What is the next step for a 35-year-old female who complains of chest pain (CP) and shortness of breath (SOB) with running, with an electrocardiogram (EKG) showing bradycardia and sinus arrhythmia?

Management of Chest Pain and Shortness of Breath with Exercise in a 35-Year-Old Female with Bradycardia and Sinus Arrhythmia

For a 35-year-old female with chest pain and shortness of breath during running who has bradycardia (HR 58) and sinus arrhythmia on ECG, an exercise treadmill test is the most appropriate next step to determine if permanent pacing is needed.

Initial Assessment of Bradycardia and Symptoms

• The patient's presentation includes exertional symptoms (chest pain and shortness of breath) with evidence of bradycardia (heart rate of 58) and sinus arrhythmia on ECG 1
• Sinus bradycardia alone should not be used for the diagnosis of sinus node dysfunction; multiple factors must be considered for the individual patient 1
• Bradycardia with heart rate of 58 bpm is relatively mild and may be physiological, especially if the patient is physically active 2
• Sinus arrhythmia is often a normal variant, particularly in younger individuals and athletes 2

Correlation Between Symptoms and Bradycardia

• The key clinical question is whether the patient's exertional symptoms (chest pain and shortness of breath) are related to the bradycardia or have another cause 1
• In patients with exertional symptoms who have bradycardia at rest, an exercise treadmill test is reasonable to determine whether they may benefit from permanent pacing (Class IIa recommendation, Level of Evidence: C-LD) 1
• Exercise testing can help establish if there is chronotropic incompetence (inability to increase heart rate appropriately with exercise) 2
• Chronotropic incompetence represents failure to reach a target heart rate with exertion that is inadequate to meet metabolic demand 1

Diagnostic Algorithm for Exertional Chest Pain with Bradycardia

1. Exercise treadmill test (first-line)

   • Evaluates heart rate response to exercise 1
   • Can identify exercise-induced ischemia 1, 3
   • Determines correlation between symptoms and rhythm abnormalities 1

2. If exercise test is non-diagnostic or unavailable:

   • Ambulatory electrocardiographic monitoring (Holter) to establish correlation between symptoms and rhythm abnormalities (Class IIa recommendation, Level of Evidence: B-R) 1
   • Consider echocardiography to evaluate for structural heart disease 1

3. If significant bradycardia or conduction abnormalities are identified during exercise:

   • Consider electrophysiology study (EPS) to determine the level of block and whether permanent pacing would be beneficial (Class IIb recommendation, Level of Evidence: B-NR) 1

Important Clinical Considerations

• Chest pain with exertion requires careful evaluation to rule out coronary artery disease, which becomes more prevalent in individuals over 35 years 1, 4
• A normal ECG does not exclude significant cardiac disease; 1-4% of patients with normal ECGs who present with chest pain may still have acute myocardial infarction 5
• Immediate exercise testing has been shown to be safe and effective in evaluating low-risk patients with chest pain 3
• Non-cardiac causes of chest pain and shortness of breath should also be considered, including pulmonary conditions like pneumothorax 6

Indications for Permanent Pacing

• Permanent pacing is NOT indicated for asymptomatic sinus bradycardia 1
• Permanent pacing should be considered if:
  • Exercise testing demonstrates chronotropic incompetence correlating with symptoms 1
  • There is evidence of high-grade AV block during exercise 1
  • Symptoms persist and are clearly attributable to bradycardia despite treatment of any underlying cause 1

Clinical Pitfalls to Avoid

• Do not assume all bradycardia in a young active individual requires treatment; physiological bradycardia is common in athletes 2
• Avoid overdiagnosis of pathological bradycardia, which can lead to unnecessary pacemaker implantation 2
• Do not dismiss exertional symptoms without appropriate evaluation, as they may indicate significant cardiac pathology 1
• Avoid relying solely on resting ECG findings, as they have limited diagnostic value in isolation 4, 5