'a' wave is absent in
High-Yield Explanation
(A) # 'a' wave of JVP: Due to right atrial contraction Synchronous with carotid artery pulse> Absent 'a' wave: Atrial fibrillation> Diminished 'a' wave: Tachycardia; Prolonged PR interval> 'a' Wave Fused with 'c' Wave: Supra ventricular tachycardia> Large 'a' Waves: Pulmonary hypertension Pulmonary stenosis; Tricuspid stenosis Tricuspid atresia; AV dissociation> Cannon Waves (Giant 'a' Waves): Complete heart block when right atrium occasionally contracts against closed tricuspid valve Ventricular tachycardia; Ectopic beats