Search PubMed⌕ Search

Biomedical subjects

R G Hart

Publications and source records attributed to R G Hart.

At least 19 recordsLinked to original sources
PubMed1992

Antiarrhythmic drug therapy and cardiac mortality in atrial fibrillation. The Stroke Prevention in Atrial Fibrillation Investigators.

BACKGROUND AND OBJECTIVES: The relation between cardiac mortality and antiarrhythmic drug administration has not been fully determined. This relation was analyzed in 1,330 patients enrolled in the Stroke Prevention in Atrial Fibrillation Study, a randomized clinical trial comparing warfarin, aspirin and placebo for the prevention of ischemic stroke or systemic embolism in patients with nonvalvular atrial fibrillation. METHODS: Patients who received antiarrhythmic drug therapy for atrial fibrillation in this study were compared with patients not receiving antiarrhythmic agents. The relative risk of cardiac mortality, including arrhythmic death, in patients receiving antiarrhythmic drug therapy was determined and adjusted for other cardiac risk factors. RESULTS: In patients receiving antiarrhythmic drug therapy, cardiac mortality was increased 2.5-fold (p = 0.006, 95% confidence interval [CI] 1.3 to 4.9) and arrhythmic death was increased 2.6-fold (p = 0.02, 95% CI 1.2 to 5.6). Among patients with a history of congestive heart failure, those given antiarrhythmic medications had a relative risk of cardiac death of 4.7 (p less than 0.001, 95% CI 1.9 to 11.6) compared with that of patients not so treated; the relative risk of arrhythmic death in the treated group was 3.7 (p = 0.01, 95% CI 1.3 to 10.4). Patients without a history of congestive heart failure had no increased risk of cardiac mortality (relative risk 0.70, 95% CI 0.2 to 3.1) during antiarrhythmic drug therapy. After exclusion of 23 patients with documented ventricular arrhythmias and adjustment for other variables predictive of cardiac death, patients receiving antiarrhythmic drugs were not at increased risk of cardiac death or arrhythmic death. However, in patients with a history of heart failure who received antiarrhythmic drug therapy, the relative risk of cardiac death was 3.3 (p = 0.05, 95% CI 0.99 to 11.1) and that of arrhythmic death was 5.8 (p = 0.009, 95% CI 1.5 to 21.7) compared with the risk in patients not taking antiarrhythmic medications. CONCLUSIONS: Although antiarrhythmic drug therapy was not randomly determined in this trial, the data suggest that in patients with atrial fibrillation and a history of congestive heart failure, the risk of such therapy may outweigh the potential benefit of maintaining sinus rhythm.

Anti-Arrhythmia Agents↗
PubMed1991

Antithrombotic therapy in cerebrovascular disease.

For more than two decades, anticoagulant and antiplatelet agents have been used routinely to prevent and treat ischemic stroke. Although recent clinical trials have shown that such treatment can be helpful in certain cases, antithrombotic therapy currently remains of unproven benefit in many clinical settings of cerebrovascular disease. Although the absence of data confirming clinical efficacy has generated uncertainty and hesitancy in some clinicians, the lingering conviction that antithrombotic therapy is efficacious has led others to continue a policy of routine and active therapeutic intervention. A critical analysis of the literature on antithrombotic therapy and cerebrovascular disease suggests that many acceptable management options lie between the extremes of therapeutic nihilism and "routine" intervention.

Anticoagulants↗
PubMed1991

Tension pneumothorax associated with hyperbaric oxygen therapy.

The authors present three patients who developed a tension pneumothorax while receiving emergent hyperbaric oxygen therapy for acute carbon monoxide poisoning. Each patient was intubated and received closed chest compressions for cardiac arrest prior to hyperbaric oxygenation. Despite the apparent absence of pneumothorax prior to hyperbaric therapy, tension pneumothorax was detected soon after decompression. These cases illustrate the need for vigilance in detecting and addressing pneumothorax prior to hyperbaric decompression in obtunded patients. Serial physical examinations, arterial blood gas determinations, properly positioned chest radiographs, and a high index of suspicion for pneumothorax in the setting of emergent hyperbaric therapy are recommended.

Adolescent↗
PubMed1991

Neurologic complications of infective endocarditis.

Neurologic syndromes often complicate the management of infective endocarditis (IE). We retrospectively reviewed 166 episodes of native valve endocarditis to assess the occurrence and implications of nonfocal encephalopathy, meningitis, salient headache, back pain, and brain abscess. Neurologic complications occurred in 35% (58/166) of patients: 41% (54/133) of mitral or aortic valve IE and 12% (4/33) of tricuspid valve IE. Of 133 cases of mitral or aortic valve IE, encephalopathy occurred in 14%, meningitis in 5%, and salient headache in 3%. All neurologic complications occurred more often with Staphylococcus aureus infection (67%) than with viridans streptococci (22%), including encephalopathy (22% versus 7%), meningitis (17% versus 0%), stroke (39% versus 16%), and death (39% versus 9%). Encephalopathy was associated with virulent organisms, increased patient age, and uncontrolled infection. Clinical, radiologic, and neuropathologic data all suggest that infective microemboli are often etiologic in IE-related encephalopathy. There were no macroscopic brain abscesses clinically identified. Meningitis occurred only with virulent organisms. While many clinical aspects of IE have changed in recent years, the frequency and gravity of neurologic complications have not.

Aortic Valve↗
PubMed1991

Cardiogenic stroke in the elderly.

Cardiogenic stroke accounts for 15-20% of all ischemic strokes and for more than double than number in the very elderly. In this article, available data regarding cardiogenic embolism, its prevention and management in the elderly are reviewed in addition to the epidemiology, diagnosis, and major sources of cardiac emboli, and nonrheumatic atrial fibrillation.

Aged↗
PubMed1990

Acute autonomic neuropathy. Two cases and a clinical review.

Acute autonomic neuropathy is an uncommon syndrome, usually affecting healthy young people. Presentation is often dramatic and initial misdiagnosis is common. We describe two young women with acute autonomic neuropathy who presented with gastrointestinal involvement heralding widespread dysautonomia and review 26 additional cases of acute autonomic neuropathy from the English language literature. Acute autonomic neuropathy can be primarily cholinergic without orthostatic hypotension (26%) or pandysautonomic (74%) involving sympathetic adrenergic functions. Onset has been temporally related to viral syndromes in 20% of cases, with autonomic deficits usually evolving over 1 to 3 weeks. Gastroparesis (69%) and syncope (12%) are frequent presenting complaints. Spinal fluid protein levels are often (75%) elevated in pandysautonomic subtypes. Prolonged and incomplete recovery is the rule (60%), with persistent gastroparesis and orthostatic hypotension. Other specific diseases that occasionally mimic acute autonomic neuropathy include botulism, porphyria, amyloidosis, and paracarcinomatous neuropathies. Acute autonomic neuropathy shares several clinical features with acute idiopathic polyneuropathy (Guillain-Barré syndrome), suggesting an immune-mediated pathogenesis.

Acute Disease↗
PubMed1990

Stroke in infective endocarditis.

We reviewed 212 consecutive episodes of infective endocarditis in 203 patients at six hospitals between 1978 and 1986 and found that 21% were complicated by stroke. Of 133 episodes involving native mitral and/or aortic valves, brain ischemia occurred in 19%, brain hemorrhage in 7%, and non-central nervous system emboli in 11%; vegetations were identified in 56% of 113 adequate echocardiograms and did not correlate with risk of embolism. In native-valve endocarditis, most (74%) ischemic strokes had occurred by the time of presentation and an additional 13% occurred less than or equal to 48 hours after diagnosis; the incidence of brain ischemia was 13% on presentation, 3% during the first 48 hours of hospitalization, and 2%-5% during the remainder of the acute course. Stroke recurred at a rate of 0.5%/day, often heralding relapse/uncontrolled infection. Only 9% of ischemic infarcts were large (all in patients with Staphylococcus aureus infection), while 8% were small and subcortical. Brain hemorrhage occurred primarily at the time of presentation, particularly in intravenous drug abusers, and was associated with uncontrolled S. aureus infection with pyogenic arteritis. Ischemic and hemorrhagic stroke continue to be frequent and important in patients with infective endocarditis and are clustered during uncontrolled infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Prosthetic valve endocarditis 1976-1987. Antibiotics, anticoagulation, and stroke.

We retrospectively reviewed the clinical characteristics and outcomes of 61 patients with 62 episodes of prosthetic valve endocarditis, paying particular attention to neurologic complications (stroke). Atypical features of the group included a benign outcome of early postoperative infection (18% mortality) and a high stroke morbidity and mortality rate with Staphylococcus epidermidis infections. Eleven patients (18%) suffered an embolic stroke, most less than or equal to 3 days after diagnosis and before the initiation of antimicrobial therapy; the rate of embolic stroke recurrence was low (9%). The risk of embolic stroke was lower with bioprosthetic than with mechanical valves. No protective effect of anticoagulation therapy with warfarin was observed. Six patients (8%) suffered brain hemorrhage due to septic arteritis, brain infarction, or undetermined causes; no specific risk of hemorrhagic stroke was evident with anticoagulation therapy. Antibiotic treatment appears to be more important than anticoagulation to prevent neurologic complications in patients with prosthetic valve endocarditis.

Anti-Bacterial Agents↗
PubMed1990

Hematologic disorders and ischemic stroke. A selective review.

More than a dozen primary hematologic disorders have been associated with ischemic stroke. Inherited deficiencies of antithrombin III, protein C, and protein S have been linked with stroke in case reports; optimal screening requires functional as well as antigenic assays. Antiphospholipid antibodies and lupus anticoagulants are the most frequently identified acquired states associated with ischemic stroke. Polycythemia vera, sickle cell anemia, sickle-C disease, and essential thrombocythemia are the major disorders of formed blood elements causing stroke. Special, step-wise screening for occult prothrombotic entities in stroke patients is recommended for young persons with stroke of uncertain cause, for those with prior venous thrombosis, for those with a family history of unusual thrombosis, and for those with no other explanation for recurrent stroke. Acquired, perhaps transient, abnormalities of platelets, coagulation inhibition, and fibrinolysis may contribute importantly to brain ischemia in synergy with other mechanisms, but at present these remain ill-defined. The contribution of prothrombotic diatheses to stroke is probably underrecognized and warrants further investigation.

Autoimmune Diseases↗
PubMed1990

Antiphospholipid antibodies and cerebral ischemia in young people.

The importance of a prothrombotic state as a cause of ischemic stroke in young adults is ill defined. We examined 46 unselected patients under age 50 years with cerebral ischemia for anticardiolipin antibody (aCL) and lupus anticoagulants (LA), over a 3-year-period. Age- and sex-matched patients with other neurologic diseases served as a noncerebral ischemia comparison group to test whether (1) stroke/transient ischemic attacks (TIA) in young people is associated with aCL and/or LA, and (2) their presence is specific to cerebral ischemia. In the stroke/TIA group, 21 patients had aCL or LA and 25 had neither, whereas in the control group, 2 patients had aCL and 24 had neither. Equal numbers of stroke/TIA patients with and without antiphospholipid antibodies (aPL) had other stroke risk factors. Patients with aPL and cerebral ischemia, however, had a more frequent history of multiple events than those without them. These antibodies occur with undue frequency in young patients with stroke/TIA and are not associated with a concurrent diagnosis of systemic lupus in most cases. A coexistent aPL-associated prothrombotic state may be a key determinant of whether patients with atherosclerosis, mitral valve prolapse, or other structural lesions experience recurrent ischemia.

Adult↗
PubMed1990

Epidemiologic features of asymptomatic cerebral infarction in patients with nonvalvular atrial fibrillation.

We performed unenhanced computed tomographic scans on 141 asymptomatic patients with nonvalvular atrial fibrillation. Thirty-six patients (26%) had hypodense areas consistent with cerebral infarction. The majority of these were small deep infarcts, seen in 29 patients (21%), but 13 patients (9%) had cortical or large deep infarctions. Twelve patients had more than one infarct on computed tomographic scan. Increasing age and increased left atrial diameter were the only clinical features associated with asymptomatic infarction. Patients older than 65 years with a left atrial diameter greater than 5.0 cm (n = 23) had a 52% prevalence of asymptomatic infarction. Patients younger than 65 years with a left atrial diameter less than 5.0 cm (n = 38) had an 11% prevalence of silent infarction. Patients with only one of these risk factors (n = 72) had a 24% prevalence of silent infarction. Infarction was more common in those with chronic (34%) as opposed to intermittent (22%) nonvalvular atrial fibrillation, but this difference was not significant. Hypertension, diabetes, duration of atrial fibrillation, congestive heart failure, history of myocardial infarction, and echocardiographic evidence of left ventricular dysfunction were not associated with asymptomatic infarction. A history of hypertension was present in only 35% of our patients with small-deep asymptomatic infarction, similar to the percentage in patients without stroke. Asymptomatic cerebral infarction is common in nonvalvular atrial fibrillation. The association with enlarged left atria and the lack of correlation with major cerebrovascular risk factors suggests a cardioembolic mechanism. Further study is needed to determine the functional and prognostic significance of these strokes.

Aged↗
PubMed1989

Stroke in the People's Republic of China.

Recent epidemiologic studies confirm that stroke is the most frequent cause of death in the People's Republic of China, with an incidence (219/100,000 people) more than fivefold that of myocardial infarction. Intracerebral hemorrhage causes about one third of all strokes, nearly three times the frequency in North American stroke registries. A marked regional variation in stroke incidence exists, with a threefold higher stroke incidence in northern than in southern Chinese cities, suggesting important environmental or dietary influences. Stroke treatment often involves a combination of modern and traditional herbal medicine; the latter may modify platelet aggregation and blood viscosity. Stroke, particularly intracerebral hemorrhage, is the most frequent and important vascular disorder in the People's Republic of China.

Cerebral Hemorrhage↗
PubMed1989

Arrogance revisited.

Explore the source record for details and available documents.

Clinical Trials as Topic↗