This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
For the following cardiac abnormalities, select the characteristic JVP finding.Complete heart block 
Select and explain. 
A. Cannon a wave, B. prominent x descent, C. Kussmaul's sign, D. slow y descent
A: Cannon a wave
Answer: A: Cannon a wave 
Explanation: Large a waves occur with increased resistance to filling (tricuspid stenosis, pulmonary hypertension) or when the right atrium contracts against a tricuspid valve closed by right ventricular systole (Cannon a waves) in complete heart block or other arrhythmias.