In this setting, the atrial rate (P waves) and ventricular rate (QRS complexes) are at different heart rates. One quick and easy way to measure the ventricular rate is to examine the RR interval ...

Idioventricular rhythms meet criteria for ventricular tachycardia, but have a heart rate of < 100. Massive left atrial enlargement causes a notch in the P wave and is termed “P-mitrale.” ...