exercise thallium scans and gated radionuclide ventriculography before and after 3 to 12 months of exercise training. The 5 patients presented in this report showed improvement in both the ejection fraction and exercise thallium images after training while achieving a higher maximal workload and an equivalent double product. These radionuclide techniques have provided the 1st documentation of improvement in both myocardial perfusion and function in CHD patients after exercise training. A controlled study using advances in imaging technology with patients matched according to postmyocardial infarction time and by the severity of disease is underway to confirm these findings.

Adult↗
PubMed1980

Differential diagnosis of atypical chest pain syndromes by equilibrium radionuclide angiography during exercise.

In order to describe exercise-induced changes of left ventricular function in patients with atypical chest pain and to determine the diagnosis accuracy of radionuclide angiography in the differential diagnosis of various chest pain syndromes, we studied a consecutive series of 26 patients and 20 healthy volunteers. Only patients with ejection fractions > 0.50 at rest, without antianginal therapy and without a prior myocardial infarction who eventually underwent diagnostic left heart catheterization were included in the study. In all healthy volunteers ejection fraction increased during exercise by at least 10% over the resting level (from 0.61 +/- 0.05 to 0.76 +/- 0.07; P < 0.001). A similar ejection fraction response was found in 14 of the 26 patients (group A): ejection fraction increased from 0.60 +/- 0.06 to 0.72 +/- 0.07 (P < 0.001), whereas in the remaining 12 patients (group B) ejection fraction decreased from 0.62 +/- 0.06 to 0.57 +/- 0.07 (P < 0.01). Left heart catheterization revealed normal coronary arteries in 13/14 group-A patients while 10/12 group-B patients had significant coronary artery lesions (> 50%). The other two group-B patients were found to have idiopathic cardiomyopathies. We conclude that normal subjects with atypical chest pain during exercise have a normal ejection fraction response to exercise despite their symptoms and that therefore radionuclide angiography during exercise is a valuable noninvasive method in the differential diagnosis of exercise-induced chest pain syndromes.

Adult↗
PubMed1979

Profiles of radionuclide left ventricular ejection fraction changes induced by supine bicycle exercise in normals and patients with coronary heart disease.

This paper presents the profiles of left ventricular ejection fraction (EF) during and following supine bicycle exercise in normal subjects and in patients with coronary heart disease, as well as the relationship of the described patterns to clinical parameters. Twenty normal men and 40 patients with coronary artery disease were studied using gated equilibrium radionuclide angiography (EQ-EF). In the normals, during exercise, EF increased by a mean of 25% of the resting value, with an increase of no less than 11%. The exercise-limiting symptom in patients with coronary artery disease was angina pectoris in 20 and fatique in the other 20 patients. In the angina patients, there was a mean decrease in EF of 20%, and in the other coronary artery disease patients ejection fraction change little. Only two patients with coronary artery disease increased from a normal resting value to peak exercise by more than 11%, and they had isolated right coronary lesions. An "overshoot" elevation of ejection fraction above resting levels was demonstrated following termination of exercise in most patients. The patients with a significant fall in exercise ejection fraction more frequently had abnormal exercise-induced ECG changes as well as abnormal left ventriculograms and more severe coronary artery disease at cardiac catheterization than the patients with little change in ejection fraction. We conclude that 1) normals could be separated from most patients with significant coronary artery disease in this study population; 2) ejection fraction must be measured at maximal exercise for it to have diagnostic value, since there could be normal rise before and after peak exercise and an abnormal response missed; and 3) the ejection fraction response to exercise reflects the severity of the underlying coronary artery disease. The described patterns of exercise-induced changes in left ventricular ejection fraction are important to consider when using this new technique to diagnose and evaluate patients with coronary artery disease.

Adult↗
PubMed1979

Assessment of early ventricular systole by first pass radionuclide angiography: useful method for detection of left ventricular dysfunction at rest in patients with coronary artery disease.

To identify abnormal left ventricular function without exercise stress in patients with coronary artery disease first-pass radionuclide angiograms were analyzed in 32 normal subjects (Group I); 31 patients with coronary disease and normal contrast ventriculograms (Group II); and 17 patients with coronary disease and depressed left ventricular function (Group III). Total ejection fraction (EF) was computed with standard angiographic methods and from each time-activity curve. During the first third of systole, ejection fraction was determined manually by averaging three to five beats and the value compared with that obtained with contrast ventriculography: (Formula: see text). Both total radionuclide ejection fraction (r = 0.95) and first-third ejection fraction (r = 0.91) correlated well with angiography. Intraobserver and interobserver variation was small, averaging 0.02 +/- 0.02 (range 0 to 0.05). The radionuclide first-third ejection fraction was 0.25 or greater in normal subjects and less than 0.25 in 29 of 31 patients (94 percent) in Group II and in all patients in Group III. It is concluded that the first-third ejection fraction obtained with first pass angiography identifies subtle abnormalities of left ventricular function at rest in more than 90 percent of patients with coronary disease that may not be recognized by total ejection fraction alone.

Adult↗