The P-waves and P–R intervals are variable due to a phenomenon called wandering<unk>  pacemaker (WAP). The electrical impulse is generated at a different focus within the<unk> of the heart each time. WAP is positive once the heart generates at least three different P-wave formations from the same ECG lead. Then, if the heart rate exceeds 100 beats per minute, the phenomenon is called<unk> .
Multifocal atrial tachycardia
Wandering atrial pacemaker
Atrioventricular reentrant tachycardia
AV nodal reentrant tachycardia
Second-degree atrioventricular block
Third-degree atrioventricular block
First-degree atrioventricular block
Sinus arrhythmia