Sinus Node Dysfunction

What is Sinus Node Dysfunction?

Sinus node dysfunction (also known as sick sinus syndrome) is a condition in which the heart beats slower than normal. Typically, this is caused by a defect in the heart electrical system. If the heart rate is persistently slow and causing significant symptoms, a pacemaker may be required. Some patients may experience a slow heart rate as well as a rapid heart rate in bursts, a condition known as tachycardia-bradyacrdia syndrome (or tachy-brady syndrome).

Risk Factors

  • Hypertension
  • Coronary artery disease 
  • Mitral regurgitation 
  • Tricuspid regurgitation 
  • Heart failure 


  • Sensation of heart racing or skipped heartbeats 
  • Chest tightness or discomfort
  • Lightheadedness or dizziness
  • Fainting or near fainting spells 
  • Shortness of breath 

Diagnosis and Tests

  • Electrocardiogram 
  • 24-hour Holter monitor
  • 30-day event monitor 
  • Echocardiogram 
  • Stress test


  • Avoidance of medications that slow heart rate
  • Permanent pacemaker implantation