Mark Linzer

The difficult patient: prevalence, psychopathology, and functional impairment.

OBJECTIVE: To determine the proportion of primary care patients who are experienced by their physicians as “difficult,” and to assess the association of difficulty with physical and mental disorders, functional impairment, health care utilization, and satisfaction with medical care.DESIGN: Survey.SETTING: Four primary care clinics.PATIENTS: Six-hundred twenty-seven adult patients.MEASUREMENTS: Physician perception of difficulty (Difficult Doctor-Patient Relationship Questionnaire), mental disorders and symptoms (Primary Care Evaluation of Mental Disorders, [PRIME-MD]), functional status (Medical Outcomes Study Short-Form Health Survey [SF-20]), utilization of and satisfaction with medical care by patient self-report.RESULTS: Physicians rated 96 (15%) of their 627 patients as difficult (site range 11–20%). Difficult patients were much more likely than not-difficult patients to have a mental disorder (67% vs 25%, p<.0001). Six psychiatric disorders had particularly strong associations with difficulty: multisomatoform disorder (odds ratio [OR]=12.3, 95% confidence interval [CI]=5.9–25.8), panic disorder (OR=6.9, 95% CI=2.6–18.1), dysthymia (OR=4.2, 95% CI=2.0–8.7), generalized anxiety (OR=3.4, 95% CI=1.7–7.1), major depressive disorder (OR=3.0, 95% CI=1.8–5.3), and probable alcohol abuse or dependence (OR=2.6, 95% CI=1.01–6.7). Compared with not-difficult patients, difficult patients had more functional impairment, higher health care utilization, and lower satisfaction with care, whereas demographic characteristics and physical illnesses were not associated with difficulty. The presence of mental disorders accounted for a substantial proportion of the excess functional impairment and dissatisfaction in difficult patients.CONCLUSIONS: Difficult patients are prevalent in primary care settings and have more psychiatric disorders, functional impairment, health care utilization, and dissatisfaction with care. Future studies are needed to determine whether improved diagnosis and management of mental disorders in difficult patients could diminish their excess disability, health care costs, and dissatisfaction with medical care, as well as the physicians’ experience of difficulty.

CLINICAL GUIDELINE: Diagnosing Syncope: Part 1: Value of History, Physical Examination, and Electrocardiography

Syncope is a transient loss of consciousness that is accompanied by loss of postural tone. It is common [1] and can be dangerous [2], disabling [3], and difficult to diagnose [4]. Thousands of dollars can be spent evaluating a patient with syncope, only to result in a series of negative test results and a patient who continues to faint. Because the range of prognoses in syncope is wide, the physicians principal initial task is to distinguish between benign and life-threatening causes of syncope. We intend primarily to help clinicians maximize the diagnostic yield in the workup of syncope. Our secondary purpose is to summarize the literature that will aid clinicians in assessing risk to enable them to target hospitalization and invasive testing for the patient with syncope who is at high risk for an adverse outcome. The questions addressed by this two-part study are 1) Which diagnostic techniques are the most valuable for patients with syncope? 2) How can the clinical history help focus the workup for patients with syncope? and 3) When should patients with syncope be hospitalized? Methods We used the MEDLINE database to identify articles related to syncope and diagnostic testing. References that evaluated the diagnostic test in near syncope and dizziness were included if they also used the test in patients with syncope. When a medical subject heading did not identify a sufficient number of references about a particular diagnostic test (such as neurovascular testing or carotid Doppler ultrasonography), keyword searches (using such terms as transcranial Doppler) were done. To be included in the review, articles had to be published in the English language between 1980 and 1995. The studies had to be randomized trials, observational studies, cohort studies, or case series of more than 10 patients (review articles and case reports were excluded); had to focus on or include patients with syncope; and had to examine only patients 18 years of age or older (except for tilt-table studies, which often included adult and pediatric cases in the same articles). Articles that were candidates for review were evaluated in detail by one of the authors. Articles that met the selection criteria were used to prepare summary tables or paragraphs. Comparisons between groups (for example, the proportion of patients with and without heart disease who had tachyarrhythmias diagnosed by electrophysiologic testing) were made using the Fisher exact test. Selected national experts in cardiology and neurology were asked to review the findings in their area of expertise. The opinions of these experts were incorporated into the recommendations. Limitations of the Literature on Syncope In syncope, there is no diagnostic gold standard against which other diagnostic tests may be measured; thus, sensitivity and specificity may not be easily calculated. Moreover, the presence of a disease, such as coronary disease, in a patient who has fainted does not prove that the disease caused the syncope. Syncope is, at its core, a symptom and not a disease. Therefore, this review is not organized around a technology or a disease entity but focuses on the physiologic states that lead to a sudden, transient loss of consciousness. The literature that discusses syncope predominantly comprises case series or cohort studies based on referrals to tertiary care centers. We classified studies into three types: population-based studies (including unselected patients from the general population who were hospitalized or seen in emergency departments and other outpatient settings), referral-based studies (including patients referred to specialized centers for syncope workups), and small case series. To our knowledge, no randomized trials of the diagnostic workup or management strategies for patients with syncope have been done. A summary of the types of studies conducted in patients with syncope (Table 1) shows that most have been referral studies or case series. Table 1. Sample Characteristics of Studies of Diagnostic Tests and Syncope Definitions Organic Heart Disease Whenever possible, our definition of organic heart disease included coronary artery disease, congestive heart failure, valvular heart disease, cardiomyopathy, and congenital heart disease. Because conduction system disease is a separate predictor of the need for special diagnostic testing, it was kept apart except where indicated. Patients who had a history and physical examination that were negative for cardiovascular symptoms or signs and a normal electrocardiogram were considered to have normal hearts; however, we recognize that some investigators think that echocardiography should be done before patients are declared free of organic heart disease. Diagnostic Yield For most tests, the diagnostic yield reflects the number of patients with positive diagnostic test results divided by the number of tested patients. For Holter and loop monitoring, the numerator includes the sum of the true-positive test results (arrhythmias during fainting) plus the true-negative test results (normal rhythm during symptoms). This expanded definition reflects the prognostic importance of a negative result on electrocardiography during syncope. For certain tests, the absolute value of the diagnostic yield may not be as important as the ability of the test to exclude a serious diagnosis (for example, intracardiac electrophysiologic studies may be of considerable benefit when they exclude ventricular tachycardia in a patient in whom that diagnosis was strongly considered). Data Synthesis Differential Diagnosis The first category of syncope is neurally mediated syncope, which results from reflex mechanisms that are associated with inappropriate vasodilatation, bradycardia, or both (Table 2). This category includes vasovagal, vasodepressor, situational, and carotid sinus syncope. Neurocardiogenic mechanisms are also implicated in syncope associated with ventricular outflow obstruction (such as with aortic stenosis and pulmonary embolism) as well as supraventricular tachyarrhythmias [5-9]. The second category is orthostatic hypotension, which may result from age-related physiologic changes, volume depletion, medication, and autonomic insufficiency [10, 11]. Psychiatric disorders related to syncope (such as anxiety, depression, and conversion disorders) form a third category. The fourth category includes neurologic disorders, although these rarely cause syncope unless patients with seizures are included. Neurologic causes of syncope include transient ischemia (almost exclusively involving the vertebrobasilar territory), migraines (basilar artery), and seizures (atonic seizures, temporal lobe epilepsy, and unwitnessed grand mal seizures) [12]. Table 2. Causes of Syncope Cardiac causes of syncope include coronary disease, congenital and valvular heart disease, cardiomyopathy, arrhythmias, and conduction system disorders. Coronary disease, congestive heart failure, ventricular hypertrophy, and myocarditis may set the stage for arrhythmia and syncope. Exertional syncope results from heart disease characterized by a fixed cardiac output that does not increase with exercise. Exertional syncope may also reflect arrhythmic or neurocardiogenic disorders or an anomalous coronary artery. Syncope may be the presenting symptom in elderly patients with acute myocardial infarction [13]; it rarely occurs with coronary artery spasm and aortic dissection. We used five population-based studies of unselected patients to estimate the prevalence of various causes of syncope [14-18]; the summary of these studies is necessarily limited by the variability in diagnostic criteria. The most common causes of syncope were vasovagal episode, heart disease and arrhythmias, orthostatic hypotension, and seizures. The cause of syncope could not be determined in approximately 34% of patients. All of these studies were done several years ago, and the proportion of patients with unexplained syncope is probably lower now, given wider use of event monitoring, tilt testing, electrophysiologic studies, attention to psychiatric illnesses, and recognition that the cause of syncope in elderly patients may be multifactorial. Approach to Syncope The algorithm depicted in Figure 1 provides a diagnostic approach to syncope. It is intended to provide a framework for clinical judgment, not to replace it. Key points in the algorithm that will be discussed in the text include the following. Figure 1. Algorithm for diagnosing syncope. 1. History, physical examination, and electrocardiography are the core of the workup for patients with syncope. 2. Carotid sinus massage may be useful in elderly patients but should not be done by the generalist if bruits are present, if the patient has a history of ventricular tachycardia, or in the setting of a recent stroke or myocardial infarction. A false-positive test result should be suspected if carotid massage is positive but the history does not suggest carotid hypersensitivity. 3. Special issues for elderly patients include the multifactorial nature of syncope, polypharmacy, use of carotid sinus massage, and cardiac testing (exercise stress test and echocardiography) to exclude cardiac disease. 4. Nondiagnostic arrhythmias found on Holter monitor readings should not usually be treated. 5. Intracardiac electrophysiologic studies are most useful in patients who have organic heart disease and otherwise unexplained syncope. 6. In a patient with exertional syncope, echocardiography should precede exercise stress testing. 7. The assessment of patients with a normal heart who have frequent episodes of syncope should include a loop recorder and psychiatric evaluation. 8. The workup of patients with a normal heart who have infrequent episodes of syncope should include a tilt test and psychiatric evaluation. 9. Neurologic testing, including electroencephalography, computed tomography, and carotid and transcranial Doppler ultrasonography, should be resePURPOSE To review the literature on diagnostic testing in syncope and provide recommendations for a comprehensive, cost-effective approach to establishing its cause. DATA SOURCES Studies were identified through a MEDLINE search (1980 to present) and a manual review of bibliographies of identified articles. STUDY SELECTION Papers were eligible if they addressed diagnostic testing in syncope or near syncope and reported results for at least 10 patients. DATA EXTRACTION The usefulness of tests was assessed by calculating diagnostic yield: the number of patients with diagnostically positive test results divided by the number of patients tested or, in the case of monitoring studies, the sum of true-positive and true-negative test results divided by the number of patients tested. DATA SYNTHESIS Despite the absence of a diagnostic gold standard and the paucity of data from randomized trials, several points emerge. First, history, physical examination, and electrocardiography are the core of the syncope workup (combined diagnostic yield, 50%). Second, neurologic testing is rarely helpful unless additional neurologic signs or symptoms are present (diagnostic yield of electroencephalography, computed tomography, and Doppler ultrasonography, 2% to 6%). Third, patients in whom heart disease is known or suspected or those with exertional syncope are at higher risk for adverse outcomes and should have cardiac testing, including echocardiography, stress testing. Holter monitoring, or intracardiac electrophysiologic studies, alone or in combination (diagnostic yields, 5% to 35%). Fourth, syncope in the elderly often results from polypharmacy and abnormal physiologic responses to daily events. Fifth, long-term loop electrocardiography (diagnostic yield, 25% to 35%) and tilt testing (diagnostic yield < or = 60%) are most useful in patients with recurrent syncope in whom heart disease is not suspected. Sixth, psychiatric evaluation can detect mental disorders associated with syncope in up to 25% of cases. Seventh, hospitalization may be indicated for patients at high risk for cardiac syncope (those with an abnormal electrocardiogram, organic heart disease, chest pain, history of arrhythmia, age > 70 years) or with acute neurologic signs. CONCLUSIONS Many tests for syncope have a low diagnostic yield. A careful history, physical examination, and electrocardiography will provide a diagnosis or determine whether diagnostic testing is necessary in most patients.

Managed Care, Time Pressure, and Physician Job Satisfaction: Results from the Physician Worklife Study

AbstractOBJECTIVE: To assess the association between HMO practice, time pressure, and physician job satisfaction. DESIGN: National random stratified sample of 5,704 primary care and specialty physicians in the United States. Surveys contained 150 items reflecting 10 facets (components) of satisfaction in addition to global satisfaction with current job, one’s career and one’s specialty. Linear regression-modeled satisfaction (on 1–5 scale) as a function of specialty, practice setting (solo, small group, large group, academic, or HMO), gender, ethnicity, full-time versus part-time status, and time pressure during office visits. “HMO physicians” (9% of total) were those in group or staff model HMOs with >50% of patients capitated or in managed care. RESULTS: Of the 2,326 respondents, 735 (32%) were female, 607 (26%) were minority (adjusted response rate 52%). HMO physicians reported significantly higher satisfaction with autonomy and administrative issues when compared with other practice types (moderate to large effect sizes). However, physicians in many other practice settings averaged higher satisfaction than HMO physicians with resources and relationships with staff and community (small to moderate effect sizes). Small and large group practice and academic physicians had higher global job satisfaction scores than HMO physicians (P<.05), and private practice physicians had quarter to half the odds of HMO physicians of intending to leave their current practice within 2 years (P<.05). Time pressure detracted from satisfaction in 7 of 10 satisfaction facets (P<.05) and from job, career, and specialty satisfaction (P<.01). Time allotted for new patients in HMOs (31 min) was less than that allotted in solo (39 min) and academic practices (44 min), while 83% of family physicians in HMOs felt they needed more time than allotted for new patients versus 54% of family physicians in small group practices (P<.05 after Bonferroni’s correction). CONCLUSIONS: HMO physicians are generally less satisfied with their jobs and more likely to intend to leave their practices than physicians in many other practice settings. Our data suggest that HMO physicians’ satisfaction with staff, community, resources, and the duration of new patients visits should be assessed and optimized. Whether providing more time for patient encounters would improve job satisfaction in HMOs or other practice settings remains to be determined.

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.

Predicting and preventing physician burnout: results from the United States and the Netherlands.

Burnout is a long-term stress reaction seen primarily in the human service professions. It is a “psychological syndrome of emotional exhaustion, depersonalization and reduced personal accomplishment” (1). Over the past 20 years, many aspects of medical practice have changed: autonomy is declining, the status of physicians has diminished, and work pressures are increasing. Burnout is an unintended and adverse result of such changes. Burnout has been described among physicians in several countries and practice settings; in the Netherlands, physician disability insurance premiums have recently risen 20% to 30% owing to an increasing incidence of burnout and stress-related complaints (2). Paraphrasing Maslach, Wilters (3) describes burned out physicians as being angry, irritable, and impatient; “there is also an increase in absenteeism and job turnover. Decreasing productivity and practice revenue are byproducts of physician turnover.” Thus burnout can be associated with a deterioration in the physician-patient relationship and a decrease in both the quantity and quality of care. In a recent survey of health maintenance organization (HMO) physicians (4), burned out physicians were less satisfied, more likely to want to reduce their time seeing patients, more likely to order tests or procedures, and more interested in early retirement than other physicians. To better understand the interplay of the predictors of physician burnout and to develop strategies for prevention, we compared data from two large physician surveys, one in the United States (the Physician Worklife Study) and another in the Netherlands (the Dutch Study of Motivation among Medical Consultants). These data were used to construct and test a predictive model of physician burnout.

Understanding physicians' intentions to withdraw from practice: The role of job satisfaction, job stress, mental and physical health

Health care organizations may incur high costs due to a stressed, dissatisfied physician workforce. This study proposes and tests a model relating job stress to four intentions to withdraw from practice mediated by job satisfaction and perceptions of physical and mental health. The test used a sample of 1735 physicians and generally supported the model. Given the movement of physicians into increasingly bureaucratic structures, the clinical work environment must be effectively managed.

Working Conditions in Primary Care: Physician Reactions and Care Quality

BACKGROUND Adverse primary care work conditions could lead to a reduction in the primary care workforce and lower-quality patient care. OBJECTIVE To assess the relationship among adverse primary care work conditions, adverse physician reactions (stress, burnout, and intent to leave), and patient care. DESIGN Cross-sectional analysis. SETTING 119 ambulatory clinics in New York, New York, and in the upper Midwest. PARTICIPANTS 422 family practitioners and general internists and 1795 of their adult patients with diabetes, hypertension, or heart failure. MEASUREMENTS Physician perception of clinic workflow (time pressure and pace), work control, and organizational culture (assessed survey); physician satisfaction, stress, burnout, and intent to leave practice (assessed by survey); and health care quality and errors (assessed by chart audits). RESULTS More than one half of the physicians (53.1%) reported time pressure during office visits, 48.1% said their work pace was chaotic, 78.4% noted low control over their work, and 26.5% reported burnout. Adverse workflow (time pressure and chaotic environments), low work control, and unfavorable organizational culture were strongly associated with low physician satisfaction, high stress, burnout, and intent to leave. Some work conditions were associated with lower quality and more errors, but findings were inconsistent across work conditions and diagnoses. No association was found between adverse physician reactions, such as stress and burnout, and care quality or errors. LIMITATION The analyses were cross-sectional, the measures were self-reported, and the sample contained an average of 4 patients per physician. CONCLUSION Adverse work conditions are associated with adverse physician reactions, but no consistent associations were found between adverse work conditions and the quality of patient care, and no associations were seen between adverse physician reactions and the quality of patient care.

The Work Lives of Women Physicians

AbstractOBJECTIVE: To describe gender differences in job satisfaction, work life issues, and burnout of U.S. physicians. DESIGN/PARTICIPANTS: The Physician Work life Study, a nationally representative random stratified sample of 5,704 physicians in primary and specialty nonsurgical care (N=2,326 respondents; 32% female, adjusted response rate=52%). Survey contained 150 items assessing career satisfaction and multiple aspects of work life. MEASUREMENTS AND MAIN RESULTS: Odds of being satisfied with facets of work life and odds of reporting burnout were modeled with survey-weighted logistic regression controlling for demographic variables and practice characteristics. Multiple linear regression was performed to model dependent variables of global, career, and specialty satisfaction with independent variables of income, time pressure, and items measuring control over medical and workplace issues. Compared with male physicians, female physicians were more likely to report satisfaction with their specialty and with patient and colleague relationships (P<.05), but less likely to be satisfied with autonomy, relationships with community, pay, and resources (P<.05). Female physicians reported more female patients and more patients with complex psychosocial problems, but the same numbers of complex medical patients, compared with their male colleagues. Time pressure in ambulatory settings was greater for women, who on average reported needing 36% more time than allotted to provide quality care for new patients or consultations, compared with 21% more time needed by men (P<.01). Female physicians reported significantly less work control than male physicians regarding day-to-day aspects of practice including volume of patient load, selecting physicians for referrals, and details of office scheduling (P<.01). When controlling for multiple factors, mean income for women was approximately

CLINICAL GUIDELINE: Diagnosing Syncope: Part 2: Unexplained Syncope

22,000 less than that of men. Women had 1.6 times the odds of reporting burnout compared with men (P<.05), with the odds of burnout by women increasing by 12% to 15% for each additional 5 hours worked per week over 40 hours (P<.05). Lack of workplace control predicted burnout in women but not in men. For those women with young children, odds of burnout were 40% less when support of colleagues, spouse, or significant other for balancing work and home issues was present. CONCLUSIONS: Gender differences exist in both the experience of and satisfaction with medical practice. Addressing these gender differences will optimize the participation of female physicians within the medical workforce.

Management of Vasovagal Syncope

In the first part of this two-part study [1], the differential diagnosis of syncope was examined with respect to the information provided by results of the history, physical examination, and electrocardiography; an algorithmic approach to the diagnosis of syncope was also introduced. A careful history and physical examination are mandatory in all patients with syncope because they are the keys to determining whether additional diagnostic testing is required. Electrocardiography is recommended for almost all patients with syncope, whereas specialized neurologic testing is suggested only in certain circumstances: for example, computed tomography for patients with focal neurologic signs, electroencephalography for patients with seizure activity, or carotid or transcranial Doppler ultrasonography for patients with carotid bruits or a history of neurovascular symptoms. This paper addresses the workup of patients with syncope that is unexplained by the results of history, physical examination, or surface 12-lead electrocardiography. Unexplained Syncope Syncope that remains unexplained after initial clinical assessment is of considerable concern to the practicing clinician. The algorithm that we developed provides three branches for unexplained syncope: one for patients known to have or suspected of having heart disease, one for elderly patients, and one for patients not known to have or suspected of having heart disease (Figure 1). Figure 1. Algorithm for diagnosing syncope. Branch 1: Unexplained Syncope with Clinical Organic Heart Disease or Abnormal Electrocardiogram Organic heart disease is often known, discovered, or suspected in patients who have sudden or exertional syncope. Evaluation of patients known to have or suspected of having heart disease often begins with echocardiography or an exercise stress test to determine and quantify the degree of heart disease. If the results of these tests are negative, further cardiac testing can often be avoided. If the results are positive, however, subsequent testing may include Holter monitoring or telemetry, signal-averaged electrocardiography, and intracardiac electrophysiologic studies. Echocardiography No studies have been specifically designed to assess the usefulness of echocardiography in syncope. In patients known to have or suspected of having heart disease, patients suspected of having arrhythmias, or patients with abnormal electrocardiograms, echocardiography is an important initial step in diagnostic testing. Unsuspected findings on echocardiography are reported in only 5% to 10% of unselected patients [2]. This yield is similar to that of 12-lead electrocardiography, but echocardiography is 7 times more expensive. The cost-effectiveness of echocardiography in diagnosing the cause of syncope has yet to be determined. Exercise Testing Exercise stress testing can be used for the evaluation of exertional syncope to diagnose ischemia or exercise-induced tachyarrhythmias or to reproduce exercise-associated or postexertional syncope. In one population study of patients with syncope, the yield of the exercise stress test was less than 1% [3]. No data are available to determine the yield for ischemia or exercise-induced tachyarrhythmias or to define the tests usefulness in diagnosing exercise-associated syncope. Tilt-table testing has been used to diagnose neurally mediated syncope, which may manifest as postexertional syncope [4, 5]. Exercise stress testing is recommended if patients have exercise-associated syncope and if the results of clinical evaluation suggest ischemic heart disease. In patients with exertional syncope, echocardiography should be done first to exclude hypertrophic cardiomyopathy. 24-Hour Holter Monitoring We summarize the results of ambulatory monitoring in syncope by determining the presence or absence of arrhythmias in patients who develop symptoms during monitoring [6]. In studies that evaluated syncope or presyncope with 12 or more hours of monitoring and reported on symptoms, 4% of patients had correlation of symptoms with arrhythmias (Table 1) [7-14]. In about 15% of patients, symptoms were not associated with arrhythmias; this finding excluded rhythm disturbance as a cause for syncope in these patients (overall diagnostic yield in 8 studies, 4% + 15% = 19%). No symptoms occurred in approximately 79% of patients, but arrhythmias were found in 14% [7-14]. The causal relation between most of these arrhythmias and syncope is uncertain, although certain uncommon asymptomatic arrhythmias (prolonged sinus pauses, Mobitz type II block, and sustained ventricular tachycardia during sleep) usually prompt appropriate treatment. If no arrhythmias are found and no symptoms occur during monitoring, arrhythmic syncope is not necessarily excluded; this is because of the episodic nature of arrhythmias. In patients with a high pretest likelihood of arrhythmias (for example, patients who have brief loss of consciousness with short or absent prodrome, an abnormal electrocardiogram, or organic heart disease), further evaluation for arrhythmias should be pursued by event monitoring or electrophysiologic studies. Table 1. Yield of Prolonged Electrocardiographic (Holter) Monitoring in Syncope Only one study evaluated the effect of duration of monitoring on diagnostic yield [7]. Extending monitoring to 72 hours increased the number of arrhythmias detected (14.7% on the first day, an additional 11.1% the second day, and an additional 4.2% the third day) but not the yield for arrhythmias associated with symptoms. A 24-hour Holter monitor or inpatient telemetry is recommended when symptoms suggest arrhythmic syncope (brief loss of consciousness, no prodrome, palpitations with syncope) and in patients who have syncope of unexplained cause, heart disease, or an abnormal electrocardiogram. Loop monitoring may be a reasonable alternative in patients with recurrent syncope and a normal heart. Intracardiac Electrophysiologic Studies Although they are relatively safe in patients with syncope [15], electrophysiologic studies are expensive and invasive. Such studies are associated with low risks for pulmonary embolism, cardiac perforation, arteriovenous fistulae, and myocardial infarction (cumulative risk < 3%) [16]. Electrophysiologic studies use electric stimulation and monitoring to discover conduction abnormalities that predispose patients to bradyarrhythmias and to determine a patients propensity for developing tachyarrhythmias (both ventricular and supraventricular). Most protocols for programmed stimulation include three extrastimuli at one or two ventricular sites. More aggressive protocols, including the use of isoproterenol, may increase the sensitivity but decrease the specificity of tests for detecting tachyarrhythmias. The most important outcome of electrophysiologic testing is the diagnosis of ventricular tachycardia. Other potentially important diagnostic outcomes include supraventricular tachycardias and bradyarrhythmias. Because only a few studies have used 24-hour Holter monitoring to confirm results of electrophysiologic studies [17, 18], the true diagnostic yield of this testing is generally unknown. Nevertheless, it is agreed that the results of an electrophysiologic test are considered positive if the test uncovers any of the following: 1) sustained monomorphic ventricular tachycardia [not including polymorphic ventricular tachycardia or ventricular fibrillation, which may be nonspecific responses], 2) a prolonged corrected sinus node recovery time longer than 1000 milliseconds, 3) markedly prolonged HV intervals longer than 90 milliseconds, 4) spontaneous or induced infra-Hisian block, and 5) supraventricular tachycardia with hypotension. For the accompanying analysis, we used the above definitions wherever possible, excluding supraventricular tachycardias (which are relatively uncommon outcomes of electrophysiologic testing in syncope and can be diagnosed by other means). Our primary purpose was to classify study results to determine predictors of positive results on electrophysiologic studies. Key predictors that we assessed were presence of organic heart disease and brady-arrhythmic abnormalities (such as conduction-system disease) found on 12-lead electrocardiography. Fourteen studies evaluating 1423 patients provided information on electrophysiologic outcomes but had insufficient detail to assess the importance of organic heart disease and baseline electrocardiography [19-32]. Heart disease was present in slightly more than half of the patients. Ventricular tachycardia was diagnosed in 14%, whereas a bradycardic outcome was observed in 21%. Because some patients (about 10%) had both tachycardic and bradycardic outcomes, the overall diagnostic yield in these studies (in which a high prevalence of patients had organic heart disease) was approximately 32% [14% ventricular tachycardia + 21% bradycardias 10% x (14 + 21)]. Table 2 summarizes eight additional studies in which the contribution of organic heart disease to a positive test result could be assessed [15, 17, 18, 33-37]. In these studies, 625 patients underwent electrophysiologic testing for syncope. Of the 406 patients with organic heart disease or an abnormal electrocardiogram, 21% had ventricular tachycardia and 34% had a bradycardia during the electrophysiologic study. Of the 219 patients with normal hearts, only 1% had ventricular tachycardia and 10% had a documented bradycardia (P < 0.001 for both comparisons). In these studies, approximately 14% of patients who could be given a diagnosis had both ventricular tachycardia and bradycardia. Thus, the diagnostic yield of electrophysiologic studies was almost 50% in patients with organic heart disease and about 10% in patients with a normal heart. Table 2. Diagnostic Yield of Intracardiac Electrophysiologic Studies in Syncope: Importance of Organic Heart Disease* These data are further elucidated by Table 3, which describes six referral stPURPOSE To review the literature on diagnostic testing in syncope that remains unexplained after initial clinical assessment. DATA SOURCES MEDLINE search. STUDY SELECTION Published papers were selected if they addressed diagnostic testing in syncope, near syncope, or dizziness. DATA EXTRACTION Studies were identified as population studies, referral studies, or case series. DATA SYNTHESIS After a thorough history, physical examination, and electrocardiography, the cause of syncope remains undiagnosed in 50% of patients. In such patients, information may be derived from the results of carefully selected diagnostic tests, especially 1) electrophysiologic studies in patients with organic heart disease, 2) Holter monitoring or telemetry in patients known to have or suspected of having heart disease, 3) loop monitoring in patients with frequent events and normal hearts, 4) psychiatric evaluation in patients with frequent events and no injury, and 5) tilt-table testing in patients who have infrequent events or in whom vasovagal syncope is suspected. Hospitalization is indicated for high-risk patients, especially those with known heart disease and elderly patients. CONCLUSIONS A flexible, focused approach is required to diagnose syncope. Features of the initial history and physical examination help guide diagnostic testing.