Temporary Pacing in Bradycardia
Temporary transvenous pacing is reasonable in patients with persistent hemodynamically unstable bradycardia refractory to medical therapy until a permanent pacemaker is placed or the bradycardia resolves. 1
Clinical Assessment Framework
Determine hemodynamic stability first by assessing for signs of poor perfusion: altered mental status, ischemic chest discomfort, acute heart failure, hypotension (systolic BP <80 mmHg), or shock. 2, 3 Document the rhythm with 12-lead ECG and establish continuous cardiac monitoring while obtaining IV access. 2
Treatment Algorithm
First-Line Medical Therapy
- Atropine 0.5-1 mg IV is the initial treatment, repeated every 3-5 minutes to a maximum total dose of 3 mg. 1, 2, 3
- Doses <0.5 mg may paradoxically slow heart rate further and should be avoided. 3
- Atropine is likely effective for sinus bradycardia and AV nodal block, but ineffective for type II second-degree or third-degree AV block with wide QRS. 3
Second-Line Options When Atropine Fails
- Dopamine 5-10 mcg/kg/min IV or epinephrine 2-10 mcg/min IV for chronotropic and inotropic support. 1, 2, 3
- Transcutaneous pacing (TCP) should be initiated immediately in unstable patients unresponsive to atropine as a bridge to definitive therapy. 1, 2, 3
Indications for Temporary Pacing
Class IIa (Reasonable)
Temporary transvenous pacing is reasonable for:
- Persistent hemodynamically unstable sinus node dysfunction or AV block refractory to medical therapy until permanent pacemaker placement or resolution. 1
- Complication rates range from 14-40%, including lead dislodgement (16%), venous thrombosis, and infection risk. 1, 4
Class IIb (May Be Considered)
Temporary transcutaneous pacing may be considered for:
- Severe symptoms or hemodynamic compromise as a bridge to transvenous or permanent pacing. 1
- Most patients require 40-80 mA current; higher thresholds occur with emphysema, pericardial effusion, or positive pressure ventilation. 5
- Requires adequate sedation/analgesia due to pain in conscious patients. 3, 5
Class III: Harm (Should NOT Be Performed)
Temporary pacing should NOT be performed in:
- Patients with minimal and/or infrequent symptoms without hemodynamic compromise. 1
- Asymptomatic bradycardia, sleep-related bradycardia, or physiologic sinus bradycardia in athletes. 1, 2, 6
- Asymptomatic sinus pauses secondary to elevated parasympathetic tone. 1, 2
Special Clinical Scenarios
Post-Cardiac Transplant
- Avoid atropine due to denervation—may cause paradoxical high-degree AV block. 1, 3
- Use aminophylline/theophylline or epinephrine instead. 1, 3
Acute Spinal Cord Injury
- Bradycardia often refractory to atropine due to unopposed parasympathetic stimulation. 1, 2
- Aminophylline or theophylline targets underlying pathology and can avoid permanent pacemaker. 1
Acute Myocardial Infarction
- Use caution with rate-accelerating drugs—may worsen ischemia or increase infarct size. 1, 3
- Inferior MI with AV block may respond to atropine or aminophylline. 1
Critical Pitfalls to Avoid
- Do not delay TCP while giving additional atropine doses in unstable patients—TCP should be initiated immediately when atropine fails. 6, 3
- Lead dislodgement occurs in 16% of temporary transvenous pacing cases, with 50% within first 24 hours—requires continuous monitoring. 6
- Infection risk increases with temporary pacing wire before permanent implant—remove or replace as soon as clinically feasible (typically 2-19 days). 1, 6
- TCP is ineffective when applied >27-90 minutes after arrest onset—early application is critical. 7
Real-World Outcomes
In emergency department cohorts, approximately 20% of patients with compromising bradycardia required temporary pacing for initial stabilization, and 50% ultimately needed permanent pacemakers. 8 Mortality at 30 days was 5%, with serious complications occurring in 22% of cases. 4, 8