Rosen & Barkin's 5-Minute Emergency Medicine Consult (85 page)
Read Rosen & Barkin's 5-Minute Emergency Medicine Consult Online
Authors: Jeffrey J. Schaider,Adam Z. Barkin,Roger M. Barkin,Philip Shayne,Richard E. Wolfe,Stephen R. Hayden,Peter Rosen
Tags: #Medical, #Emergency Medicine
BOOK: Rosen & Barkin's 5-Minute Emergency Medicine Consult
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ICD9
Edward Ullman
•
Terrance T. Lee
BASICS
DESCRIPTION
DIAGNOSIS
SIGNS AND SYMPTOMS
Lab
TREATMENT
PRE HOSPITAL
- 334.2 Primary cerebellar degeneration
- 334.3 Other cerebellar ataxia
- 781.3 Lack of coordination
ICD10
ATRIAL FIBRILLATION- G11.1 Early-onset cerebellar ataxia
- G11.9 Hereditary ataxia, unspecified
- R27.0 Ataxia, unspecified
Edward Ullman
•
Terrance T. Lee
BASICSDESCRIPTION
- Dysrhythmia characterized by seemingly disorganized atrial depolarizations without effective atrial contraction
- Caused by multiple re-entrant waveforms within the atria
- Atrial rate ranges from 350–600 beats per minute (bpm).
- Results in loss of organized atrial contractions and rapid ventricular rate:
- Decrease in cardiac output
- Prone to embolus formation
- Decrease in cardiac output
- Most common clinical arrhythmia:
- Prevalence increasing with age
- Men are at higher risk
- Prevalence increasing with age
- Systemic disease:
- HTN
- Hyperthyroidism
- Chronic pulmonary disease
- Infection
- Pulmonary embolus
- Hypoxia
- Drugs (e.g., sympathomimetics)
- Acute alcohol ingestion (holiday heart syndrome)
- Obesity
- Electrolyte disturbance
- Thyroid disease
- HTN
- Underlying cardiac disease:
- Cardiomyopathy
- CAD
- Valvular disease, especially mitral
- Pericarditis
- Sick sinus syndrome
- Myocardial contusion
- CHF
- Congenital heart disease
- Cardiomyopathy
- Idiopathic:
- Absence of any known etiologic factor
- No clinical or echocardiographic evidence of heart disease
- Absence of any known etiologic factor
DIAGNOSISSIGNS AND SYMPTOMS
- Palpitations
- Decreased cardiac output:
- Weakness
- Light headedness
- Syncope
- Hypotension
- Angina
- Pulmonary edema
- Altered mental status
- Lower extremity edema
- Hepatojugular reflex
- Weakness
- Embolus formation:
- Acute neurologic injury
- Mesenteric ischemia
- Acute neurologic injury
- Onset of symptoms
- Duration
- Inciting factors
- Prior episodes of fibrillation
- Prior heart disease
- Palpitations
- Irregularly irregular pulse
- Absence of A
-
waves in the jugular venous pulse - Pulse deficit with more rapid ventricular rates:
- The auscultated or palpated apical rate is faster than the rate palpated at the wrist
- The auscultated or palpated apical rate is faster than the rate palpated at the wrist
- History and physical exam:
- Assess for instability and need for immediate cardioversion
- Duration of symptoms >48 hr or <48 hr
- Evidence of systemic disease or underlying cardiac disease
- Assess for instability and need for immediate cardioversion
- ECG: Signs of congestive heart failure
- Absent P-waves replaced by fibrillatory (f) waves, 350–600 bpm
- F-waves vary in amplitude, morphology, and intervals
- R-R intervals are irregularly irregular
- Absence of an isoelectric baseline
- Ventricular rate ranges from 80–150 bpm:
- If rate >200 associated with wide-irregular QRS, consider bypass tract
- If rate >200 associated with wide-irregular QRS, consider bypass tract
- Slower rate suggests abnormal AV node or presence of AV nodal blocking medication
- Usually narrow QRS complexes unless:
- Functional aberration
- Pre-existing bundle branch
- Pre-excitation with an accessory pathway
- Functional aberration
- Absent P-waves replaced by fibrillatory (f) waves, 350–600 bpm
Lab
- CBC
- Electrolytes
- Cardiac enzymes—if ischemia is a concern
- Thyroid function
- Digoxin level—if patient is taking
- Anticoagulation parameters
- Urine drug screen
- CXR
- ECG
- Atrial flutter with variable AV block
- Multifocal atrial tachycardia
- Sinus rhythm with frequent premature atrial contractions
- Atrial tachycardia with variable AV block
TREATMENTPRE HOSPITAL
- IV access
- Monitor
- Oxygen
- Cardioversion:
- In settings where patient is unstable
- In settings where patient is unstable
- IV
- Oxygen
- Monitor
- Immediate synchronized electrical cardioversion starting at 200 J if the patient is unstable
- Hemodynamically unstable and life threatening:
- Myocardial infarction, pulmonary edema, heart failure that does not respond promptly to pharmacological measures
- Synchronized electrical cardioversion
- Biphasic: Start at 100 J, higher success rate
- Monophasic: Start at 200 J
- Sx duration <48 hr: Consider IV heparin bolus prior.
- Sx duration >48 hr: IV heparin, transesophageal echo to exclude atrial clot, cardioversion. Anticoagulate for 4 wk. Do not delay echo if life-threatening arrhythmia.
- Consider pretreatment with antiarrhythmic drugs and use anterior–posterior pad placement to increase likelihood of success
- Biphasic: Start at 100 J, higher success rate
- Chemical cardioversion:
- Choice of drug depends on history of CHF, high BP, LV hypertrophy, and CAD
- Medications may be proarrhythmic and should be used with caution
- As with electrical cardioversion, appropriate anticoagulation will be necessary depending on the duration and presence/absence of clot
- Ibutilide
- Procainamide
- Flecainide
- Propafenone
- Sotalol
- Choice of drug depends on history of CHF, high BP, LV hypertrophy, and CAD
- Myocardial infarction, pulmonary edema, heart failure that does not respond promptly to pharmacological measures
- Hemodynamically stable, mildly symptomatic:
- Treat underlying cause if 1 is identified.
- Identify if symptoms are <48 hr. If so consider synchronized cardioversion.
- >48 hr: Rhythm control does not offer mortality benefit over rate control
- Use procainamide to treat stable patients with a suspected bypass tract
- Rate control:
- Not necessary if rate <100 bpm or if rhythm spontaneously converts to sinus
- AV nodal blockers (calcium channel blockers, β-blockers, and digoxin) contraindicated if bypass tract suspected such as WPW
- Calcium channel blockers: Consider in patient with pulmonary disease. Use cautiously in patient with uncompensated CHF and 2nd- or 3rd-degree heart block
- β-blockers: Consider in patient with coronary artery disease (CAD). Use cautiously in patient with uncompensated CHF, 2nd- or 3rd-degree heart block, and pulmonary disease
- Digoxin: Consider in patient with pre-existing CHF.
- Amiodarone: Consider in refractory atrial fibrillation
- Not necessary if rate <100 bpm or if rhythm spontaneously converts to sinus
- Rhythm control and prophylaxis:
- Includes procainamide, sotalol, amiodarone, dofetilide
- Amiodarone: Only agent with strong data to support initiation for outpatient treatment
- Includes procainamide, sotalol, amiodarone, dofetilide
- Elective cardioversion:
- Oral anticoagulation with therapeutic levels for 3 wk prior to and 4 wk after
- Oral anticoagulation with therapeutic levels for 3 wk prior to and 4 wk after
- Stable patients with atrial fibrillation and WPW can be treated with procainamide or ibutilide, although cardioversion may be preferred
- Treat underlying cause if 1 is identified.
- Anticoagulation determined by CHADS2 scoring:
- 1 point for each of the following:
- History of cardiac failure
- History of HTN
- Age ≥75 yr
- Diabetes
- History of cardiac failure
- 2 points for a history of stroke or TIA
- Score of 0:
- 81–325 mg/day of aspirin
- 81–325 mg/day of aspirin
- Score of 1:
- Either 81–325 mg/day of aspirin or adjusted-dose warfarin with a target INR of 2.5
- Either 81–325 mg/day of aspirin or adjusted-dose warfarin with a target INR of 2.5
- Score >1:
- Adjusted-dose warfarin with a target INR of 2.5 (range 2–3)
- Adjusted-dose warfarin with a target INR of 2.5 (range 2–3)
- Adjusted annual stroke rate increases from 1.9% for a CHADS2 score of 0 to 18.2% for a CHADS2 score of 6
- Aspirin:
- Patients with contraindications to anticoagulation and unreliable individuals
- Patients with low stroke risk
- Patients with contraindications to anticoagulation and unreliable individuals
- 1 point for each of the following:
- Metoprolol:
- 5–10 mg slow IV push at 5 min intervals to total of 15 mg
- 25 mg–100 mg oral BID
- 5–10 mg slow IV push at 5 min intervals to total of 15 mg
- Diltiazem:
- 0.25 mg/kg IV over 2 min; if unsuccessful, repeat in 15 min as 0.35 mg/kg IV over 2 min; maintenance infusion of 5 mg/h usually started to maintain rate control.
- 120–300 mg oral daily
- 0.25 mg/kg IV over 2 min; if unsuccessful, repeat in 15 min as 0.35 mg/kg IV over 2 min; maintenance infusion of 5 mg/h usually started to maintain rate control.
- Digoxin:
- 0.5 mg IV initially, then 0.25 mg IV q4h until desired effect
- 0.5 mg IV initially, then 0.25 mg IV q4h until desired effect
- Esmolol:
- 0.5 mg/kg over 1 min; maintenance infusion at 0.05 mg/kg/min over 4 min
- 0.5 mg/kg over 1 min; maintenance infusion at 0.05 mg/kg/min over 4 min
- Propranolol:
- 0.1 mg/kg IV divided into equal doses at 2–3 min intervals
- 0.1 mg/kg IV divided into equal doses at 2–3 min intervals
- Verapamil:
- 2.5–5 mg IV bolus over 2 min; may repeat with 5–10 mg q15–30min to max. of 20 mg
- 120–300 mg PO daily
- 2.5–5 mg IV bolus over 2 min; may repeat with 5–10 mg q15–30min to max. of 20 mg
- Amiodarone:
- 5–7 mg/kg over 30–60 min, then 1.2–1.8 g/d continuous infusion or in divided PO doses until 10 g total
- 600–800 mg/d divided dose until 10 g total, then 200–400 mg/d maintenance
- 5–7 mg/kg over 30–60 min, then 1.2–1.8 g/d continuous infusion or in divided PO doses until 10 g total
- Procainamide: 15–18 mg/kg loading dose administered as a slow infusion over 30 min. Max.: 1 g. Then 2–6 mg/min infusion.
- Quinidine gluconate: 324–648 mg PO q8–12h: (extended release tabs)
- Ibutilide: 1 mg IV for patients >60 kg; 0.01 mg/kg IV for patients <60 kg infused over 10 min; can be repeated once if sinus rhythm not restored within 10 min. Requires normal QTc, no history of torsades, no hypokalemia. Patients must be monitored for 4 h for QT prolongation, Torsades de Pointes, and ventricular tachycardia.
- Flecainide: 2 mg/kg IV at 10 mg/min PO. Do not give in patients with structural heart disease.
- Propafenone: 1–2 mg/kg IV at 10 mg/min
- Sotalol: 75 mg infused IV over 5 h BID if CrCl >60 mL/min. Give QD if CrCl 40–60 mL/min
- Heparin: Load 80 U/kg IV; infusion at 18 U/kg/h. Dosage adjustment required in obese patients
- Low-molecular-weight heparin: 1 mg/kg SQ BID
- Warfarin sodium: 2.5–5 mg/d PO, dosage adjustments based on INR
- Aspirin: 50–325 mg/d
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