Looking closely at the last part of the QRS complex in leads V1 and V2, P waves can be seen. This is considered a "short RP tachycardia" and is from AVNRT. Adenosine, carotid massage or vagal ...

A combination of the Q wave, R wave and S wave, the “QRS complex” represents ventricular depolarization. This term can be confusing, as not all ECG leads contain all three of these waves ...

These ECG voltage attenuations are of extracardiac mechanism, and impact the amplitude of QRS complexes, P-waves, and T-waves, occasionally resulting also in shortening of the QRS complex and QT ...