P wave is absent in-
Absence of the P wave with a flat baseline may indicate: Fine atrial fibrillation Sinoatrial arrest (with a secondary escape rhythm ) in ventricular fibrilation ,ventriculat tachycardia and atrial asystole,a waves are present Ref Harrison 20th edition pg 1423
Atrial fibrillation
Atrial asystole
Ventricular fibrillation
Ventricular tachycardia
C.V.S