For which patient is temporary cardiac pacing relatively contraindicated in the emergency department?

Temporary Cardiac Pacing Relative Contraindication

The complete heart block patient who is asymptomatic with HR 35 bpm and BP 92/60 mm Hg represents a relative contraindication to temporary pacing, as temporary pacing should not be performed in patients with minimal or infrequent symptoms without hemodynamic compromise. 1, 2

Clinical Reasoning by Patient Scenario

Patient 1: Beta-blocker Overdose (HR 28, BP 62/30)

• This patient demonstrates clear hemodynamic instability with profound hypotension and severe bradycardia 1
• Temporary pacing is strongly indicated for persistent hemodynamically unstable bradycardia refractory to medical therapy 1, 3
• The combination of low heart rate, hypotension, and likely signs of shock (poor perfusion) makes this an urgent indication for pacing 4, 5

Patient 2: Complete Heart Block, Asymptomatic (HR 35, BP 92/60) - THE ANSWER

• This is the relative contraindication - the patient lacks hemodynamic compromise despite complete heart block 1, 2
• Blood pressure of 92/60 mm Hg, while low-normal, does not constitute shock or severe hypotension 1
• The American College of Cardiology explicitly recommends against temporary pacing (Class III: Harm) in patients with minimal or infrequent symptoms without hemodynamic compromise 1, 2
• Asymptomatic bradycardia should never be paced, even with complete heart block, if the patient remains hemodynamically stable 2
• The risks of temporary pacing (infection, lead dislodgement in 16% of cases, arrhythmia induction during catheter manipulation) outweigh benefits in stable patients 4, 2

Patient 3: Polymorphic VT Unresponsive to Medical Therapy

• Temporary pacing is indicated for life-threatening ventricular arrhythmias mediated by bradycardia 1
• Polymorphic VT often requires overdrive pacing for termination when refractory to medications 6
• This represents a clear indication, not a contraindication 1

Patient 4: Second-Degree Type II Block with Chest Pain (HR 35, BP 92/60)

• Temporary pacing is strongly indicated - second-degree AV block complicating anterior MI warrants temporary pacing 1
• The severe chest pain suggests acute myocardial infarction, and Type II block in this context has high risk of progression to complete heart block 1
• His-Purkinje disease from anterior infarction will not respond to atropine and requires pacing support 4

Key Contraindication Principles

Relative contraindications to temporary transvenous pacing include: 4

• Central venous cannulation is risky (e.g., soon after thrombolysis)
• Operator inexperience
• Sick patient would need to be moved to perform the procedure
• Unstable patients more likely to develop serious arrhythmias from electrode passage and positioning

Critical Pitfall to Avoid

The most common error is confusing bradycardia presence with bradycardia indication for pacing 1, 2. The decision hinges on:

• Presence of symptoms (syncope, altered mental status, chest pain, dyspnea) 5
• Hemodynamic compromise (hypotension causing shock, poor perfusion, low urine output) 4, 5
• Not simply the heart rate number or ECG rhythm alone 1, 2

In the asymptomatic complete heart block patient, observation and preparation for potential pacing is appropriate, but immediate transvenous pacing insertion carries more risk than benefit 1, 2.