ECG Case 020

Main Abnormalities

• Runs of tachycardia are interspersed with long sinus pauses (up to 6 seconds).
• The sinus rate is extremely slow, varying from 40 bpm down to around 10 bpm in places.
• Sinus beats are followed by paroxysms of junctional tachycardia at around 140 bpm.

Diagnosis

• This is a good example of sick sinus syndrome leading to the tachycardia-bradycardia syndrome.
• The flurries of junctional tachycardia are a compensatory phenomenon attempting to maintain cardiac output in the face of critically low sinus node rates.
• The syncope likely occurred due to a long sinus pause with temporary loss of cardiac output. This patient needs a pacemaker!