Identifying High Risk Patients With Syncope
Identifying High Risk Patients With Syncope
To validate two models which categorized patients with syncope into high and low risk for
 either sudden death or diagnostic arrhythmias based on data available from the initial
 history, physical examination, and electrocardiogram.
BACKGROUND:

 Syncope is a common medical problem with up to 30 percent of normal individuals reporting one
 or more syncopal episodes. Thus, physicians of all specialties are frequently confronted by
 patients with syncope. The spectrum of diseases which may cause syncope is broad, ranging
 from common benign problems to severe life-threatening disorders. Because of the complexity
 of the clinical situation when an obvious cause for syncope is not found, patients may be
 subjected to a significant period of hospitalization and a large number of diagnostic tests.
 Retrospective and prospective studies have shown that many diagnostic tests are frequently
 employed but are infrequently diagnostic of a cause of syncope. Thus, studies have shown that
 when a cause is established or suggested, the majority of diagnoses are assigned based on
 initial history and physical examination. An initial electrocardiogram is helpful in
 assigning a cause of syncope in only approximately five percent of additional patients. In a
 prior study prolonged electrocardiographic monitoring was helpful in assigning a cause of
 syncope in approximately fifteen percent of patients. Other studies of prolonged
 electrocardiographic monitoring in patients with syncope reveal that arrhythmias as a
 potential cause of syncope are found in eleven to sixty-four percent of patients. Diagnostic
 procedures such as EEG, head CT scan, brain scan, cerebral angiography, echocardiography, and
 cardiac catheterization rarely establish a cause of syncope but are useful when employed
 selectively for diagnosis of specific etiologies of syncope.

 These studies of diagnostic evaluation of syncope, therefore, clearly indicate that there is
 a subgroup of patients with syncope who have arrhythmias as a cause of their syncope which
 were not apparent from initial history, physical examination, and EKG. Therefore, prolonged
 electrocardiographic monitoring has assumed a central role in the diagnostic evaluation of
 this group of patients for detection of arrhythmias. Because of the prognostic and
 therapeutic importance of arrhythmias causing syncope, it is important to identify patients
 who are likely to have arrhythmias from the data available at presentation. There were no
 studies prior to 1987 attempting to identify such patients at presentation. The predictors of
 diagnostic arrhythmias at presentation may be helpful for four reasons. First, the variables
 suggesting high likelihood of arrhythmias may provide a basis for decisions regarding the
 need for hospital admission. Secondly, predictors of diagnostic arrhythmias may identify
 patients who may need to be monitored immediately as opposed to electively. Thirdly, patients
 who have predictors of diagnostic arrhythmias may be more appropriate candidates for invasive
 diagnostic testing such as intracardiac electrophysiologic studies. Fourthly, since patients
 with arrhythmias are at high risk of sudden death, these predictors may identify an
 appropriate subset of patients for further studies involving therapeutic interventions. Since
 many patients with syncope have multiple risk factors for sudden death, the development of a
 multifactorial model to more effectively and expeditiously predict the degree of risk of
 sudden death may be important in the management of patients with syncope after initial
 presentation.

 DESIGN NARRATIVE:

 Two models were validated in this longitudinal study including one which predicted sudden
 death and one which predicted diagnostic arrhythmias on monitoring. The model for prediction
 of sudden death was developed in patients in whom a cause of syncope was not established by
 initial history and physical examination. The predictors in this model included a history of
 diabetes mellitus, renal insufficiency, left ventricular hypertrophy, left bundle branch
 block, and left axis deviation. The model of predictors of diagnostic arrhythmias was
 developed in patients in whom a cause of syncope was not established from initial history,
 physical examination, or EKG and included a history of ventricular tachycardia and an
 abnormal EKG by specific criteria.

 Patients with syncope were accrued from the emergency room, the inpatient services and the
 ambulatory clinics of the Presbyterian University Hospital of Pittsburgh. All patients
 underwent a basic standardized evaluation consisting of a history, physical examination,
 baseline laboratory tests, electrocardiogram, prolonged electrocardiographic monitoring, and
 special diagnostic tests as necessary. Diagnosis of a cause of syncope was assigned by
 standardized criteria. Follow-up information regarding sudden death and mortality was
 obtained at three-month intervals until the end of the study. Causes of death were assigned
 in a standardized manner.

 The study completion date listed in this record was obtained from the "End Date" entered in
 the Protocol Registration and Results System (PRS) record.
No eligibility criteria