This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Following an attack of myocardial infarction the moality and morbidity of the patient is indicated by 
Select and explain. 
A. Ventricular extra systole, B. Left ventricular ejection fraction, C. Duration of syncope, D. Percentage of narrowness of coronary aery
B: Left ventricular ejection fraction
Answer: B: Left ventricular ejection fraction 
Explanation: Answer is B (Left ventricular ejection fraction) Pump failure is now the primary cause of in hospital death following MI. The degree of pump failure relates well with moality. The most sensitive index of cardiac function amongst the options provided is 'ejection fraction' i.e. the ratio of stroke volume to end diastolic volume. This is thus the best indicator of moality & morbidity following ML