Sometimes in a simple 1-lead ECG strip, various interesting ECG phenomena can be recognized, such as here.
One could briefly look over the ECG, make the diagnosis of ventricular bigeminus and then be satisfied.
On closer inspection, however, 3 questions arise:
1. Is the P wave behind the PVC a sinus node P or an atrial extrasystole?
2. + 3. after one comes to the conclusion that it is a sinus node P: why is it not conducted and why is the PP distance smaller when there is a QRS complex in between than when there is not.