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Chapter 99. Syncope

Kush Agrawal, MD; Robert Young, MD; Daniel D. Dressler, MD, MSc, SFHM

  1. What diagnostic testing should be considered for common causes of syncope?

  2. When do clinicians need to rule out arrhythmias and how is this done?

  3. What are the diagnostic criteria for neurocardiogenic syncope?

  4. When do patients require hospital admission?

  5. How do elderly patients differ from younger patients?

  6. How should the history and physical examination be utilized to direct further testing or limit further testing in the evaluation of syncope?

  7. What are the indications for advanced noninvasive or invasive tests in the evaluation of syncope?

Definition

Syncope is defined as a sudden, transient loss of consciousness and postural tone with rapid spontaneous recovery. Syncope results from cerebral hypoperfusion to the reticular activating system in the brain stem. Any condition that does not result from cerebral hypoperfusion should not be classified as syncope.

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Case 99-1

A 74-year-old female with early Parkinson disease presented to the Emergency Department with loss of consciousness while standing in the sun. She thought that she did not drink enough water during the day. She initially felt bilateral shoulder pain followed by dizziness, and then recalled awakening on her porch. She injured her forearm, but recovered fully within one minute. A witness described some brief jerking movements in her arms (lasted a few seconds). Blood pressure lying and standing were 130/80 mm Hg and 90/48 mm Hg respectively. Pulse was 86 beats per minute (bpm) lying and 88 bpm standing. Other vital signs, cardiac, and neurologic examination were all normal. An electrocardiogram (ECG) showed normal sinus rhythm with a heart rate of 88 bpm.

What is the approach to the patient? What further testing is indicated? What is the diagnosis? What is her overall prognosis following this syncopal event?

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Case 99-2

A 62-year-old male passed out while voiding just after awakening from sleep. He denied symptoms beforehand and awakened promptly. On further history, he did not report prior cardiovascular symptoms. His past medical history includes long-standing hypertension and he has a 40-pack-per-year tobacco history. Cardiovascular and neurologic examination was normal. Breath sounds were distant. His ECG is shown in Figure 99-1.

What is the best approach to this patient? What further testing is indicated? What is the diagnosis? What is his prognosis if left untreated?

Figure 99-1
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ECG, First-degree atrioventricular (AV) block with right bundle branch block (RBBB) and left anterior fascicular block (LAFB).

Epidemiology

Syncope has a 3% incidence in the general population and 6% incidence in persons over age 75 years. It is responsible for up to 5% of emergency department (ED) visits and up to 3% of hospital admissions. The median cost of hospitalization of patients with syncope is approximately $8500, and many (up to ...

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