Symptoms of sick sinus syndrome (SSS) may develop over a lengthy span of time, even over a period of years. Alternatively, many patients experience no symptoms. Because the symptoms may not seem significant when they occur individually, people may not seek treatment until SSS has reached an advanced stage. Symptoms include:

• Syncope (fainting) spells.
  
  
• Bradycardia (a heart rate that is consistently less than 60 beats per minute).
  
  
• Palpitations (a feeling in the chest of a fast or pounding heartbeat).
  
  
• Angina (chest pain) caused by a lack of blood flow in the heart.
  
  
• Heart failure (new or worsening).
  
  
• Dizziness or lightheadedness.
  
  
• Shortness of breath.
  
  
• Muscle aches.
  
  
• Confusion.
  
  
• Fatigue or unusual tiredness.
  
  
• Disturbed sleep.

In addition to these symptoms, the physician may also be able to detect signs of SSS that may not be noticeable to the patient. Signs of SSS can include various types of arrhythmias (abnormal heart rhythms). These rhythms may be too fast (tachycardia), too slow  (bradycardia) or alternating between fast and slow (brady-tachy syndrome). More than half of patients with SSS experienced brady-tachy syndrome. Specific arrhythmias associated with SSS include:

• Atrial fibrillation. A condition in which the upper chambers of the heart (atria) quiver instead of beat. This is caused by faulty electrical signals in the heart that signal the heart to beat. Atrial fibrillation is a significant risk factor for stroke.
  
  
• Drug-resistant sinus bradycardia. A condition in which the heart beats abnormally slow (less than 60 beats per minute). The sinus bradycardia that is associated with SSS cannot usually controlled with medications.  
  
  
• Sinus pauses. A pause in the signals originating from the sinus node that normally triggers the heartbeat. Sinus pauses are caused by a number of things and are not usually a concern. The pause usually lasts less than three seconds and produces no symptoms. However, when sinus pauses are detected along with other signs, SSS is suspected.
  
  
• Escape rhythms. Any heart rhythm that is produced by signals that do not originate from the sinus node. The sinus node is the heart’s natural pacemaker. If it stops working, the center of the heart (the AV junction) will begin signaling the heart to beat at 40 to 60 beats per minute. This slower pace is called an “escape rhythm.” To a lesser extent, the upper and lower chambers of the heart (atria and ventricles) can also pace the heart.
  
  
• Chronotropic incompetence. Inadequate increase of heart rate during activity which may result in fatigue and exhaustion with exertion. This can be diagnosed by exercise stress test and by observing variation of heart rate during Holter monitoring.