This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
Pulsus alternans is seen in 
Select and explain. 
A. Severe ventricular dysfunction, B. HOCM, C. AS, D. CP
A: Severe ventricular dysfunction
Answer: A: Severe ventricular dysfunction 
Explanation: Pulses alterans is defined by beat-to-beat variability of pulse amplitude.It is seen in patients with severe left ventricular dysfunction and systolic hea failure,and is thought to be due to cyclic changes in intracellular calcium and action potential duration. Hyperophic obstructive cardiomyopathy is characterised by jerky pulse (pulses bisferens). Aoic stenosis is characterised by slow rising carotid pulse.(pulses parvus et tarsus) AS may also have anacrotic pulse Harrison's Medicine-20 the edition.