You are reviewing a patient that has been woken from sleep by central chest pain, with associated shortness of breath and palpitations. He is a smoker with T1DM and a background of Hypertension and hypercholesterolaemia. His observations are stable and his ECG is below.
- Rate: 78
- Rhythm: see below – regularly irregular
- Axis: Normal 0-90
- Morphology: TWI aVL
- Intervals: PR variable – prolonging from an already long PR interval – easiest to see in Lead II and map on rhythm strip QRS 80 QTc 456
- Summary: 2nd Degree Heart block Type 1 (Mobitz)
Why is this not Complete Heart Block?
To fulfil CHB criteria you must have
- Regular RR interval – X
- Regular p wave –
- AV dissociation – X
- atrial rate > ventricular rate
Criteria for 2nd Degree Heart Block Type 1
- PR prolongation
- Reducing RR interval
- Relation between P and QRS complexes
Patient admitted under cardiology, found to have triple vessel disease requiring CABG.
Further Reading – Textbook:
Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.