Definition of Symptomatic Bradycardia
Symptomatic bradycardia is defined as a documented bradyarrhythmia that directly causes clinical manifestations such as syncope, presyncope, transient dizziness, lightheadedness, heart failure symptoms, or confusional states resulting from cerebral hypoperfusion attributable to slow heart rate. 1, 2
Key Characteristics
- Bradycardia is generally defined as a heart rate below 60 beats per minute, but when bradycardia is the cause of symptoms, the rate is typically less than 50 beats per minute 1
- A slow heart rate may be physiologically normal for some patients, while a heart rate >50 beats per minute may be inadequate for others, highlighting the importance of clinical correlation 1, 2
- The Bradycardia Algorithm focuses on management of clinically significant bradycardia (i.e., bradycardia that is inappropriate for the clinical condition) 1
Clinical Manifestations
- Major symptoms that indicate symptomatic bradycardia include: 2, 3
- Syncope or near-syncope
- Dizziness or lightheadedness
- Chest pain/angina
- Dyspnea or heart failure symptoms
- Confusion or altered mental status due to cerebral hypoperfusion
Types of Symptomatic Bradycardia
- Symptomatic bradycardia can be broadly classified into two general categories: 2
- Sinus node dysfunction (SND)
- Atrioventricular (AV) block
Important Clinical Considerations
- The mere presence of bradycardia without associated symptoms almost never justifies aggressive intervention, with few exceptions 3
- Intervention is warranted only when bradycardia is symptomatic or likely to progress to a life-threatening condition 2
- In the acute setting, determining if bradycardia is the cause of the patient's symptoms is critical 4
- Approximately 20% of patients presenting with compromising bradycardia require temporary emergency pacing for initial stabilization 5
Common Pitfalls to Avoid
- Treating asymptomatic bradycardia unnecessarily 2
- Failing to recognize that symptoms may be subtle or intermittent 1
- Not considering potentially reversible causes (medications, electrolyte disorders, acute myocardial infarction) before permanent pacemaker implantation 3, 5
- Using arbitrary heart rate cutoffs without clinical correlation to determine treatment 6
Management Approach
- Management is based on the severity of symptoms, underlying causes, presence of potentially reversible causes, presence of adverse signs, and risk of progression to asystole 7
- In the acute setting, symptomatic patients should be treated with atropine 4
- Percutaneous pacing can be used as a bridge to definitive treatment 4
- The only definitive therapy for persistent symptomatic bradycardia is placement of a permanent pacemaker 4