Syncope resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Karol Gema Hernandez, M.D. [2]; Alejandro Lemor, M.D. [3]

Syncope Resident Survival Guide Microchapters
Overview
Causes
Diagnosis
Treatment
Do's
Don'ts

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Overview

Syncope is the transient loss of consciousness (LOC) due to cerebral hypoperfusion and it is characterized by a rapid onset, a short duration and a spontaneous complete recovery. It is extremely important to identify the cause of the syncope and recognize high risk patients (order a EKG to look for heart disease as a possible cause). The initial management would depend on the etiology of the syncope(reflex, orthostatic hypotension or cardiovascular).

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Hemorrhage
• Hypotension
• Hypoxia
• Ruptured abdominal aortic aneurysm
• Ventricular arrhythmia

Common Causes

• Arrhythmia
• Medication (vasodilators, diuretics, antiarrhythmics, antipsychotics)
• Orthostatic hypotension
• Vagal stimulation
• Vertebrobasilar insufficiency

Diagnosis

Shown below is an algorithm summarizing the diagnostic approach to syncope based on the 2009 ESC Guidelines for the Diagnosis and Management of Syncope.

Abbreviations: TIA:Transient ischemic attack; EEG:Electroencephalography; HF: Heart failure; AF: Atrial fibrillation: SVT: Supraventricular tachycardia ; VT:Ventricular tachycardia: MI: Myocardial infarction; BBB: Bundle branch block

Characterize symptoms ❑ Loss of consciousness (LOC) ❑ Rapid onset ❑ Short duration ❑ Spontaneous complete recovery ❑ Prodrome (diaphoresis, nausea, blurry vision) ❑ Chest pain ❑ Palpitations ❑ Bowel or bladder incontinence ❑ Activity prior to LOC (driving, machine operation, flying, competitive athletics) ❑ Position prior to LOC ❑ Supine ❑ Sitting ❑ Standing Inquire about medications intake: ❑ Nitrate ❑ Diuretics ❑ Antiarrhythmic ❑ Alpha blocker ❑ Beta blocker ❑ ACE inhibitors or ARB ❑ Hydralazine ❑ Ethanol ❑ Benzodiazepines ❑Antipsychotics ❑ Tricyclic antidepressants ❑ Barbiturates Obtain a detailed past medical history: ❑ Previously healthy ❑ Previous syncope episodes ❑ Cardiovascular disease (arrhythmia, valvular disease, heart failure) ❑ Neurological diseases (Parkinson's disease, Diabetic neuropathy) ❑ Recent trauma

Identify possible triggers: ❑ Emotional stress ❑ Change in position ❑ Fatigue ❑ Exertion ❑ Warm weather ❑ Prolonged standing ❑ Cough ❑ Micturition ❑ Defecation ❑ Swallowing ❑ Head motion ❑ Arm motion ❑ Shaving ❑ Trauma

❑ Examine the patient ❑ Heart rate ❑ Blood pressure: look for orthostatic hypotension or hypotension ❑ Cardiac examination: look for palpitations, bruits, murmurs (aortic stenosis or pulmonary stenosis) ❑ Neurological examination: look for focal abnormalities (could indicate a stroke) ❑ Pulmonary examination: look for rales (suggestive of HF)

❑ Order an EKG ❑ Order a stool guaiac test (to look for GI bleeding) ❑ Order electrolytes, glucose, ABG) (search for metabolic disorders: hypoglycemia, hyponatreamia, hypernatremia, hypokalemia, hypoxia) ❑ Order blood and urine toxicology tests (if intoxication is suspected)

Rule out other possible diagnoses: With loss of consciousness: ❑ Coma (Glasgow Scale < 8, profound state of unconsciousness) ❑ Sudden cardiac arrest (absence of pulse) ❑ Epilepsy (inquire past medical history) ❑ Perform neurological evaluation ❑ Perform tilt testing, preferably with concurrent EEG and video monitoring if doubt of mimicking epilepsy ❑ Metabolic disorders (order electrolytes, glucose, ABG): ❑ Hypoglycemia ❑ Hypoxia ❑ Hyperventilation with hypocapnia ❑ Intoxication ❑ Vertebrobasilar TIA Without loss of consciousness: ❑ Cataplexy ❑ Drop attacks ❑ Functional /psychogenic pseudosyncope (patients with conversion disorder) ❑ TIA

❑ Determine the etiology of the syncope

Reflex

Orthostatic hypotension

Cardiovascular

Findings: ❑ Heart rate: tachycardia, normal or bradycardia ❑ Absence of heart disease ❑ History of recurrent syncope ❑ After unpleasant sight or odor ❑ Associated to nausea ❑ Head rotation or pressure to carotid sinus ❑ Neurological system: look for focal neurologic signs ❑ EKG: tachycardia, normal or bradycardia

Findings: ❑ Blood pressure (BP): ❑ Measure in both arms, while standing and supine ❑ Fall in systolic BP ≥ 20 mmHg and/or in diastolic BP of at least≥ 10 mmHg between the supine and sitting BP reading ❑ Heart rate: tachycardia ❑ Cardiac evaluation: palpitations ❑ After standing up or prolonged standing ❑ Start of new antihypertensive drug ❑ Presence of autonomic neuropathy ❑ EKG: tachycardia or normal

Findings: ❑ Heart rate: ❑ Tachycardia (in patients with arrhythmia) ❑ Normal ❑ Bradycardia (in patients with heart block) ❑ Cardiac evaluation: palpitations, carotid bruits, murmurs (search for aortic stenosis or pulmonary stenosis) ❑ Presence of structural hearth disease ❑ During exertion ❑ Abnormal EKG findings: ❑ Mobitz I second degree AV block ❑ Non-sustained VT ❑ Premature QRS complexes ❑ Wide QRS(≥ 0.12 s) ❑ Long or short QT intervals ❑ Early repolarization ❑ Q waves (myocardial infarction) ❑ Bifascicular block

Management

Shown below is an algorithm summarizing the therapeutic approach to syncope based on the 2009 ESC Guidelines for the Diagnosis and Management of Syncope.

Abbreviations: AF: Atrial fibrillation: SVT: Supraventricular tachycardia ; VT:Ventricular tachycardia: MI: Myocardial infarction; BBB: Bundle branch block

❑ Determine the etiology of the syncope

Reflex

Orthostatic hypotension

Cardiovascular

❑ Explain diagnosis, provide reassurance ❑ Explain risk of recurrence and avoidance of triggers ❑ Isometric physical counterpressure maneuvers (PCM) in patients with prodrome: ❑ Hand grip and arm tensing ❑ Leg crossing

❑ Adequate hydration and salt intake ❑ Adjunctive therapy if needed: ❑ Midodrine 10 mg PO q8hr or ❑ Fludrocortisone 0.1 mg/day PO

Depends on the cause of the arrhythmia: ❑ Schedule for cardiac pacing: patients with sinus node disease, Mobitz II AV block, BBB with positive electrophysiological study ❑ Schedule for catheter ablation: patients with SVT and VT in absence of structural hearth disease ❑ Administer antiarrhythmic drug therapy: patients with AF, failed catheter ablation ❑ Schedule for implantable cardioverter defibrillator: patients with VT with heart disease, electrophysiological study induced VT in patients with previous MI, VT and inherited cardiomyopathy

Do's

• Tilt testing is indicated when it is of clinical value to demonstrate susceptibility to reflex syncope to the patient.
• Tilt testing should be considered to discriminate between reflex and OH syncope.
• Perform tilt testing if psychiatric disease.
• Tilt testing may be considered for differentiating syncope with jerking movements from epilepsy.
• If syncope happened after standing up position, there should be documentation with active standing or tilt testing in order to diagnose orthostatic hypotension.
• Perform carotid sinus massage if patient >40 years with syncope of unknown etiology after initial evaluation.
• If multiple unexplained falls; perform tilt testing.
• Consider implantable loop recorder before embarking on cardiac pacing in patients with suspected or certain reflex syncope presenting with frequent or traumatic syncopal episodes.
• Evaluate neurologically if syncope is due to autonomic failure, to evaluate underlying disease.

Don'ts

• Don't perform carotid sinus massage in patients with previous TIA or stroke within the past 3 months and in patients with carotid sinus bruits (except if carotid sinus Doppler studies excluded significant stenosis.
• Don't use tilt testing for assessment of treatment.
• Don't perform isoproterenol tilt testing in patients with ischemic heart disease.
• Don't use adenosine stress test as a diagnostic test to select patients for cardiac pacing, owing to lack of correlation with spontaneous syncope.
• Don't perform electrophysiologic study if there is already indication for ICD in patients with ischemic heart with suspected arrhythmic cause.
• Don't perform electrophysiologic study in patients with normal EKG, no heart disease, and no palpitations.

References

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