Biomedical subjects

M Linzer

Publications and source records attributed to M Linzer.

At least 19 recordsLinked to original sources

PubMed1992

Usefulness of clinical characteristics in predicting the outcome of electrophysiologic studies in unexplained syncope.

Guidelines for the use of electrophysiologic studies in syncope have not yet been formulated. To confirm the sensitivity and specificity of a previously derived model to predict the results of electrophysiologic testing in syncope, the importance of 6 clinical predictors was assessed in a new data set of 141 consecutive patients with unexplained syncope who were referred for electrophysiologic studies. The 6 predictors were: organic heart disease; premature ventricular beats, sinus bradycardia, first-degree heart block and bundle branch block by electrocardiogram; and nonsustained ventricular tachycardia by Holter monitor. Organic heart disease and nonsustained ventricular tachycardia by Holter monitoring were highly sensitive for serious ventricular tachyarrhythmias at electrophysiologic study (sensitivity 100%), whereas sinus bradycardia, first-degree heart block or bundle branch block by electrocardiogram were sensitive for bradyarrhythmic outcomes (sensitivity 79%). Because these variables are so sensitive for serious outcomes of electrophysiologic testing in syncope, invasive studies in patients without these clinical predictors are likely to be of very low diagnostic yield.

Adult↗

PubMed1992

Medically unexplained syncope: relationship to psychiatric illness.

The purpose of this article is to review the literature and present new data concerning the relationship between psychiatric disorders and unexplained syncope. Several case series are presented of patients with syncope in whom psychiatric structured interviews were undertaken, tilt-table (physiologic) testing was performed, and health-related quality of life was measured. Patients seen in a syncope specialty clinic underwent structured psychiatric interviews in addition to in-depth medical evaluations. Tilt-table testing was performed on a separate series of patients to determine susceptibility to syncope during the orthostatic challenge of head-up tilt; in some cases, tilt studies included simultaneous electroencephalographic (EEG) monitoring and cerebral blood flow measurements. Formal functional status assessment was carried out using the Sickness Impact Profile, the Symptom Check List 90, and the Medical Outcomes Study Short-Form 36. Psychiatric disorders (in particular, panic disorders and major depression) were a common cause of syncope (24-31% of syncope patients). Tilt table studies showed several physiologic profiles in syncope: (a) a typical vasovagal (hypotension-bradycardia) response, (b) a "psychosomatic" response (fainting with normal vital signs), and (c) a gradual decline in blood pressure (dysautonomic response). EEG and cerebral blood flow measurements in three patients with the psychosomatic response to tilt were normal during fainting. Functional status measurements showed serious impairment in two series of syncope patients. Conclusions were as follows: (a) Psychiatric disorders are common in syncope. (b) Tilt-table methodology may elucidate underlying mechanisms of syncope in these subjects. (c) Syncope can seriously disrupt a patient's life and result in important psychosocial sequelae. (d) There is an intimate relationship between unexplained syncope and psychiatric illness, mandating a combined medical and psychiatric approach to such patients.

Humans↗

PubMed1992

Syncope in young adults: evidence for a combined medical and psychiatric approach.

To determine the principal causes and effects of syncope in young adults, we prospectively evaluated 197 consecutive patients referred to a Syncope Specialty Clinic, comparing young (age 16-39 years, n = 71), middle-aged (age 40-65 years, n = 70) and elderly (greater than age 65 years, n = 56) patients. Psychiatric aetiologies were significantly more common in young patients (39% vs. 20% in middle-aged, and 3.6% in the elderly; P less than 0.001), while cardiac aetiologies were rare in the young (2.8% vs. 12% in the middle-aged, and 16% in the elderly; P less than 0.04). These differences were still significant after controlling for gender. Because psychiatric causes are so common in young patients, we evaluated hyperventilation as a bedside test for syncope patients and found it to have a positive predictive value of 59% for psychiatric causes of syncope. Syncope interfered with daily activities in 62% of young patients, and resulted in anxiety or depression in 70% of the young (no difference when compared with other age groups). Thus syncope in young adults can be a disabling medical condition requiring a unique medical and psychological approach to diagnosis and treatment.

Adolescent↗

PubMed1992

Critical carotid and vertebral arterial occlusive disease and cough syncope.

BACKGROUND AND PURPOSE: Cough syncope typically occurs in patients with known chronic lung disease. The mechanism usually involves a combination of decreased venous return, increased cerebrospinal fluid pressure, and secondary hypocapnia, all resulting in cerebral arterial vasoconstriction. Cough syncope has not in the past been associated with occlusive cerebrovascular disease. CASE DESCRIPTION: We describe a 50-year-old man with a 6-month history of episodes of loss of consciousness during paroxysms of coughing. Physical examination showed asymmetrical upper extremity blood pressures and carotid and subclavian artery bruits. Pulmonary function studies were normal. Ultrasound and angiography showed total occlusion of the left common carotid artery, right internal carotid artery, and right vertebral artery; tight stenosis of the right subclavian artery; and a hypoplastic left vertebral artery. The patient had a left subclavian-to-left common carotid artery bypass and has had no syncope since that time. CONCLUSIONS: To our knowledge, this is the first reported case of cough syncope and severe cerebrovascular disease in which surgery led to amelioration of symptoms. Cerebrovascular occlusive disease may contribute to cough syncope.

Aortography↗

PubMed1991

Medical student interest in internal medicine. Initial report of the Society of General Internal Medicine Interest Group Survey on Factors Influencing Career Choice in Internal Medicine.

OBJECTIVE: To determine the factors that attract students toward and push students away from a career in internal medicine. DESIGN: National survey of senior U.S. medical students using a stratified random cluster sampling of medical schools. PARTICIPANTS: The survey included 1650 U.S. senior students from 16 medical schools, of whom 1244 (76%) responded. MEASUREMENTS AND MAIN RESULTS: A survey instrument was developed and pilot tested at 17 medical schools. Twenty-four percent of the respondents to the final survey chose a career in general internal medicine (9%) or subspecialty internal medicine (15%). A career in internal medicine had been "seriously considered" by 608 respondents (50%) who finally chose a career other than internal medicine (the "switchers"). Compared with other specialties, internal medicine was perceived as being more stressful to residents, more demanding of time and workload as a career and a residency, and as an easier residency to enter. Internal medicine was also seen as providing less satisfaction for residents, having lower income potential, and allowing less leisure time. For the 608 switchers, the most important influences leading to their decision to switch were the type of patient seen in internal medicine (for example, chronically ill, alcohol and drug abusing patients) as well as dissatisfaction and stress among internal medicine residents. Factor analysis showed that three factors, "intellectual challenge of internal medicine," "primary care interests," and "the medicine clerkship" attracted students toward internal medicine, whereas three others, "taking care of chronically ill patients," "level of satisfaction among internists and medical residents," and "workload and stress" pushed students away from internal medicine. Factors pushing students away from internal medicine were significantly more negative with regard to a career in general as opposed to subspecialty internal medicine (P less than 0.001). CONCLUSION: Medical students have serious reservations about internal medicine as a career choice. Perceptions about the medical residency, the patients they expect to see, and the dissatisfaction among residents and internists are foremost in their thinking. Changes to improve the attractiveness of internal medicine should address these adverse perceptions while building on the positive influences identified by the respondents.

Career Choice↗

PubMed1991

Syncope: 1991.

Explore the source record for details and available documents.

Adult↗

PubMed1991

Impairment of physical and psychosocial function in recurrent syncope.

Physical and psychosocial function have rarely been assessed in syncope. We used two valid and reliable measures of health status, the Sickness Impact Profile (SIP) and the Symptom Checklist 90 (SCL-90-R), to assess functional impairment in 62 patients with recurrent syncope seen in a syncope specialty clinic. Mean total SIP scores were markedly elevated at 17 (SD = 14), indicating a level of impairment similar to severe rheumatoid arthritis and chronic low back pain. SIP psychosocial scores were significantly greater than SIP physical scores (20 vs 11, p less than 0.0001). SCL-90-R scores were also high, comparable to those of psychiatric inpatients. Somatization, anxiety and depression dimensions of the SCL-90-R were particularly elevated. SCL-90-R subscale scores were highly correlated with SIP psychosocial scores (all r greater than 0.4, and p less than 0.001). Neither age nor number of comorbid diseases correlated with measures of psychosocial function, suggesting that syncope itself causes psychosocial impairment. Although this was a referral population, these data suggest that function can be seriously impaired by syncope, that the degree of impairment is similar to that reported in other chronic diseases, and that syncope leads to significantly greater psychosocial than physical impairment.

Activities of Daily Living↗

PubMed1991

Cardiovascular and catecholamine responses to head-up tilt in the diagnosis of recurrent unexplained syncope in elderly patients.

To increase understanding of the mechanisms causing syncope in patients over the age of 60, hemodynamic and hormonal responses to 60 minutes of 60 degree head-up tilt were examined in 10 patients with recurrent syncope of unknown origin and five controls with no history of syncope. Nine of 10 patients and all five controls experienced orthostatic intolerance on the tilt table. Syncope or pre-syncope occurred later in controls than in those syncope patients who had exact reproduction of their clinical symptoms (median time 52 versus 22 minutes, P = 0.05). Three different mechanisms of orthostatic intolerance were identified in the 14 subjects: (1) vasovagal syncope, n = 9 (sudden hypotension +/- bradycardia); (2) dysautonomic syncope, n = 3 (immediate and gradual parallel declines in both systolic and diastolic pressures with blunted increase in heart rate); (3) psychogenic or vestibular reaction, n = 2 (orthostatic intolerance without hemodynamic changes). Vasovagal syncope patients showed a significant increase in plasma norepinephrine from baseline to maximum level during tilt (100 +/- 39% increase, P = 0.03) and a subsequent decrease at the time of syncope (30 +/- 5% decrease, P = 0.01), while plasma epinephrine increased markedly from baseline to the time of syncope (827 +/- 154% increase, P = 0.0003). Dysautonomic syncope patients had lower supine levels of norepinephrine compared to vasovagal syncope patients (182 +/- 30 versus 614 +/- 146 pg/mL, P = 0.008) and no significant change in norepinephrine over time; epinephrine levels increased significantly less than in vasovagal patients (net change 38 +/- 8 versus 189 +/- 56 pg/mL, P = 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1991

Clinical significance of a dizziness history in medical patients with syncope.

To determine the implications of dizziness as a symptom in patients with syncope, we analyzed responses to a standardized battery of questions about dizziness in 121 consecutive patients referred for evaluation of syncope. Associations were sought between final diagnosis (dependent variable) and clinical predictor variables. Dizziness was found in 70% of the patients with syncope. Dizzy patients were younger (mean ages, 47 vs 56 years, respectively), more often female (75% vs 42%), and more likely to be assigned a psychiatric diagnosis. Multivariable logistic regression analysis identified young age and rotatory dizziness (vertigo) to be associated with a psychiatric diagnosis. Dizziness and syncope frequently coexist and in many cases may represent the same pathophysiologic process. A careful dizziness history may guide the initial evaluation of syncope patients in clinical practice.

Adolescent↗

PubMed1990

Incremental diagnostic yield of loop electrocardiographic recorders in unexplained syncope.

The Holter monitor, the most frequently used diagnostic test in patients with syncope, is nondiagnostic in over 90% of cases. This study sought to determine the impact of a new noninvasive device, the cardiac loop electrocardiographic (ECG) recorder, after Holter monitoring in 57 patients with unexplained syncope. All patients underwent a standardized evaluation protocol and were the monitor for up to 1 month. In 14 patients, loop recording definitively determined whether an arrhythmia was the cause of symptoms (diagnostic yield 25%; 95% confidence intervals 14 to 38%). Diagnoses included unsuspected ventricular tachycardia (1 patient), high grade atrioventricular block (2 patients), supraventricular tachycardia (1 patient), asystole or junctional bradycardia from neurally mediated syncope (3 patients) and normal cardiac rhythms (the remaining 7 patients). Follow-up of all patients diagnosed as having nonarrhythmic syncope by loop recording showed that none of these patients died suddenly. Cardiac loop ECG recording is an important new diagnostic test in patients with syncope unexplained by Holter monitoring.

Arrhythmias, Cardiac↗

PubMed1990

Syncope: current diagnostic evaluation and management.

OBJECTIVE: To provide a comprehensive review of the causes, current diagnostic evaluation, and treatment of syncope. DATA IDENTIFICATION: New data and knowledge in this evolving field were critically analyzed by doing a MEDLINE search on syncope supplemented by selective review of English language literature citations in the Index Medicus before 1980. STUDY SELECTION: We reviewed approximately 200 published articles on syncope and closely related topics as well as using our own clinical experience. We selected articles if they addressed the pathophysiology of syncope, classification and causes, differential diagnosis, noninvasive and invasive evaluation, and current therapy. RESULTS OF DATA SYNTHESIS: Syncope is a common clinical problem, occurring in 30% to 50% of the adult population. The prognosis for syncope depends on its cause. Cardiac syncope has the worst prognosis and therefore mandates thorough evaluation and prompt treatment. Diagnostic evaluation is made difficult by the transient nature of the episodes and the many causes. Noninvasive testing reveals the cause of syncope in approximately 50% of cases. More extensive evaluation, including invasive electrophysiologic studies, has assumed a larger role in defining the cause of syncope in selected patients with structural heart disease in whom a noninvasive evaluation has been nondiagnostic. Recently tilt-table studies have been proposed as a clinically useful noninvasive test for vagally mediated syncope. CONCLUSIONS: A rational stepwise diagnostic and therapeutic approach to patients with syncope can be developed by initially doing a careful history and physical examination followed by a noninvasive evaluation and selective use of additional, more specialized or invasive tests. Future research should focus on defining the validity and utility of current diagnostic testing in syncope and on exploring further the pathophysiology of patients with recurrent, unexplained syncope.

Cardiovascular Diseases↗

PubMed1990

Cardiac loop ECG recording: a new noninvasive diagnostic test in recurrent syncope.

The most crucial step in diagnosing syncope is determining whether or not an arrhythmia is the cause. A new recording device, the continuous cardiac loop ECG recorder, affords prolonged ambulatory monitoring and can capture the rhythm at the time of syncope. To determine the impact of cardiac loop ECG recorders in diagnosing syncope, we reviewed the records of the first 48 patients referred for cardiac loop recording because of unexplained syncope or presyncope. Previous cardiac studies were nondiagnostic in all patients. In 36% of these patients, loop recording definitively determined whether an arrhythmia was the cause of symptoms. Median duration of monitoring was 28 days, with an average charge of $180 per month. Cardiac loop ECG recording is a convenient, safe, inexpensive, and potentially highly effective means of diagnosing unexplained syncope.

Adolescent↗

PubMed1990

Syncope and presyncope associated with probable adverse drug reactions.

The purpose of this study was to determine whether syncope and presyncope were associated with drug therapy in 70 patients referred to a tertiary care ambulatory clinic. Drug use information was obtained, validated, and classified by its potential to cause syncope and presyncope. Utilizing a standardized adverse drug reaction algorithm, nine (13%) of the 70 patients were rated as having probable drug-induced syncope and presyncope events. Overall, 12 medications were implicated. Patients with probable adverse drug reactions were older, and taking more medications, or taking an antihypertensive. Seven of the nine patients with probable adverse drug reactions were previously classified as having syncope of unknown origin after their initial clinic evaluation. Syncope and presyncope are commonly associated with adverse drug reactions, especially in the elderly and those taking multiple medications.

Accidental Falls↗

PubMed1990

Psychiatric syncope: a new look at an old disease.

Psychiatric disorders in patients with unexplained syncope or presyncope have received little attention in the recent medical literature. Seventy-two patients with unexplained syncope and presyncope referred to the Duke Syncope Clinic received a standardized evaluation. Symptoms appeared to be explained by a psychiatric diagnosis in 17 (24%) patients (panic disorder in 13%, and major depression in 11%). These patients were younger than other patients with syncope and presyncope (p less than .001) and had more disability due to their syncope and presyncope (p less than .01). They also had more frequent episodes of syncope (p less than .005) and more symptoms as a part of their prodrome (p less than .0001). Treatment aimed at the psychiatric diagnosis resulted in a remission from syncopal or presyncopal symptoms in 90% of patients who complied with therapy. The authors conclude that psychiatric disorders are common in patients with syncope and presyncope, that certain characteristics of the patient and prodrome may alert physicians to a psychiatric diagnosis, and that directed treatment may result in relief from symptoms.

Anxiety Disorders↗

PubMed1979