PubMed Health⌕ Search

Biomedical subjects

J S Schroeder

Publications and source records attributed to J S Schroeder.

At least 19 recordsLinked to original sources
PubMed1979

Prodromal characteristics as indicators of cardiac events in patients hospitalized for chest pain.

In an effort to determine the usefulness of prodromata for predicting a myocardial infarction, a prospective analysis was made of 211 consecutive patients with chest pain who were admitted to the Stanford University Medical Center Coronary Care Unit. In their subsequent course, 91 patients had a myocardial infarction, 102 had a myocardial infarction ruled-out, and 18 had a noncardiac etiology for their chest pain. Prodromal chest pain in the previous six months had occurred in 65% of patients and unstable angina in 61%. Infarction versus noninfarction patient groups could not be identified on the basis of prodromal ill health, chest pain, unstable angina, typical versus atypical nature of the chest pain, or activity at the onset of pain. Complaints of preceding fatigue and increased perceived stress were common in both groups. Activity at the onset of the admission chest pain was strenuous in 15% of the infarction patients and 12% of the noninfarction patients. We conclude that prodromal symptoms are common in both infarction and noninfarction patients. Although chest pain probably remains the single most frequent identifier of a new cardiac event, it is common in noninfarction patients and cannot be used alone to predict infarction or death.

Adult↗
PubMed1978

Tracheostomy and hemodynamic changes in sleep-inducing apnea.

Because pulmonary hypertension and systemic hypertension occur during sleep-induced obstructive apnea, six patients underwent overnight hemodynamic monitoring before and after tracheostomy. Variables studied included heart rate, pulmonary artery pressure, femoral artery pressure, and arterial oxygen tension (Po2). After tracheostomy, significant reductions were noted during sleep in mean pulmonary artery pressure from 45 +/- 6 mm Hg (mean +/- SEM) to 22 +/- 2 mm Hg (P less than 0.05) and in mean femoral artery pressure from 137 +/- 6 mm Hg to 97 +/- 3 mm Hg (P less than 0.005). There was also a significant increase for the group in arterial Po2 recorded during the apneic episodes from 38 +/- 3 mm Hg before tracheostomy to 71 +/- 2 mm Hg (P less than 0.001) after tracheostomy. We conclude that tracheostomy improves the hemodynamic abnormalities and hypoxemia that occur during sleep in patients with sleep-induced obstructive apnea.

Adult↗
PubMed1978

Sleep apnea syndrome in a patient with Shy-Drager syndrome.

A patient with autonomic insufficiency and extrapyramidal signs (Shy-Drager syndrome) and sleep apnea syndrome (SAS) underwent hemodynamic studies. In comparison to patients with SAS and intact autonomic reflexes, systemic hypertension was absent and marked sinus arrhythmia during sleep was blunted. Cyclical pulmonary hypertension associated with frequent apneic episodes during sleep persisted, reflecting a minor role of autonomic reflexes in the generation of this abnormality. Autopsy confirmed the Shy-Drager syndrome and multiple areas of degeneration were observed in areas of the CNS outside the medullary respiratory centers, suggesting their importance in the origin of the respiratory abnormalities in SAS.

Apnea↗
PubMed1977

Coronary bypass surgery for unstable angina pectoris. Long-term survival and function.

The first 81 patients to undergo coronary artery bypass surgery for unstable angina pectoris at Standford Hospital have been observed for a mean of 40.8 months. Surgical mortality was 8.5%, and perioperative incidence of myocardial infection was 16%. The mean 18-month follow-up showed two early cardiac deaths and 12 additional myocardial infarctions. Sixty-seven percent of the patients were angina-free, and the condition of none was worse. After a mean of 40.8 months, two late cardiac deaths and two myocardial infarctions had occurred. Complete relief of angina was present in 51%;22% had unstable or worsening angina. The probability of survival from time of operation to four months after surgery was 88.8% +/- 3.5%, and this remained unchanged until the two late deaths, which decreased survival probability to 83.8% +/- 4.8% at 43 months. The two late cardiac deaths and the 22% incidence of patients with worsening angina may reflect progression of the atherosclerotic process, late graft occlusion, or both.

Adult↗
PubMed1977

Sleep-induced apnea syndrome. Prevalence of cardiac arrhythmias and their reversal after tracheostomy.

Cardiac arrhythmias during wakefulness and sleep in 15 patients with sleep-induced obstructive apnea, and the effect of atropine and tracheostomy on these arrhythmias were studied by continuous overnight Holter electrocardiographic, respiratory and electroencephalographic recordings. Sleep was characterized by marked sinus arrhythmia in 14, extreme sinus bradycardia ( less than 30 beats/minute) in six, asystole of 2.5 to 6.3 seconds in five, second degree atrioventricular (A-V) block in two, and ventricular arrhythmias--complex premature ventricular beats in 10 and ventricular tachycardia in two. Arrhythmias during wakefulness were limited to premature ventricular beats in six. Atropine administration was partially and tracheostomy highly effective in preventing the majority of these arrhythmias during sleep. Marked sinus arrhythmia during sleep is characteristic of the syndrome of obstructive sleep apnea and is frequently accompanied by potentially life-threatening tachy- and bradyarrhythmias. Possible mechanism of production of these arrhythmias, the mode of action of tracheostomy and atropine, and the probable role of similar arrhythmias in the sudden infant death syndrome are discussed.

Apnea↗
PubMed1977

Propranolol for patients with mitral valve prolapse.

This study evaluates propranolol's effect on symptoms, arrhythmias, and exercise tolerance in 16 patients with mitral valve prolapse. Three patients (19 per cent) experienced symptomatic deterioration with propranolol therapy, seven (44 per cent) were unchanged, and six (37 per cent) noted an over-all symptomatic improvement, primarily due to a reduction in palpitation. Symptomatic improvement continues in these six patients an average of 12.5 months after beginning propranolol therapy. Treatment with propranolol alleviated chest pain in only two of eight patients and it did not improve the ability to perform treadmill exercise. Fatigue did not improve, and in three patients appeared for the first time during propranolol therapy. Premature ventricular contractions were reduced by at least 75 per cent in five of nin patients (56 per cent), and paroxysmal ventricular tachycardia was eliminated in three of four patients. We conclude that propranolol is not uniformly effective in patients with mitral vale prolapse. A trial of propranolol may be instituted fro patients with mitral valve prolapse who have severe symptoms and/or arrhythmias, but the drug should only be continued in those who demonstrate clinical and/or antiarrhythmic response.

Adult↗
PubMed1977

Characteristics of ventricular tachycardia in ambulatory patients.

This study analyzes 94 episodes of the ventricular tachycardia recorded in the ambulatory electrocardiograms of 23 patients with stable cardiac disease. The episodes were asymptomatic in 19 patients, and only one episode resulted in ventricular fibrillation. Eighty-five percent of the episodes occurred when the underlying heart rate was less than 100 beats/min, and 17 percent occurred during sleep. The rate of the ventricular tachycardia was between 120 and 180 beats/min in 78 percent of the episodes and showed a modest correlation with the underlying heart rate (r = 0.59, P less than 0.001). Only 14 of the 94 episodes were initiated by R on T premature ventricular contractions, and the mean prematurity index (+/- standard deviation) (R-R'/Q-T) for all episodes was 1.31 +/- 0.28. Episodes of ventricular tachycardia recorded during ambulatory electrocardiographic monitoring are usually self-limited and asymptomatic. They occur during ordinary nonexertional activity and are frequently initiated by late couples premature ventricular contractions.

Ambulatory Care↗
PubMed1977

Sudden death.

The alert physician can identify and probably alter the risk of sudden death for certain patients (see Table 5). It appears preferable to study the patient who has already been identified as having coronary artery disease because of clinical symptoms such as R/O MI, which has been shown to have a high risk for subsequent sudden death. In addition, the physician must be sensitive to the middle-aged man with multiple coronary artery disease risk factors who suddenly decides to have a routine check or develops nonspecific complaints. Once identified, patients can be educated to minimize delay time in seeking medical help with crescendo or prolonged angina. Ambulatory ECG monitoring for detection and characterization of ventricular arrhythmias, and exercise stress testing to detect severe ST depression, can facilitate an estimation of the patient's prognosis. A therapeutic plan, including attack on the patient's coronary artery disease risk factors, patient education, and specific medical or surgical therapies may alter the risk of sudden death. Once an infarction has occurred, rapid transport to a coronary care unit or monitoring facility, and administration of intramuscular lidocaine by medical or paramedical personnel when feasible, appear to lessen out-of-hospital mortality.

Angina Pectoris↗
PubMed1977

Successful retransplantation of the human heart.

Cardiac retransplantation has been performed in five patients at Stanford University Medical Center. Long-term survival and rehabilitation have been achieved in two cases. In the first case retransplantation was performed 57 days after the initial procedure because of persistent acute graft rejection. The second patient underwent retransplantation 27 months postoperatively because of documented accelerated graft atherosclerosis. The major indications for cardiac retransplantation consist of intractable acute rejection and late postoperative graft atherosclerosis. These complications should prompt consideration of cardiac retransplantation in carefully selected cases.

Adolescent↗
PubMed1976

The cardiovascular effects of lithium in man. A review of the literature.

The medical literature since 1900 has been reviewed to determine the nature of lithium's cardiovascular effects. In therapeutic doses, lithium produces reversible T wave flattening and inversion in the electrocardiogram: rarely, it may cause sinus node dysfunction or ventricular arrhythmias. Patients with lithium toxicity almost always present with neurologic signs and symptoms. "Hypotension and cardiovascular collapse," alleged cardiotoxic manifestations of lithium, invariably follow days of coma. Given the possible cardiotoxic effect other psychopharmacologic agents and the hazards of withholding effective therapy in mania, it is concluded that lithium may be used safely in patients with cardiac disease if the dose is adjusted to the rate of lithium excretion and if serum levels of lithium are followed carefully. When used in patients with cardiac arrhythmias, frequent electrocardiographic monitoring is advised.

Adult↗
PubMed1976

Infections after cardiac transplantation: relation to rejection therapy.

We have analyzed the relation of the treatment of 76 acute graft rejection episodes in 45 late postoperative cardiac transplant patients to the 56 infections occurring in these patients. Intensification of immunosuppressive therapy for acute rejection greatly increased the occurrence of infection from a control incidence of 1.3 infections per 1000 patient-days to a posttreatment incidence of 3.6. Two modes of treatment, increased oral prednisone and high-dose methylprednisolone plus antithymocyte globulin, were further analyzed. Actuarial analysis of infections after these two treatment modes showed that the treatment-related increase in infection was nearly exclusively due to the latter form of therapy. Invasive cardiac procedures did not appear to be causally related to infections in these immunocompromised patients.

Antilymphocyte Serum↗
PubMed1976

Does cardiac transplantation prolong life and improve its quality? An updated report.

The current status of the human cardiac transplant experience at Stanford University Medical Center is presented in order to reassess its role in the treatment of end-stage cardiac disease. Of 109 patients undergoing transplantation at Stanford between January 1968 and August 1976, 44 were still alive as of August 1, 1976. The overall 1- and 2-year survival rates for the series are 52% and 43%, respectively. Sixty-nine patients have survived more than 3 months, and their overall 1- and 2-year survival rates are 80% and 66%, respectively. Of the 3-month survivors, 62 (90%) returned to functional Class I New York Heart Association cardiac status and most of these returned to their pre-illness activities. Of 40 patients selected for transplantation for whom a donor did not become available, 38 were dead in less than 6 months. Complications related to immunosuppression with steroids are currently the major barrier to longer survival and improved rehabilitation postransplantation. On the basis of these data we conclude that cardiac transplantation not only prolongs survival, but can return carefully selected recipients to an active life.

Adolescent↗