Overview
Definition
A collection of heart rhythm disorders that include sinus bradycardia, sinus pauses, and tachy-brady syndrome, caused by SA node dysfunction.
Epidemiology
Primarily affects the elderly due to age-related degeneration of the SA node.
Etiology & Risk Factors
- Idiopathic fibrosis and calcification of the SA node
- Ischemia (RCA occlusion)
- Medications (Beta-blockers, CCBs, Digoxin)
Clinical Symptoms
- Syncope / Pre-syncope
- Fatigue
- Dizziness
- Palpitations (during tachycardia phases)
Clinical Approach
Diagnosis
- ECG or Holter Monitor: Alternating periods of profound sinus bradycardia, sinus pauses (>3 seconds), and episodes of atrial tachyarrhythmias (Tachy-Brady syndrome)
Management
- Discontinue offending medications
- Permanent Pacemaker (PPM) placement for symptomatic bradycardia
- Once pacemaker is in place, rate-controlling meds can be safely used for the tachycardia phases
Complications
- Syncope leading to traumatic falls
- Heart failure