What is the management for a cardiac pause?

Management of Cardiac Pause

For symptomatic cardiac pauses, initial management includes atropine 0.5 mg IV (up to 3 mg total) followed by temporary pacing if bradycardia persists, with permanent pacing indicated for recurrent symptomatic pauses not due to reversible causes. 1, 2

Initial Assessment and Management

Immediate Management of Symptomatic Cardiac Pause

• First-line treatment: Atropine 0.5 mg IV every 3-5 minutes (maximum total dose 3 mg) 1, 3
• If atropine ineffective: Initiate infusion of epinephrine (2-10 μg/min) or dopamine (2-10 μg/kg/min) 3
• For persistent symptomatic bradycardia: Implement transcutaneous pacing 2, 3
• For specific causes:
  • Calcium channel blocker overdose: Calcium (10% calcium chloride 1-2g IV) 3
  • Beta-blocker overdose: Glucagon (3-10mg IV with infusion of 3-5mg/h) 3
  • Inferior MI with bradycardia unresponsive to atropine: Consider theophylline (100-200 mg slow IV) 3

Temporary Transvenous Pacing

• Indication: Reasonable for persistent hemodynamically unstable bradycardia refractory to medical therapy 2
• Class IIa recommendation (Level C-LD): For patients with persistent hemodynamically unstable sinus node dysfunction refractory to medical therapy 2
• Note: Temporary pacing carries complication rates of 14-40% and should be used judiciously 2

Management Based on Cause

Reversible Causes

• First step: Identify and treat reversible causes before considering permanent interventions 2, 3
• Common reversible causes:
  • Medications (beta-blockers, calcium channel blockers, digoxin)
  • Electrolyte abnormalities
  • Hypothyroidism
  • Increased vagal tone 3

Intrinsic Causes

• For intrinsic AV block: Symptom-rhythm correlation is less important as there is consensus that pacing prevents recurrence of syncope 2
• For sinus node dysfunction: Correlation between symptoms and bradycardia is crucial before considering permanent pacing 2

Criteria for Permanent Pacing

Indications for Permanent Pacemaker

• Class I recommendation:

  • Sinus node disease with documented symptomatic bradycardia due to sinus arrest or sinus-atrial block 2
  • Intermittent/paroxysmal intrinsic third- or second-degree AV block 2

• Class IIa recommendation:

  • Patients ≥40 years with syncopes and documented symptomatic pauses due to sinus arrest or AV block 2
  • Patients with history of syncope and asymptomatic pauses >6 seconds 2

Contraindications for Permanent Pacing

• Class III (Harm) recommendation:
  • Asymptomatic sinus bradycardia or pauses due to physiologically elevated parasympathetic tone 2
  • Sleep-related sinus bradycardia or transient sinus pauses during sleep 2
  • Asymptomatic SND or symptoms documented to occur in absence of bradycardia 2
  • Reversible causes of bradycardia 2

Special Considerations

Impact of Pauses on Survival

• Prolonged pauses during cardiac arrest resuscitation are associated with decreased survival 4, 5, 6
• Minimizing peri-shock pauses during CPR is critical - pre-shock pauses <10s and peri-shock pauses <20s are associated with higher odds of survival 5

Asymptomatic Pauses

• Ventricular pauses ≥3 seconds are uncommon (0.8% of patients) and usually do not cause symptoms 7
• Asymptomatic pauses do not necessarily require pacing - a study showed similar 3-year survival rates between paced and unpaced patients with asymptomatic pauses 7

Clinical Pitfalls to Avoid

• Don't miss reversible causes: Always identify and treat reversible causes before considering permanent pacing 2
• Don't pace physiologic bradycardia: Young individuals and athletes may have resting heart rates below 40 bpm without requiring intervention 2
• Don't ignore symptoms: The presence of symptoms correlating with bradycardia is crucial in decision-making for permanent pacing 2
• Don't delay temporary pacing: For hemodynamically significant bradycardia causing instability, temporary pacing should not be delayed if medical therapy fails 2
• Don't use verapamil for wide-complex tachycardia: If diagnosis is unclear, wide-QRS tachycardia should be presumed to be ventricular tachycardia; calcium channel blockers should not be used 2