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
Giant a waves in JVP is seen in: 
Select and explain. 
A. Tachycardia, B. Atrial ectopic, C. 1st degree heart block, D. Complete heart block
D: Complete heart block
Answer: D: Complete heart block 
Explanation: Ans: dRef: Harrison, 16thed, p. 1306