Acute Management of Arrhythmias - Mark Sonderman

  • Have RN prepare 12-lead EKG while walking to room, and place defib pads on patient
  • Is the patient unstable (hypotensive, signs/symptoms of hypoperfusion)?
  • Is the information real?
    • Review tele strips if stable: VUMC Web Resources à VUH PIICiX Philips Web à patient selection à alarm review (
    • Review past EKGs to determine if patient has had this rhythm before
  • IV access?
  • Draw labs: BMP, Mg, TSH, and +/- troponin, tox screen




  • Sinus bradycardia, Sick Sinus Syndrome
    • Consider underlying etiology and treat appropriately
    • Sepsis/hypoxia/vagal tone/ overmedication (beta-blockers, non-DHP CCB)
    • Unlikely to cause symptoms if HR > 50
  • AV Block
    • First degree: PR interval >200 ms
    • Second degree AV block (Mobitz I): progressively prolonging PR followed by non-conducted P wave
    • Second degree AV block (Mobitz II): dropped beats without prolonging PR
    • Third degree AV block (complete heart block): no association between P and QRS



  • Avoid nodal blocking agents
  • Consider reversible causes of new heart block –acute MI (especially inferior), metabolic derangement (especially hyperkalemia), endocarditis with abscess, medication related
  • In Mobitz II or Complete heart block, EP consult for pacemaker evaluation
  • If unstable, General Schema for symptomatic (hypotensive) bradycardia:

Atropine (0.5 mg every 3 to 5 minutes; maximum total dose: 3 mg)


Call CCU Fellow


Dopamine (2 to 20 mcg/kg/minute)


Transvenous pacing


(Pacer pads on the defib device are capable of pacing, but don’t forget to sedate!)

Schema for arrhythmia



Tachyarrhythmia - Narrow complex

  • For any unstable tachyarrhythmia, start with treatment (synchronized cardioversion or ACLS) and determine type later; Consider 0.5-2 mg IV midazolam for sedation
  • Place defibrillator pads, prepare for synchronized cardioversion at 200 J (can 300-360 J)



  • Sinus tachycardia
    • Address underlying causes: fever/sepsis, hypo/hypervolemia, anxiety, anemia, PE, ACS, hypoxia, pain, urinary retention, withdrawal
  • Atrial Fibrillation/Flutter – See AFib section for complete details
  • AVNRT/Orthodromic AVRT
    • Vagal maneuvers are first line
      • Pt sits upright, give pt 10cc syringe and have them blow into tip for 10-15 sec, once they are done, have them rapidly lay supine and raise legs
    • Adenosine
      • Therapeutic to break AVRT/AVNRT and diagnostic, as it causes transient AV block that may allow visualization of atrial tachycardia or flutter
      • Do NOT give with Heart transplant, severe COPD, pre-excitation causing wide complex tachycardia (WPW à antidromic AVRT)
      • Warn pt, he or she will transiently feel terrible
        • 6mg x1 à 6mg x1 (if not effective after 1-2 min) à 12mg x1 (if refractory to 6mg)
        • Given peripherally at AC site or above w/ arm elevated then flush rapidly
        • If giving centrally, cut dose in half: 3mg x1 à  3mg x1 à  6mg
  • Multifocal atrial tachycardia: irregularly irregular, > 3 p wave morphologies/PR intervals
    • Seen in pulmonary and cardiac disease
    • Does not cause hemodynamic instability
    • BBs and non-DHP CCBs can be effective, need to address underlying issue





Side Effects


5mg IV q5m x3

PO metoprolol tartrate 12.5mg q6 hours  every 6 hr to target

Good 1st line agent

Less BP effect than dilt


Negative inotropy


10-20 mg IV over 2m q15m x2

drip = 5-15 mg/hr

Good 1st line w/ normal EF with drip needed


Avoid in HFrEF


500 mcg/kg bolus

drip = 50-200 mcg/kg/min

Rapid onset/offset

RBC metabolism




150 IV over 10-30m, then 1 mg/m for 6h, then 0.5mg/m for 18h

Minimal BP effects

Long lasting; Relatively fast onset (acute effect is mostly beta blockade)

Pulmonary and thyroid toxicity



500mcg IV x1, then 250mcg IV q6h x2-3

Great for reduced EF, positive inotropy

Slow onset

Depends on vagal tone – poor in hyper- adrenergic states


20-50 mg/min loading, 1-4 mg/min maintenance

Use in pre-excitation syndromes (ie WPW), does not inhibit AV nodal conduction