A | Is the beginning of electromechanical systole. It is associated with the atrial contraction. |
B | Appears simultaneously with the opening of the aortic valve. The precise identification of a B point is important for accurate calculation of stroke volume and cardiac output [33]. It denotes the beginning of the ejection time. It has been reported that the marker of this point is not always apparent [34] and it may occur at any point on the ascending portion of the signal before the (dZ/dt) max [35, 36]. |
C | Is taken at the peak of the ICG signal and it corresponds to the ventricular contraction. The amplitude of this point is used to calculate the stroke volume and cardiac output. |
X | Is the lowest point after the peak and it is associated with the closure of the aortic valve. It indicates the end of the systole [37]. |
O | Is associated with changing of the volume during the diastolic phase of the cycle and the maximal opening of the mitral valve [37]. |