Search PubMed⌕ Search

Biomedical subjects

V Froelicher

Publications and source records attributed to V Froelicher.

89 records · Page 5Linked to original sources
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

Radionuclide perfusion images before and after cardiac rehabilitation.

Improvement in cardiac perfusion has not been demonstrated in man to explain the increased functional capacity secondary to exercise training. Thallium imaging is a noninvasive method of evaluating myocardial perfusion and scaring. Therefore, using thallium exercise tests, we studied 17 patients with coronary heart disease before and after a mean of 6 months participation in cardiac rehabilitation program emphasizing exercise training. Interobserver variability in imaging interpretation was considered by reading images blinded both individually and in consensus. Agreement with defects called by consensus occurred at least 51% of the time individually and normal readings agreed at least 90% of the time. By consensus reading, seven patients showed improved perfusion, seven showed no change, and three worsened following training. Our study shows that thallium scans may be used to demonstrate central changes in myocardial perfusion after cardiac rehabilitation, but larger controlled studies considering redistribution and utilizing image enhancement are necessary to see if such changes are truly secondary to this intervention.

Adult↗
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

Reproducibility of ejection-fraction determinations by equilibrium radionuclide angiography in response to supine bicycle exercise: concise communication.

Sixteen patients with stable, chronic coronary artery disease were studied twice within and average of 15 days to evaluate the reproducibility of ejection fraction (EF) determined by equilibrium radionuclide angiography (EQ) at rest, during supine bicycle exercise (ex), and in the recovery period (rec). Following injection of 20--25 mCi of Tc-99m-tagged human serum albumin, data were analyzed for 2-min periods at rest, during several stages of exercise (submax, max), and during recovery (rec1 = minutes 2 + 3, rec2 = minutes 9 + 10). Each patient reached similar (heart rate) X (blood pressure) products in the two studies: 21280 +/- 5200 compared with 20390 +/- 4140 mmHg/min. Mean EFs for the first and second studies were: at rest (53.0 +/- 10.8)%, 52.5 +/- 10.4)% (r = 0.95; submax ex (51.4 +/- 12.0)%, (52.1 +/- 12.8)%, (r = 0.91); max ex (50.6 +/- 12.6)%, (51.6 +/- 12.9)% (r = 0.97); rec1 (62.7 +/- 11.6)%, (62.4 +/- 12.2)% (r = 0.95); rec2 (55.5 %/- 10.8)%, (57.2 +/- 11.7)% (r = 0.91). In stable patients, the reproducibility of EF determined by EQ is excellent during rest, supine bicycle exercise, and recovery from exercise.

Adult↗
PubMed1979

[Diagnosis of coronary artery disease: value and limitations of non-invasive methods. (Ecg, thallium perfusion scintigraphy, radionuclide angiography) (author's transl)].

In order to compare the three non-invasive exercise tests Ecg, Thallium myocardial perfusion imaging and radionuclide angiography in the diagnosis of coronary artery disease, the results of these tests in a consecutive series of 30 patients and 14 controls were analyzed. In all 88 symptom-limited exercise tests a significantly higher double product (heart rate x systolic blood pressure, mm Hg/min) was reached on a treadmill test (for Ecg and Thallium scintigraphy) as compared to the supine bicycle ergometer exercise (for radionuclide angiography: 243.1 +/- 61.1 vs. 215.2 +/- 46.5 x 10(2) (p less than 0.01). Considering all 132 diagnostic tests the overall sensitivity for rest/exercise Ecg was 67%, for Thallium scans 77%, for both combined 83% 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 60% (Ecg), 47% (Thallium scans), 70% (both tests combined) and 97% (radionuclide angiography). The specificity for coronary artery disease was determined to be 79% for Ecg, 86% for Thallium scintigraphy, 64% for Ecg/Thallium scans and 71% for radionuclide angiography. The most common reason for a false-positive result in all tests was found to be the diagnosis of cardiomyopathy, whereas most false-negative results were seen in patients with single vessel right coronary artery disease. Based on these results, the clinical implications of the three non-invasive tests in the diagnosis of coronary artery disease are discussed.

Adult↗
PubMedDate not supplied

Review of studies using multivariable analysis of clinical and exercise test data to predict angiographic coronary artery disease.

Multivariable analysis of clinical and exercise test variables has the potential to become both a useful tool for assisting in the diagnosis of coronary artery disease and reducing the cost of evaluating patients with suspected coronary disease. Managed care and capitation require that tests such as the exercise test or its replacements, be used only when they can accurately and reliably identify which patients need medications, counseling, or further evaluation or intervention. The replacements for the standard exercise electrocardiogram test require expensive equipment and personnel, and their incremental value is currently being evaluated. Because general practitioners are to function as gatekeepers and decide which patients must be referred to the cardiologist, they will need to use the basic tools they have available (ie, history, physical exam, and the exercise test) in an optimal fashion. However, the discriminating power of the variables from the medical history and exercise test remains unclear because of inadequate study design and differences in study populations. There is a need for further evaluation of these routinely obtained variables to improve the accuracy of prediction algorithms especially in women. Of paramount concern is the need to avoid workup bias by having patients agree to testing before the decision for angiography is made. The portability and reliability of these equations must be shown because access to specialized care must be safeguarded. By reviewing the available studies considering clinical and exercise test variables to predict coronary angiographic findings, we have attempted to provide guidelines and recommendations for a more uniform approach to this endeavor in future investigations. Hopefully, the next generation of multivariable equations will be robust and portable, and empower the clinician to assure the cardiac patient access to appropriate cardiac care.

Coronary Angiography↗
PubMedDate not supplied

Management of the patient with congestive heart failure using outpatient, home, and palliative care.

Congestive heart failure is a chronic, debilitating illness, with increasing prevalence in the elderly. It is one of the most common causes for hospital admission, and associated treatment costs are estimated at $20.2 billion. Despite improved survival with medical therapy, beneficial effects on quality of life have not been consistently reported. In addition, optimum medical therapy, as recommended by evidence-based guidelines, are not always implemented. Counseling and education involving dietary modifications, activity recommendations, medication management, self-monitoring, prognosis, coping skills, social support, caregiver stress, and spiritual needs are critical components in the management of heart failure through initial diagnosis to end of life. Within the last decade, close follow-up for congestive heart failure has been associated with decreased hospitalizations, reduced hospital length of stay, improved functional status, better compliance, lower costs, and improved survival. Research trials have mainly been observational and small, and they have used different interventions. Little has been written regarding outpatient management of the patient with advanced congestive heart failure, and none of the current published guidelines addresses recommendations for the New York Heart Association class IV (other than for transplant candidacy). New models of close follow-up for chronic and advanced congestive heart failure should be investigated. These models could be implemented in urban and rural settings and be supported by private insurance or Medicare.

Ambulatory Care↗
PubMedDate not supplied

An evidence-based review of the resting electrocardiogram as a screening technique for heart disease.

Given renewed interest in the primary prevention of cardiovascular disease, we comprehensively reviewed the utility of the electrocardiogram (ECG) for screening considering the seminal epidemiologic studies. It appears that conventional risk factors relate to long-term risk, while ECG abnormalities are better predictors of short-term risk. For individual ECG abnormalities as well as for pooled categories of ECG abnormalities, the sensitivity of the ECG for future events was too low for it to be practical as a screening tool. This almost certainly relates to the low prevalence of these abnormalities. However, all ECG abnormalities increase with age and pre-test risk. Also screening with the ECG is of minimal cost and likely to decrease further as stand-alone machines are replaced by integration into personal computers (PC). Another potential impact on performing screening ECGs would be distribution and availability of digitized ECG data via the World Wide Web. For clinical utility of ECG data, comparison with previous ECGs can be critical but is currently limited. PC based ECG systems could very easily replace many of the ECG machines in use that only have paper output. PC-ECG systems would also permit interaction with computerized medical information systems, facilitate emailing and faxing of ECGs as well as storage at a centralized web-server. Web-enabled ECG recorders similar to the new generation of home appliances could follow this quick PC solution. A serious goal for the medical industry should be to end the morass of proprietary ECG digital formats and follow a standardized format. This could lead to a network of web-servers from which every patient's ECGs would be available. Such a situation could have a dramatic effect on the advisability of performing screening ECGs.

Bundle-Branch Block↗
PubMedDate not supplied

The reliability of probability analysis in the prediction of coronary artery disease in two hospitals.

To assess the accuracy of the Bayesian computer program CADENZA for the prediction of coronary artery disease, the authors examined the probabilities generated by the application of this program to the clinical and noninvasive test results of 303 patients in a private referral center and 199 patients in a veterans' hospital. These probabilities were compared with those produced by applying a six-variable discriminant function derived by logistic regression at the private referral center. Two statistical approaches were employed in evaluating the relative performances of the Bayesian program and the discriminant function. The first of these involved the sorting of patients in both test groups into ascending deciles of probability and comparing expected probability with observed angiographic disease prevalence in each decile. The second involved the calculation and comparison of a standardized reliability measure. The latter was significantly lower for the discriminant function both at the private hospital (0.200 for the discriminant function versus -17.5 +/- 1.96 for the Bayesian program) and at the veterans' hospital (-0.8 +/- 1.96 for the discriminant function versus -11.3 for Bayesian program). This suggests that the discriminant function is significantly superior to the Bayesian algorithm CADENZA for predicting coronary artery disease probabilities in subjects who have relatively high pretest disease probabilities.

Bayes Theorem↗