From the Guidelines
A bradycardia workup should begin with a thorough history and physical examination, focusing on symptoms like dizziness, syncope, fatigue, or chest pain, and initial testing should include a 12-lead ECG, basic laboratory tests, and medication review, as recommended by the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
Initial Evaluation
The initial evaluation of bradycardia should include:
- A thorough history and physical examination to identify symptoms and potential causes of bradycardia
- A 12-lead ECG to identify the type of bradycardia (sinus bradycardia, heart block, etc.)
- Basic laboratory tests, such as electrolytes, TSH, and complete blood count, to identify potential underlying causes
- Medication review to identify potential causative agents like beta-blockers, calcium channel blockers, or digoxin
Additional Testing
Additional testing may include:
- Ambulatory monitoring with a Holter monitor (24-48 hours) or event recorder (up to 30 days) for intermittent symptoms
- Echocardiogram to assess structural heart disease
- Exercise stress testing to evaluate chronotropic incompetence
- Electrophysiology studies for patients with concerning symptoms or high-grade conduction abnormalities, as recommended by the 2018 ACC/AHA/HRS guideline 1
Management
Management of bradycardia depends on the cause and may include:
- Addressing reversible factors, such as medication adjustment or treating hypothyroidism
- Observation for asymptomatic patients with sinus bradycardia
- Pacemaker implantation for symptomatic bradycardia, advanced heart block, or sinus node dysfunction, as recommended by the 2018 ACC/AHA/HRS guideline 1
Treatment of Symptomatic Bradycardia
The treatment of symptomatic bradycardia may include the use of atropine, isoproterenol, dopamine, or epinephrine, as recommended by the 2018 ACC/AHA/HRS guideline 1. Atropine is the first-line treatment for symptomatic bradycardia, with a recommended dose of 0.5 to 1 mg IV repeated every 3 to 5 minutes as needed, up to a maximum total dose of 3 mg 1.
From the Research
Diagnosis and Evaluation of Bradycardia
The workup for bradycardia involves a thorough history and physical examination to identify possible causes of sinoatrial node dysfunction or atrioventricular (AV) block 2. The diagnosis is generally established by noninvasive diagnostic studies, including:
- 12-lead electrocardiogram
- Holter electrocardiogram
- Exercise testing
- Event recorder
- Implantable loop recorder 3 Invasive electrophysiologic testing is rarely required.
Symptoms and Presentation
Bradycardia can present with a range of symptoms, including:
- Syncope or near-syncope
- Dizziness or fatigue
- Chest pain or dyspnea
- Heart failure symptoms
- Nonspecific and chronic symptoms such as dizziness or fatigue 3, 4 Asymptomatic bradycardia is common, especially among trained athletes or during sleep 4.
Management and Treatment
The management of bradycardia is based on the severity of symptoms, the underlying causes, and the presence of potentially reversible causes 2. Treatment options include:
- Pharmacologic therapy, such as atropine, to increase heart rate 4
- Temporary or permanent pacing, including percutaneous pacing or implantable pacemakers 4, 5
- Treatment of underlying conditions, such as metabolic or ischemic disorders, or adverse drug reactions 6 In symptomatic patients, placement of a permanent pacemaker is often the therapy of choice 3, 4, 5.