Mount Carmel Health Partners Clinical Guidelines Syncope | Page 2

Quick Guide to Syncope

• Syncope is most often benign and self-limited

• The distribution of causes for syncope are as follows : ▫ reflex ( including neurally mediated and vasovagal ): 58 % ▫ cardiac disease : 23 % ▫ neurologic or psychiatric disease : 1 % ▫ unexplained syncope : 18 %

• Up to 40 % of the population will experience at least one episode of TLOC ( transient loss of consciousness ) in their lifetime

• Patients age 70 and older are at a greater risk for syncope

Syncope is thought be responsible for approximately 3 % of emergency room visits and 2-6 % of inpatient admissions each year .

Evaluation

Syncope is a common presenting complaint in a primary care setting , and at least 90 % of the time reflects either neurocardiogenic Syncope ( NCS ) or orthostatic hypotension ( OH ). More malignant etiologies are significantly less likely , although possible . The goal of the initial evaluation is to evaluate the patient for the common etiologies and exclude high risk features .

The patient ’ s history and a physical examination are the most specific and sensitive ways to evaluate syncope . In up to 85 % of patients , the determination of what caused the syncopal episode can be achieved with a thorough history and physical exam , including orthostatic blood pressures . Attention should be paid to both the description of syncope and to questioning about symptoms of either ischemic disease or heart failure .

A detailed account of the event must be obtained from the patient and / or witnesses of the event . This account should include the circumstances surrounding the episode , such as the precipitant factors , the activity in which the patient was involved prior to the event , and the patient ' s posture when it occurred . Activity prior to the event may give clues to the etiology of symptoms . Syncope may occur at rest , with a change of posture , during exertion , after exertion , or with specific activities such as shaving , coughing , voiding , or prolonged standing . Assess whether a patient was standing , sitting , or lying when the syncope occurred . Syncope while seated or lying down is more likely to be cardiac .

A medication history must be obtained in all patients with syncope , with special emphasis placed on cardiac and antihypertensive medications . Drugs commonly implicated in syncope include the following :

• agents that reduce blood pressure ( e . g ., antihypertensives , diuretics , nitrates )

• agents that affect cardiac output ( e . g ., beta blockers , digitalis , antiarrhythmics )

• agents that prolong the cardiac output ( QT ) interval ( e . g ., tricyclic antidepressants , phenothiazines , quinidine , amiodarone )

• agents that alter sensorium ( including alcohol and analgesics with sedative properties )

• agents that alter serum electrolytes ( especially diuretics )

Inquiry must be made into any personal or familial past medical history of cardiac disease . Patients with a history of myocardial infarction ( MI ), arrhythmia , structural cardiac defects , cardiomyopathies , or congestive heart failure ( CHF ) have a uniformly worse prognosis than other patient groups .

Basic labs including CBC and BMP are not necessary , if the presentation is of a single event with obvious etiology in a young and apparently healthy patient .

If the evaluation is characteristic of either neurocardiogenic syncope or orthostatic hypotension , the ECG is normal , and the patient does not have other high risk features such as exertional angina or signs and symptoms of heart failure , then no further testing is indicated . A diagnosis should be made of either NCS or OH ( or both ) and the patient treated accordingly .

If the ECG is abnormal , an echocardiogram should be obtained to exclude significant structural heart disease . If exertional angina is present , stress testing should be considered .

A patient with a normal ECG , near normal BNP , and no signs of ischemia or heart failure has an extremely low risk of ventricular fibrillation .

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