Rosen & Barkin's 5-Minute Emergency Medicine Consult (193 page)

DIAGNOSIS

• Felt bad before shock and good after: Likely appropriate therapy
  
• Felt good before and after shock: Likely inappropriate therapy
  
• Felt bad before and after shock: Consider ongoing arrhythmia or ischemia
  
• Appropriate shocks:
  
  • Syncope or near syncope
    
  • Lightheadedness or dizziness
    
  • Shortness of breath
    
  • Palpitations (non-SVT)
    
  • Chest discomfort or pain
    
  • Diaphoresis
    
• Inappropriate shocks:
  
  • Palpitations (SVT)
    
  • No symptoms (Lead-related fractures, inappropriate sensing)
    
• Device infection:
  
  • Fever
    
  • Chills
    
  • Malaise
    
  • Anorexia
    
  • Nausea
    
  • Diaphoresis
    
  • Hypotension
    
  • Heart murmur
    
  • Wound infection:
    
    • Pain
      
    • Erythema
      
    • Purulent drainage
      
    • Warmth
      
    • Fluctuance
      
    • Skin erosion
      
• Hematoma at the insertion site (pocket hematoma):
  
  • Pain (mild)
    
  • Swelling
    
• Vascular (thromboembolic phenomena):
  
  • Unilateral swelling in upper extremity
    
  • Superficial varicosities
    

• Therapy-related:
  
  • Recent angina, heart failure
    
• Device-related:
  
  • Recent implant (<14 days)
    
  • Skin trauma to wound
    
  • Lead-related:
    
    • Repetitive arm motions
      
    • “Twiddler’s syndrome” (inadvertent manipulation of the device)
      
  • Vascular:
    
    • Recent implant
      
    • Multiple leads
      

• Vital signs
  
• Evidence of heart failure/acute coronary syndrome:
  
  • Displaced point of maximal impulse
    
  • Left ventricular heave
    
  • Presence of an S3 or S4
    
  • Presence of basilar rales
    
  • Dullness to percussion
    
  • Determination of jugular venous pressure
    
  • Hepatojugular reflex
    
  • Peripheral edema
    
• Device/site-related:
  
  • Exam of wound/pocket:
    
    • Demarcation of pocket (erythema)
      
    • Purulent drainage
      
  • Exam of affected upper extremity
    

• Following ICD therapy:
  
  • ICD interrogation will determine whether therapy was appropriate and can determine lead fracture if present.
    
  • EKG (transient ST-segment changes and elevations of the cardiac enzymes may be seen after shock delivery and do not necessarily indicate myocardial damage)
    
  • CXR may diagnose lead fracture.
    
• Device/site-related:
  
  • Signs and symptoms of local vs. systemic infection
    
  • Upper-extremity swelling suggests venous thrombosis.
    

• Therapy-related:
  
  • 12-lead EKG
    
  • Cardiac enzymes
    
• Device-related:
  
  • CBC with differential
    
  • Blood cultures
    
  • Do not aspirate pocket
    

• PA and lateral chest radiograph:
  
  • Lead fractures
    
  • Lead dislodgement
    
• Vascular US of upper extremity
  
• MRI absolutely contraindicated:
  
  • Magnetic field may damage ICDs and cause heating at lead tip.
    

• Therapy-related:
  
  • Device interrogation by electrophysiologist/cardiologist
    
  • Application of magnet inhibits tachy therapies (does not affect brady support pacing).
    
• Device/site-related (pocket hematoma/infection):
  
  • Referral to surgeon/electrophysiologist
    
  • Electrocautery should generally be avoided in patients with ICDs unless device is deactivated with programming or with magnet application.
    
• External defibrillation is safe, but avoids shocking directly over ICD (see below).
  

• Appropriate therapies:
  
  • Single shock following an episode of VT or VF with restoration of normal rhythm
    
• Inappropriate therapies:
  
  • Usually due to SVT (afib), lead fracture, or EMI
    
• Phantom shocks:
  
  • Patient awakened from sleep by a perceived shock(s)
    

TREATMENT

Following an ICD electrical discharge:

• IV access
  
• Continuous EKG monitoring
  
• Advanced cardiac life support (ACLS) protocols
  

• ACLS protocols
  
• Magnet application inhibits ICD therapies.
  
• Device-related:
  
  • Pain management
    
  • Elevation of affected extremity (upper-extremity thrombosis)
    

• Patients with devices should receive treatment according to standard ACLS protocols.
  
• Electrical storm may require IV antiarrhythmic agents such as amiodarone.
  
• Inappropriate therapies:
  
  • Treatment of supraventricular dysrhythmia to prevent ICD shocks with β-blockers or calcium channel blockers
    
• Lead-related problems may require further surgical intervention or device reprogramming; magnet application will inhibit tachy therapies.
  
• Device infections:
  
  • Broad-spectrum antibiotics
    
  • Obtain blood cultures 1st
    

• Amiodarone 150 or 300 mg IVP followed by an infusion 1 mg/kg/h for 6 hr, then reduce to 0.5 mg/kg/h. Can rebolus (150 mg) as often as required
  
• Metoprolol: 5 mg IV as needed to control heart rate
  
• Diltiazem: 5–20 mg IV, then a maintenance drip to control heart rate
  
• Cefazolin: 1 g IV q8h
  
• Vancomycin: 1 g IV q12h
  
• Cephalexin: 500 mg PO QID
  
• Warfarin for documented venous occlusion, INR 2–3 for 3 mo
  

FOLLOW-UP

• Therapy-related:
  
  • Ongoing/suspected cardiac ischemia or heart failure
    
  • Multiple ICD shocks and initiation of antiarrhythmic agents for VF/VT or other SVT
    
  • Treat underlying process and consult with electrophysiologist to determine if immediate interrogation is warranted.
    
• Device/site-related:
  
  • Skin erosion
    
  • Wound dehiscence
    
  • Systemic infection/endocarditis
    
  • Need for lead revision
    
  • Expanding pocket hematoma
    
  • Upper-extremity thrombosis
    

• Therapy-related:
  
  • If patient is hemodynamically stable without evidence of active ischemia or heart failure, interrogation usually not required:
    
    • Single-shock, appropriate therapy
      
    • Consult with electrophysiologist and arrange appropriate follow-up.
      
  • Device reprogrammed to avoid inappropriate therapy
    
• Device/site-related:
  
  • Localized infection
    
  • No signs of skin erosion
    
  • Pocket not expanding:
    
    • Prophylactic antibiotics are not indicated for pocket hematomas.
      
  • Wound stable
    

• Therapy-related:
  
  • Cardiologist or electrophysiologist
    
• Device-related:
  
  • Surgeon or cardiologist/electrophysiologist
    

• Aspiration of device pocket is not recommended.
  
• Care should be taken not to deliver external shocks directly over the device, as it may shunt energy away from the heart.
  

• Epstein AE, DiMarco JP, Ellenbogen KA, et al. 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society.
  J Am Coll Cardiol.
  2013;61(3):e6–e75.
  
• Kowalski M, Huizar JF, Kaszala K, et al. Problems with implantable cardiac device therapy.
  Cardiol Clin
  . 2008;26:441–458.
  
• Maron BJ, Spirito P, Shen WK, et al. Implantable cardioverter-defibrillators and prevention of sudden cardiac death in hypertrophic cardiomyopathy.
  JAMA
  . 2007;298:405–412.
  
• Scher DL. Troubleshooting pacemakers and implantable cardioverter-defibrillators.
  Curr Opin Cardiol
  . 2004;19(1):36–46.
  

CODES