What is the initial workup and management for a patient presenting with bradycardia?

Initial Workup and Management for Bradycardia

For patients presenting with bradycardia, the initial workup should include a 12-lead ECG, comprehensive history, physical examination, and cardiac monitoring to establish correlation between symptoms and rhythm, followed by targeted laboratory testing and appropriate management based on symptom severity. 1, 2

Initial Assessment

• Evaluate if heart rate is appropriate for clinical condition (typically <50 beats per minute when symptomatic) 3
• Assess for signs and symptoms of poor perfusion, such as altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or shock 3, 2
• Maintain patent airway and assist breathing as necessary 3
• Provide supplementary oxygen if hypoxemic 3
• Attach cardiac monitor to identify rhythm, monitor blood pressure, and measure oxygen saturation 3
• Establish IV access for potential medication administration 3, 2
• Obtain 12-lead ECG to document rhythm, rate, conduction abnormalities, and screen for structural heart disease 1, 2

Diagnostic Workup

History and Physical Examination

• Obtain detailed information about symptoms including frequency, timing, duration, severity, circumstances, triggers, and alleviating factors 2
• Perform thorough review of all prescription and over-the-counter medications 2
• Evaluate for signs of bradycardia and underlying structural heart disease 2

Diagnostic Testing

• Cardiac rhythm monitoring should be selected based on frequency and nature of symptoms 1, 2
  • Holter monitor for symptoms occurring within 24-72 hours 1
  • Event monitor for less frequent symptoms 1
  • Implantable cardiac monitor for very infrequent symptoms (>30 days between episodes) 1
• Laboratory testing directed toward suspected specific diagnoses:
  • Thyroid function tests 1
  • Electrolyte panel (particularly potassium) 3
  • Lyme titer when clinically suspected 1
  • Drug levels when appropriate 1

Advanced Testing When Initial Evaluation Is Nondiagnostic

• Exercise electrocardiographic testing for suspected chronotropic incompetence or exercise-related symptoms 2
• Electrophysiology study may be considered in selected patients when noninvasive evaluation is nondiagnostic 1
• Screening for sleep apnea in patients with sleep-related bradycardia 1

Management Algorithm

Identify and Treat Reversible Causes

• Medications (beta blockers, calcium channel blockers, digoxin, antiarrhythmics) 3, 4
• Electrolyte abnormalities (hyperkalemia, hypokalemia) 3, 5
• Hypothyroidism 3
• Acute myocardial ischemia or infarction 3
• Increased intracranial pressure 3
• Hypothermia 3
• Infections (including Lyme disease) 3, 2
• Sleep apnea 1, 3

Pharmacologic Management for Symptomatic Bradycardia

• Atropine is first-line therapy for acute symptomatic bradycardia 3, 6
  • Dose: 0.5 mg IV every 3-5 minutes to maximum total dose of 3 mg 3, 6
  • Consider atropine a temporizing measure while awaiting pacemaker placement if needed 3
  • Avoid atropine in heart transplant patients without evidence of autonomic reinnervation 1

When Atropine Is Ineffective or Contraindicated

• Consider IV infusion of β-adrenergic agonists 3, 7
  • Dopamine (particularly if bradycardia is associated with hypotension) 3
  • Epinephrine 3
• Initiate transcutaneous pacing in unstable patients who don't respond to atropine 3, 4

Advanced Management

• Consider expert consultation for complex cases 3
• Prepare for transvenous pacing if temporary measures are ineffective 3, 5
• Consider permanent pacing for chronic symptomatic bradycardia, particularly if caused by necessary medications with no alternatives 3, 8

Important Pitfalls to Avoid

• Don't rely solely on initial ECG for diagnosis, as it provides rhythm correlation with symptoms in only approximately 5% of patients with syncope 2
• Avoid treating asymptomatic or minimally symptomatic patients unless there is suspicion that the rhythm is likely to progress or become life-threatening 2, 9
• Don't delay therapy to obtain diagnostic testing in unstable patients 3
• Recognize that temporary transvenous pacing is associated with higher adverse events compared to early permanent pacemaker implantation in appropriate candidates 5