This rhythm strip was taken from a 41-year-old male with lymphoma. He had a 5-day history of substernal chest pain, which was increased by lying down and decreased by sitting up and leaning forward.

We have had several cases in which the presenting rhythm was either unavailable or not communicated to hospital providers. In one case, a 25-year-old patient with a reported pulseless, wide-complex ...

The basic rhythm is sinus. Many premature beats are present, which are all preceded by prematurely occurring P waves (marked by x) and are all PACs. The premature P waves shown in Figure 2 are all ...