Electrophysiology

A 69-year-old man who is in the ER with palpitations. His past medical history is not immediately available. Physical exam is otherwise unremarkable.  What is going on? 

This is a tracing from an ambulatory monitor on an elderly lady with palpitations. Although its interpretation is straightforward, the tracing demonstrates several electrophysiological phenomena that are basic for understanding EKG interpretation.What are these phenomena?Try to choose the correct answer from the poll below, then you can review the attached 5 min video for the answer and explanation.

This tracing was taken from a 68 year-old-female with h/o palpitations. Her EKG showed NSR with PVCs in a trigemini pattern.Again, this tracing demonstrates a basic electrophysiological phenomenon, what is it?Answer the question in the poll before before viewing the video with the explanation