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!

Further Reading

• Wiesbauer F, Kühn P. ECG Mastery: Yellow Belt online course. Understand ECG basics. Medmastery
• Wiesbauer F, Kühn P. ECG Mastery: Blue Belt online course: Become an ECG expert. Medmastery
• Kühn P, Houghton A. ECG Mastery: Black Belt Workshop. Advanced ECG interpretation. Medmastery
• Rawshani A. Clinical ECG Interpretation ECG Waves
• Smith SW. Dr Smith’s ECG blog.
• Wiesbauer F. Little Black Book of ECG Secrets. Medmastery PDF