A 69-year-old woman is admitted to the CCU with unstable angina:

• Accelerated junctional rhythm, 84/min
• Non-specific ST abnormality

Comment: One can see retrograde P-waves which are the result of “backwards” activation over the AV node (the junction fires, and electrical activation goes back up the AV node creating a p-wave which is negative in the inferior leads because atrial activation is now superiorly directed)