Go through the following statements: (i) The stroke volume multiplied by heart rate gives the cardiac output. (ii) The second heart sound is associated with the closure of semilunar valves. (iii) Heart failure is the same as cardiac arrest or a heart attack. Which of these are correct?
(i) & (ii)
Heart attack is the death of heart muscles due to the blockage of a coronary artery. The heart muscles die because it is starved of oxygen (because blood is not getting to it). Heart failure means the heart muscle cannot pump blood around the body properly.