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Biomedical subjects

C Shub

Publications and source records attributed to C Shub.

At least 37 records · Page 2Linked to original sources
PubMed1990

Cardiology patient simulator and computer-assisted instruction technologies in bedside teaching.

The design and uses of an innovative technology-based approach which addresses critical problems with bedside teaching during ward rounds in the current health care situation are described. A cardiology patient simulator (HARVEY) and an accompanying computer-based interactive laserdisk system provide medical students, house officers and other health professionals with the opportunity to encounter a wide variety of clinical problems for learning and assessment. A group of cardiologists and medical educators from a consortium of US medical schools has guided the development and formal assessment of the entire system over the past 10 years. The system and simulator can be configured and programmed to provide appropriate heart sounds, laboratory data, and test results upon request; hands-on experience to practise examination skills is also available. The system, whole or in part, can be used in a variety of instructional modes from self-instruction to demonstration teaching, and from self-assessment to the final clinical examination. The system's effectiveness for teaching medical clerks is summarized, as is its use in providing continuing education for primary care doctors in rural practice.

Cardiology↗
PubMed1989

Utility of color flow imaging for visualizing shunt flow in atrial septal defect.

Color flow imaging provides visualization of intracardiac blood flow. The usefulness of this technique was evaluated in 93 patients with atrial septal defect. Color flow imaging improves the sensitivity of two-dimensional Doppler echocardiography in the diagnosis of atrial septal defect. In addition, it enhances communication between the cardiologist and the cardiovascular surgeon.

Adolescent↗
PubMed1989

Preoperative assessment of cardiac patients undergoing noncardiac surgical procedures.

A careful clinical history and physical examination are the most important components of the preoperative assessment of the cardiac patient who is to undergo a noncardiac surgical procedure. From these factors and the nature of the surgical procedure planned, a reasonable estimate of potential cardiac risk can be formulated to guide judicious preoperative testing for further definition of potentially high-risk patients. The potential risks associated with an invasive cardiac procedure or surgical intervention must always be considered along with the potential benefits of such a procedure in an attempt to reduce the cardiac risk of noncardiac operations. Aggressive and conscientious preoperative assessment and perioperative care of the high-risk patient by the concerted efforts of the medical consultant, anesthesiologist, and surgeon may substantially diminish cardiac-related morbidity and mortality during noncardiac surgical procedures.

Aged↗
PubMed1989

Hypertension and left ventricular diastolic function.

In recent years, there has been increased recognition of the relative importance of abnormalities of diastolic function in patients with essential hypertension. Indeed, diastolic dysfunction may be the earliest indicator of hypertensive heart disease. In this article, the mechanisms governing normal ventricular relaxation and the factors that may cause diastolic dysfunction are reviewed. Noninvasive clinical methods, particularly Doppler echocardiography and radionuclide angiography, for determination of diastolic function are outlined, and the limited experience in the management of hypertensive patients with abnormalities of diastolic function is discussed. When congestive heart failure develops in a patient with hypertension, it is especially important to determine whether it is due primarily to systolic or to diastolic left ventricular dysfunction.

Adrenergic beta-Antagonists↗
PubMed1989

Risk of noncardiac surgical procedures in patients with aortic stenosis.

Although severe aortic stenosis has been reported to increase the risk of noncardiac operation, recent advances in anesthetic management may alter this risk. We reviewed the perioperative course of 48 consecutive patients (mean age, 73 years) with significant aortic stenosis who underwent a noncardiac operation or diagnostic procedure between 1985 and 1987. Twenty-five patients had local anesthesia with intravenous sedation, 22 (17 with severe and 5 with moderate aortic stenosis) underwent general anesthesia, and 1 had spinal anesthesia. Of the 48 patients, 36 (75%) had symptoms--congestive heart failure in 24, angina in 19, and syncope in 7. Doppler echocardiography, performed in all 48 patients, revealed a mean peak instantaneous gradient of 76 mm Hg and a calculated aortic valve area (in 22 patients) of 0.61 cm2. In the 20 patients who also underwent preoperative cardiac catheterization, the calculated mean aortic valve area was 0.59 cm2. Seven patients had one or more perioperative events, including intraoperative hypotension in five; all except one of these events were transient and without major sequelae. No intraoperative deaths occurred. Selected patients with severe aortic stenosis can undergo noncardiac procedures at a reasonably low risk with careful monitoring of anesthesia.

Aged↗
PubMed1989

A novel approach to atrial endocardial pacing.

We describe a patient who had tricuspid valve replacement and in whom dual-chamber pacing was accomplished by using a ventricular epicardial lead and by placing an atrial endocardial lead through the wall of the atrial appendage and positioning the tip against the endocardial surface of the atrial appendage. A ligature was placed around the atrial appendage where the lead passed through the wall of the right atrial appendage. This obviated the need for a second procedure to place the atrial lead in a transvenous fashion. After 5 years of follow-up the patient continues with normal DVI pacing.

Aged↗
PubMed1988

Correlation between verapamil plasma concentration and P-R prolongation in essential hypertension.

Plasma verapamil concentration was correlated with serial electrocardiographic P-R intervals in patients with essential hypertension receiving immediate-release (80 to 120 mg three times a day) or sustained-release (240 mg daily) verapamil. The mean P-R interval in 22 patients taking placebo and immediate-release verapamil was 0.18 second. The borderline first-degree atrioventricular block of three patients did not change during treatment. Plasma verapamil concentrations of patients with a P-R interval longer than 0.20 second and of those with a P-R interval of 0.20 second or less were 169 +/- 73 ng/mL and 63 +/- 8 ng/mL, respectively. Six patients taking sustained-release verapamil had a maximal mean P-R interval of 0.19 +/- 0.01 second during 24-hour ambulatory electrocardiographic monitoring. P-R intervals were 0.22 second or more in two patients, but they returned to normal by hour 7 for one and by hour 20 for the other patient. In summary, transient P-R prolongation occurred with oral verapamil therapy, but no patient, regardless of baseline P-R interval, developed high-grade atrioventricular block.

Delayed-Action Preparations↗
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↗
PubMed1987

To anticoagulate or not: implications for the management of patients with acute myocardial infarction complicated by both left ventricular thrombus and pericardial effusion.

We reviewed the clinical and echocardiographic characteristics of seven patients with left ventricular thrombus and pericardial effusion. Each patient had a recent anterior wall myocardial infarction with an apical left ventricular thrombus. Two patients had clinical evidence of pericarditis. On two-dimensional echocardiography, the effusion was judged to be small in five cases and moderate in two. All patients received parenteral heparin therapy; six of the seven patients subsequently received long-term oral anticoagulation therapy. None of the patients had any clinical or two-dimensional echocardiographic evidence of increasing pericardial effusion or tamponade. Documented systemic embolization was seen in only one patient, whose anticoagulant therapy was stopped 2 weeks after myocardial infarction. In five patients, repeat two-dimensional echocardiography was performed from 2 to 4 months after infarction; in four patients, neither pericardial effusion nor left ventricular thrombus was found. In this group of patients, both short- and long-term anticoagulants were safely administered despite pericardial effusion.

Aged↗
PubMed1986

Spectrum of cardiac involvement in Friedreich's ataxia: clinical, electrocardiographic and echocardiographic observations.

Combined 2-dimensional and M-mode echocardiography was used to assess the cardiac status of 22 patients with Friedreich's ataxia, and the findings were correlated with the clinical and electrocardiographic (ECG) data. Mean age at onset of Friedreich's ataxia was 8 years (range 3 to 18); mean age at echocardiography was 18 years (range 8 to 39). Echocardiographic findings were abnormal in 19 patients (86%). The 3 patients with normal echocardiographic findings did not have cardiac symptoms, but 1 had ECG repolarization abnormalities. Concentric left ventricular (LV) thickening, the most common echocardiographic finding, was found in 15 patients (68%) and in all 15 the papillary muscles were thickened. These 15 patients had ECG repolarization abnormalities and 5 had left-axis deviation; however, only 3 satisfied ECG criteria for LV or right ventricular hypertrophy. Two of the 15 patients (9%) had symptoms of heart failure. Two patients had asymmetric septal thickening without clinical evidence of LV outflow tract obstruction; neither had cardiac symptoms, but both had ECG repolarization abnormalities. Two patients showed a dilated cardiomyopathy pattern; both had heart failure and atrial flutter. One of these patients died, and necropsy revealed 4-chamber cardiac dilatation, biventricular hypertrophy and histologic findings of diffuse interstitial fibrosis, myocellular hypertrophy and necrosis. This study revealed a wide spectrum of cardiac abnormalities in patients with Friedreich's ataxia.

Adolescent↗
PubMed1986

Echocardiographic findings in pheochromocytoma.

M-mode and 2-dimensional echocardiography were used to study 26 consecutive, unselected patients with pheochromocytoma over a 3-year period. Only 1 patient had congestive heart failure; more than half had no cardiac symptoms or abnormalities. The most common (80% of patients) echocardiographic pattern was normal left ventricular (LV) mass with normal or even increased systolic performance. When LV mass was increased, LV systolic function was either normal or only borderline depressed in most of the patients. Patients with echocardiographic LV hypertrophy had symmetric thickening of ventricular walls; no case of asymmetric septal hypertrophy was found. There was no correlation between 24-hour urinary norepinephrine excretion and any of the echocardiographic variables studied. In some patients, increased LV wall thicknesses did not correlate with increased LV mass as calculated by the Woythaler echocardiographic method. Left atrial enlargement was not seen in any patient, including those with increased LV mass. The electrocardiogram and echocardiogram may be discordant: Electrocardiographic LV hypertrophy was seen in 6 patients, of whom 5 had normal echocardiographic LV mass. In patients with pheochromocytoma who have no cardiac symptoms or other clinical evidence of cardiac involvement, echocardiographic findings are usually normal.

Adrenal Gland Neoplasms↗
PubMed1986

Antihypertensive efficacy of pinacidil--automatic ambulatory blood pressure monitoring.

Forty-three patients with mild essential hypertension were randomized into two double-blind studies: pinacidil vs. placebo or pinacidil vs. hydralazine. Pinacidil (62 +/- 18 mg/day) decreased office systolic and diastolic blood pressures from 145 to 137 mm Hg and from 98 to 89 mm Hg, respectively, after 6 weeks of therapy. Similarly, hydralazine (128 +/- 28 mg/day) reduced supine systolic blood pressure from 140 to 134 mm Hg and supine diastolic blood pressure from 93 mm Hg to 84 mm Hg. Significant tachycardia was not noted with either drug. Ambulatory blood pressure was monitored for 24 h during the placebo-washout and efficacy phases with both pinacidil and hydralazine. Mean 24-h blood pressure was 128 systolic and 81 diastolic with pinacidil and 121 systolic and 76 diastolic with hydralazine. Reduction in awake hypertensive diastolic blood pressure was significant for both pinacidil and hydralazine. Normal sleep diastolic blood pressure was not reduced by pinacidil but was reduced by hydralazine. Side-effects with both drugs included edema, headache, and palpitations. These data demonstrate that pinacidil is as effective an antihypertensive agent as hydralazine.

Adult↗
PubMed1985

Echocardiographically documented mitral-valve prolapse. Long-term follow-up of 237 patients.

We determined the long-term prognosis for patients with mitral-valve prolapse documented by echocardiography by following 237 minimally symptomatic or asymptomatic patients for a mean of 6.2 years (range, 1 to 10.4). The actuarial eight-year probability of survival was 88 per cent, which is not significantly different from that for a matched control population. An initial left ventricular diastolic dimension exceeding 60 mm was the best echocardiographic predictor of the subsequent need for mitral-valve replacement (17 patients). Of the 97 patients with redundant mitral-valve leaflets identified echocardiographically, 10 (10.3 per cent) had sudden death, infective endocarditis, or a cerebral embolic event; in contrast, of the 140 patients with nonredundant valves, only 1 (0.7 per cent) had such complications (P less than 0.001). Most patients with echocardiographic evidence of mitral-valve prolapse have a benign course, but subsets at high risk for the development of progressive mitral regurgitation, sudden death, cerebral embolic events, or infective endocarditis can be identified by echocardiography.

Adolescent↗
PubMed1985

Two-dimensional echocardiographically guided pericardiocentesis: experience in 117 consecutive patients.

Pericardiocentesis guided by 2-dimensional echocardiography has been used at the Mayo Clinic since April 1980. The 2-dimensional examination localizes the pericardial fluid. Particular note is made of the place on the body wall closest to the fluid. An entry track that permits puncture of the pericardial sac without damage to any vital structure is then selected for the pericardiocentesis needle. Between April 1980 and March 1984, 132 consecutive pericardiocenteses in 117 patients were done by this technique. The volume of fluid obtained ranged from 75 to 1,700 ml (mean 650). Seventy percent of the taps were done for therapy, 21% for diagnosis, and 9% for both therapy and diagnosis. A Teflon-sheathed "intracath" needle was used to complete 80% of the pericardiocenteses. In the other 20%, a large catheter was secondarily introduced and connected to a closed drainage system. There were no deaths related to the procedure. One symptomatic pneumothorax occurred. There were 3 minor complications. Two-dimensional echocardiographic imaging of the heart and pericardial fluid permits a safe and effective means of performing pericardiocentesis.

Adolescent↗
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↗