ECG library
Third-degree (complete) AV block
advancedAn 81-year-old with syncope on the stairs.
25 mm/s · 10 mm/mV · synthetic tracing
100%
Calipers:2000 ms50.0 small boxes30 bpm if R-RDrag the orange markers. One small box = 40 ms.
Key findings
- More Ps than QRSs
- No fixed PR
- Slow wide escape rhythm
Learning points
- Map every P with calipers; complete block reveals itself when Ps keep perfect time and ignore the QRS.
- The width of the escape estimates its origin: narrow junctional escapes are more stable than wide ventricular ones.
Connected