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Biomedical subjects

G C Friesinger

Publications and source records attributed to G C Friesinger.

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

Right ventricular myocardial infarction in patients with chronic lung disease: possible role of right ventricular hypertrophy.

To determine the relation between right ventricular hypertrophy and right ventricular myocardial infarction in patients with chronic lung disease, the records of 28 patients with chronic lung disease, inferior myocardial infarction and significant coronary artery disease (group I) and 20 patients with right ventricular hypertrophy, chronic lung disease without inferior myocardial infarction or significant coronary artery disease (group II) were reviewed. Chronic lung disease was diagnosed by clinical criteria, chest radiographs and pulmonary function tests. All patients had postmortem examinations. Patients in group I were classified into two subgroups: group Ia (without right ventricular hypertrophy) and group Ib (with right ventricular hypertrophy). Right ventricular wall thickness was 3.3 mm +/- 0.5 in group Ia, 6.0 mm +/- 1.1 in group Ib and 8.8 mm +/- 2.4 in group II (group Ia versus Ib, p less than 0.001; group Ia versus II, p less than 0.001; group Ib versus II, p less than 0.001). Eleven patients (78.6%) in group Ib (chronic lung disease with both right ventricular hypertrophy and inferior myocardial infarction) had right ventricular myocardial infarction compared with only 3 patients (21.9%) in group Ia (chronic lung disease without right ventricular hypertrophy and with inferior myocardial infarction) (p less than 0.008). Isolated right ventricular myocardial infarction occurred in four patients (20%) in group II (chronic lung disease with right ventricular hypertrophy, but without evidence of infarction of the left ventricle or significant coronary artery disease). There was no significant difference in the extent of anatomic coronary disease in groups Ia and Ib.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Reduction of infarct size with intracoronary perfluorochemical in a canine preparation of reperfusion.

The effect of low-dose (15 ml/kg) intracoronary perfluorochemical (Fluosol-DA) on infarct size, regional myocardial blood flow, and ventricular function was studied in 20 anesthetized closed-chest dogs subjected to 11/2 hr of proximal left anterior descending occlusion. In this preparation reperfusion was simulated with fibrinolytic therapy. The animals were randomly assigned one of two treatment groups and given 15 ml/kg of either oxygenated intracoronary perfluorochemical (n = 9) or saline (n = 11). Contrast ventriculograms were obtained at baseline, 1 hr after occlusion, and at 24 hr after reperfusion and were analyzed with a radial fractional shortening method. Regional myocardial blood flow was measured with radioactive microspheres. At 24 hr the area at risk was defined in vivo with monastryl blue staining and the area of necrosis was estimated after incubation of left ventricular slices with triphenyltetrazolium chloride. No significant changes were noted in heart rate, blood pressure, pulmonary capillary wedge pressure, or dP/dt during the experimental protocol. Infarct size was significantly reduced (p less than .02) in the perfluorochemical-treated group, both when expressed as a percentage of the total left ventricular mass (7.9 +/- 1.7% vs 14.7 +/- 2.5%) and as a percentage of the area at risk (20.1 +/- 5.0% vs 46.8 +/- 8.5%). This was associated with significant improvement in fractional shortening in the jeopardized zone at 24 hr after reperfusion. Although endocardial blood flow was significantly greater in the central ischemic zone and lateral region at risk immediately after reperfusion in the perfluorochemical-treated group, no difference was found 1 hr after reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Pseudoaneurysm of the left ventricle. Diagnosis by first pass scintigraphy.

False aneurysm of the left ventricle is a rare complication of myocardial infarction with a high propensity for late rupture. Timely diagnosis is important and surgical repair is curative in a high percentage of patients. A case in which a false left ventricular aneurysm was recognized by first pass radionuclide angiography and confirmed by contrast ventriculography is reported. Surgery was then performed successfully. The diagnosis of false left ventricular aneurysm using radionuclide angiography, as well as other diagnostic imaging modalities, is discussed.

Heart Aneurysm↗
PubMed1983

Evaluation of left ventricular performance using digital subtraction angiography.

Cardiac applications for digital subtraction angiography appear promising, but few correlative studies with contrast ventriculography have been done. Left ventricular volume, ejection fraction, and regional wall motion by digital subtraction angiography were evaluated after intravenous injection of 40 ml of iodinated contrast medium and after left ventricular injection of 5 to 10 ml of contrast medium. A film-based system of the authors' own design was used. Results were compared with those after direct left ventricular injection of 40 ml of contrast medium. The ventriculograms after intravenous injection were of diagnostic quality in 9 of 12 studies, and there were close correlations between intravenous and direct-injection studies for left ventricular ejection fraction (r = 0.89, n = 9, and p = 0.001) and for left ventricular volume (r = 0.91, n = 18, and p less than 0.001). Regional wall motion scores showed close correspondence in 83% of sectors. After small-volume left ventricular injections, the ventricular image was enhanced considerably by digital subtraction. Correlations between small- and large-volume ventriculograms were close for left ventricular ejection fraction (r = 0.91, n = 8, and p = 0.002) and for left ventricular volume (r = 0.96, n = 16, and p less than 0.001). There was close correspondence of wall motion scores in 87% of sectors. Thus, digital subtraction angiography improves the visibility of the left ventricle after either intravenous or small-volume direct left ventricular injection. Digital images produce excellent estimates of left ventricular volume and should have considerable usefulness for the study of cardiac performance and anatomy.

Adult↗
PubMed1983

Assessment of ventricular size and function in congenitally corrected transposition of the great arteries.

Twenty-four quantitative cineangiographic studies were performed in 19 patients with congenitally corrected transposition of the great arteries to assess right and left ventricular size and function. Ages ranged from 7 days to 44 years and associated lesions included ventricular septal defect (13 of 19), pulmonary stenosis (9 of 19), and systemic (tricuspid) valvular insufficiency (7 of 19). Systemic (anatomically right) ventricular end-diastolic volume was within normal limits in most patients and averaged 119% of predicted normal. Pulmonary (anatomically left) ventricular end-diastolic volume also was normal in most patients, averaged 112% of predicted, and was not different from systemic (right) ventricular end-diastolic volume. Systemic ventricular ejection fraction (RVEF) averaged 0.61 +/- 0.02 and was not different from pulmonary ventricular ejection fraction (LVEF) (0.65 +/- 0.02), but important differences were apparent when age was considered. With exclusion of 2 patients with hypoplastic systemic ventricles and 2 studies performed less than 6 months after open heart surgery, all 12 patients aged less than 10 years had a normal RVEF, whereas 2 of 5 patients aged greater than 17 years had a definitely low RVEF and 1 of 5 had a value at the lower limit of normal. In children, systemic and pulmonary ventricular pump function is usually normal in congenitally corrected transposition of the great arteries and any deviation from normal should suggest ventricular hypoplasia or an increase in afterload. After childhood, systemic ventricular dysfunction is more common and may reflect the inability of the anatomic right ventricle to function as the systemic pumping chamber over a normal lifetime in most patients with congenitally corrected transposition of the great arteries.

Adolescent↗
PubMed1983

Left ventricular performance after coronary artery bypass surgery. Prediction of functional benefit.

Global left ventricular performance (ejection fraction) and regional function were studied by rest-exercise radionuclide ventriculography in 36 patients before and after (23 +/- 8.5 wk) they had coronary artery bypass surgery for stable angina pectoris. The exercise ejection fraction was less than the resting ejection fraction before surgery (n = 36,p = 0.006), but not after surgery. The degree of postoperative improvement correlated with the degree of preoperative dysfunction (r = 0.55, n = 36, p less than 0.001). Improvement was most likely to occur if exercise-induced dysfunction was present preoperatively (n = 15,p = 0.001), even with old myocardial infarction. Regional dysfunction during preoperative exercise was also likely to improve postoperatively (n = 18, p = 0.001). Protocol design is important in determining the results and their interpretation. Matching postoperative exercise loads to preoperative loads and using regional analysis with two imaging projections improved judgment of the results. Regional dysfunction was commoner than global dysfunction and was less sensitive to workloads than was ejection fraction. This study shows that coronary artery bypass surgery can improve left ventricular performance on exercise if preoperative tests indicate the presence of ischemia-induced dysfunction.

Adult↗
PubMed1983

Optimal resources for examination of the heart and lungs: cardiac catheterization and radiographic facilities. Examination of the Chest and Cardiovascular System Study Group.

This is a revision of the 1976 report published under the auspices of the Inter-Society Commission for Heart Disease Resources. These guidelines provide a description of optimal resources, personnel, and working arrangements and should not be used to set minimal, standard, or uniform criteria or practices for all institutions. Included in the report are specifications for radiologic and physiologic equipment, description of case loads for maintaining safe and effective performance and considerations or complication rates. Also discussed are professional staff qualifications and relationships between physicians and technical and administrative services personnel. Other topics reviewed included laboratory location, electrical safety, and radiation protection as well as optimal facilities and equipment criteria for conventional x-rays. Newer imaging modalities are briefly considered, primarily to to emphasize that the field is rapidly changing. It is not possible, however to make specific recommendations concerning how these modalities will complement and/or replace more conventional techniques and approaches now considered appropriate and optimal.

American Heart Association↗
PubMed1982

Randomized double-blind study of pindolol in patients with stable angina pectoris.

Twelve patients with documented coronary arteriosclerosis and severe stable angina pectoris were treated with the beta blocker pindolol, 5 mg four times a day, utilizing a double-blind crossover protocol. Following 4 weeks of baseline observation with no active treatment, pindolol and placebo were given for 4 weeks each. End points evaluated were episodes of angina pectoris/week, number of nitroglycerin tablets used per week, time on treadmill test until onset of angina pectoris, double product of heart rate and blood pressure at onset of angina pectoris, and amount of ST depression during the treadmill exercise test. Episodes of angina pectoris and nitroglycerin consumption were reduced by 18% on placebo and 32% on pindolol (not significant). All of the improvement occurred in the third and fourth weeks of pindolol treatment. Less difference between pindolol and placebo was noted when the placebo period came after the pindolol period, suggesting a carry-over effect of pindolol. With pindolol, treatment exercise tolerance was increased 13% (33 seconds) over baseline levels but only 2% over the levels achieved with placebo treatment (not significant). ST depression with exercise was 6% less when patients were on pindolol than when they were on placebo (not significant). There was a marked decrease in myocardial oxygen demand as measured by the double product of blood pressure and pulse during exercise (23% reduction when on pindolol and no change when on placebo, p less than 0.01). This study shows that there was an important placebo effect when treatment of angina pectoris was evaluated and that pindolol significantly reduced myocardial oxygen demand but evidence of ischemia was not significantly reduced. Possible mechanisms to explain the disparity between reduction in estimated myocardial oxygen demand (double product) and objective improvement in ischemia include coronary spasm and altered regional flow resulting from beta blockade. Alternative explanations may be the relatively small fixed dose of pindolol and the small number of patients studied.

Adult↗
PubMed1982

Variability of response to beta receptor blockade for angina pectoris in clinical trials: a study of pindolol.

In a randomized, controlled study we found a significant decrease in pressure-rate (double) product and an improvement in exercise tolerance in patients with angina pectoris treated with pindolol. However, when patients were observed in a long-term double-blind crossover study, pindolol treatment did not produce a significant improvement in angina pectoris or exercise tolerance over placebo. Patients treated with placebo had a gradual improvement in exercise tolerance, possibly because of the training effect of multiple treadmill tests and increased daily walking. The individual patient response to pindolol varied, with some patients showing clinical improvement and decreased double product with exercise and some having no clinical improvement despite a similar decrease in double product. Angina occurred at a lower double product with exercise, suggesting that beta receptor blockade adversely affected other variables of myocardial oxygen demand or decreased coronary blood supply. This study illustrates the difficulties with patient variability and study design that are encountered in studies of beta blocker agents for angina pectoris.

Adrenergic beta-Antagonists↗
PubMed1982

Radionuclide ventriculography: evaluation of automated and visual methods for regional wall motion analysis.

Regional wall motion (RWM) abnormalities are sensitive indicators of left ventricular (LV) dysfunction, but quantitation of RWM with gated radionuclide ventriculography (RVG) has been limited, particularly in the left anterior oblique (LAO) projection. Regional LV performance was studied in 18 patients undergoing LAO RVG immediately prior to contrast ventriculography (CVG). Wall motion was analyzed by semiautomated and visual methods using several coordinate systems. For semiautomated methods, RVG and CVG wall motion were closely related in the two 90 degrees polar sectors at the apex and posterior wall (r = .85) and in the five 45 degrees polar sectors from midseptum through posterior wall (r = .82). The basal sectors on RVG had weak relationship to CVG, due to adjacent vascular structures. Semiautomated and visual grades for polar sectors on both CVG and RVG were closely related (r = .88- .94). Measured regional wall motion on LAO RVG compared favorably with near-simultaneous CVG in nonoverlapping portions of the LV and allowed objective quantitation of regional LV performance.

Adult↗
PubMed1982

The reasonable workup before recommending medical or surgical therapy: an overall strategy.

The workup of a patient with chronic ischemic heart disease (IHD) before the selection of medical-surgical or medical therapy depends on multiple objective and subjective factors. These include symptoms, extent of anatomic disease (degree of coronary arteriosclerosis and left ventricular abnormalities), objective evidence of ischemia, extent of left ventricular dysfunction, and recent intercurrent ischemic events. In a minority of patients, a single factor is of overwhelming importance; e.g., the presence of severe left main coronary artery narrowing in a symptomatic patient indicates surgery is a better choice, whereas evidence of advanced left ventricular dysfunction suggests that surgery is likely to be risky and of limited help to the patient. In most instances, multiple factors should be considered before making a recommendation. The patient should be placed in the appropriate clinical subset and the objective factors that are most important in determining survival should be evaluated. Hence, an exercise electrocardiographic study to evaluate symptoms and exercise tolerance in a patient with angina pectoris and radioventriculographic studies with exercise to estimate left ventricular performance in a patient who complains of fatigue and breathlessness are superior to the subjective interpretations of routine clinical examinations. Asymptomatic patients and those with excellent exercise tolerance pose the most difficult decisions. Perhaps serial (even annual) noninvasive evaluation is appropriate in such patients in light of the current uncertainty about how to manage them. Laboratory tests should be used selectively, systematically and sequentially. The high cost of many of the examinations is reason to avoid duplication. When noninvasive evaluation can answer the question being posed and the cost of hospitalization avoided, this should be done. However, there is little reason to perform noninvasive examinations that do not answer the clinical question being asked; hence, in many patients it is appropriate to proceed directly to coronary arteriography rather than to perform a variety of "screening" examinations before this procedure.

Angina Pectoris↗
PubMed1982

Thallium-201 uptake in variant angina: probable demonstration of myocardial reactive hyperemia in man.

Myocardial thallium scintigraphy was performed in four subjects with variant angina and in one subject with isolated, fixed coronary obstruction. Three subjects with variant angina had short episodes of ischemic ST-segment elevation that lasted 20--100 seconds. Thallium scintigrams demonstrated excess uptake in regions judged to be ischemic by angiographic and electrocardiographic criteria. Two subjects, one with variant angina and the other with a fixed coronary lesion, had prolonged episodes of ischemia that lasted 390--900 seconds. Both had reduced thallium uptake in the ischemic regions. We conclude that myocardial reactive hyperemia is the cause of excess thallium uptake in patients with variant angina who have short episodes of myocardial ischemia.

Adult↗
PubMed1982

Prognosis in chronic ischemic heart disease.

The last 20 years have provided an extraordinary amount of data contributing to an improved understanding of the prognosis of chronic ischemic heart disease. However, much remains incompletely understood. The lack of more precise knowledge about prognosis encourages fuzzy clinical thinking and seems to justify the overutilization of a variety of diagnostic and therapeutic modalities. It seems probable that the information available on many individual patients is not fully utilized in assessing prognosis more accurately. An approach is outlined which attempts to utilize clinical and laboratory data in prognosis with particular emphasis on objective information concerning left ventricular function and evidence of myocardial ischemia. The importance of transition phases in the natural history of the patient with ischemic heart disease is emphasized. Table V attempts to summarize areas of clinical research which are important if we are to gain a better understanding of the prognosis of this unusually complex clinical entity, chronic ischemic heart disease.

Chronic Disease↗
PubMed1981

Thromboxane A2 in vasotonic angina pectoris: evidence from direct measurements and inhibitor trials.

Thromboxane A2 (TxA2), an arachidonic acid metabolite causing vasoconstriction and platelet aggregation, is a putative mediator of coronary-artery vasospasm. To determine whether platelet-released TxA2 causes coronary arterial vasospasm, we measured plasma thromboxane B2 (TxB2, the inactive hydration product of TxA2) in the radial-artery and coronary-sinus blood of seven patients and performed therapeutic trials of antiplatelet agents in nine. Although coronary-sinus TxB2 levels rose from the base line approximately fivefold with spontaneous ischemia, samples drawn early in ischemia showed no rise over base-line values. Although a 150 mg dose of aspirin reduced urinary dinor-TxB2 levels by over 75 per cent, it had no effect on the course of the chronic recurrent form of angina pectoris due to vasospasm ("vasotonic angina"). Similarly, indomethacin had no effect on the frequency or duration of ischemia. TxA2 is unlikely to cause vasotonic angina, but it may be released during coronary vasospasm.

Adult↗
PubMed1981

Early operative intervention in aortic bacterial endocarditis.

Since 1974, 14 patients have required valve replacement for native aortic valve bacterial endocarditis at Vanderbilt University Medical Center. There were 7 male and 7 female patients ranging from 11 to 65 years old. Nine of the patients were less than 27 years old. All patients had congestive heart failure as a complication of the bacterial endocarditis and were in New York Heart Association (NYHA) Functional Class III or IV. Two patients were seen initially with arrhythmias, 3 had episodes of septic emboli, and 1 patient was operated on immediately after sustaining a cardiac arrest. Echocardiogram was utilized in 9 patients, and cardiac catheterization was performed in 6 patients who were suspected to have concomitant mitral valve or coronary artery disease. All patients were operated on within two weeks after the institution of antibiotic therapy, and there were no operative or early postoperatively deaths. Preoperative blood cultures were positive in 13 patients, with streptococcus cultured in 6 patients and staphylococcus in 4. Escherichia coli and enterococcus were the other pathogens cultured. All patients received antibiotics intravenously for a total of six weeks. There has been 1 late postoperative death, which occurred 2 months following operation in a patient with myocardial failure unresponsive to treatment. Two patients underwent reoperation, 1 because of a persistent aorto-right ventricular fistula and the second because of paraprosthetic aortic regurgitation. Nine patients are now in NYHA Functional Class I and 4 are in Class II.

Adolescent↗
PubMed1981

Recurrent ventricular tachycardia in the absence of overt heart disease: clinical characteristics and response to drug therapy.

Eight patients, seven of them women, have been followed up for a mean of 8.1 years (range, three to 18) with the uncommon syndrome of recurrent frequent episodes of ventricular tachycardia in the absence of overt cardiac abnormality. The mean age at diagnosis was 25 years (range, 12 to 44). Serious symptoms were common: five patients had syncope, cardiac arrest, and/or cerebrovascular accidents. Multiple measures to characterize this population, including study of symptoms, response to exercise, degree of prematurity of ventricular ectopic depolarizations, and response to antiarrhythmic drugs, showed little uniformity. An individualized approach to therapy, taking into account age and symptoms as well as frequency of arrhythmia, was used. Excellent control of arrhythmia was eventually achieved in four patients, but only after multiple drug trials (mean 5.3, range two to eight trials per patient) had been ineffective. Prognosis in this syndrome is generally good, but serious complications occur frequently enough that vigorous therapy is justified in selected patients.

Adolescent↗
PubMed1981

Comparison of radionuclide and contrast ventriculography for detection and quantitation of regions of myocardial ischemia in dogs.

Radionuclide and contrast ventriculography were evaluated for their ability to estimate myocardial ischemia. In 14 closed-chest, sedated dogs, a small and larger region of ischemia were produced by inflating balloon occluders on the left anterior descending coronary artery. The systemic arterial pressure, atrial-paced heart rate, global ejection fraction by radionuclide and contrast ventriculography, regional wall-motion abnormalities (as the percentage of abnormally contracting segments), and regional myocardial blood flow (using the microsphere technique) were measured during an initial control period, two separate ischemic periods, and a final control period. The regional ischemic weights based on myocardial blood flow ranged from 0 to 38.5 g and were grouped as zero, small (range 0 to less than 10 g, mean 3.40 g), and large regions of ischemia (greater than 10 g, mean 24.8 g). Regional wall-motion abnormalities were sensitive qualitative indicators of ischemia. Receiver operating characteristic analysis showed that both ventriculographic methods were highly sensitive, specific, and accurate for detecting regional ischemia. Contrast ventriculography was slightly superior for detecting small regions less than 4 g, but the methods were equal for regions greater than 4 g. The arterial pressure and heart rate were unchanged during ischemia. For small regions of ischemia, the global ejection fraction did not fall using either the contrast or radionuclide technique, but it fell significantly when large regions were produced. There was a quantitative relationship between the percentage of abnormally contracting segments and the grams of myocardial ischemia (for radionuclide ventriculography, r = 0.65, P = 0.003, and for contrast ventriculography, r = 0.75, P less than 0.001), but for many small regions of ischemia, wall-motion changes were greater than anticipated, suggesting hypofunction of the continguous normal tissue. This study demonstrated that both radionuclide and contrast ventriculography were quite sensitive and specific for detecting measured amounts of regional ischemia. The functional changes resulting from ischemia are quantitatively related to the extent of regional ischemia, small areas resulting in regional wall motion abnormalities, and large areas producing both reduced global ejection fraction and wall motion changes.

Animals↗