Are You Tricked by This ECG?

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Figure 1.

Courtesy of Dr Arnel Carmona.

In Figure 1, the R5 and R8 waves have longer PR intervals than the other waves. The R12 and R14 waves have shorter PR intervals than the other waves. The P1 and P2 waves are inverted.

Questions answered incorrectly will be highlighted.

What is happening in Figure 1?

Concealed premature junctional complexes (PJCs) "doing all sorts of tricks"

Two pre-excited beats, two nonconducted premature atrial contractions (PACs), and occasional lengthened PR intervals

Digitalis intoxication