the cardiac cycle is 10 seconds long assuming the heart beats 75 times per minute.
the cardiac cycle is 10 seconds long assuming the heart beats 75 times per minute.
how long is the cardiac cycle assuming the heart beats 75 times per minute?
10 seconds
the cardiac cycle is the performance of the human heart from the ending of one heartbeat to the beginning of the next. it consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole (), followed by a period of robust contraction and pumping of blood, dubbed systole (). after emptying, the heart immediately relaxes and expands to receive another influx of blood "returning from" the lungs and other systems of the body, before again contracting to "pump blood to" the lungs and those systems. a normally performing heart must be fully expanded before it can efficiently pump again. assuming a healthy heart and a typical rate of 70 to 75 beats per minute, each cardiac cycle, or heartbeat, takes about 0.8 seconds to complete the cycle.
cardiac cycle
velocity-encoded mri is based on the detection of changes in the phase of proton precession. these changes are proportional to the velocity of the protons' movement through a magnetic field with a known gradient. when using velocity-encoded mri, the result is two sets of images, one for each time point in the cardiac cycle. one is an anatomical image and the other is an image in which the signal intensity in each pixel is directly proportional to the through-plane velocity. the average velocity in a vessel, i.e., the aorta or the pulmonary artery, is quantified by measuring the average signal intensity of the pixels in the cross-section of the vessel then multiplying by a known constant. the flow is calculated by multiplying the mean velocity by the cross-sectional area of the vessel. this flow data can be used in a flow-versus-time graph. the area under the flow-versus-time curve for one cardiac cycle is the stroke volume. the length of the cardiac cycle is known and determines heart rate; "q" can be calculated using equation (). mri is typically used to quantify the flow over one cardiac cycle as the average of several heart beats. it is also possible to quantify the stroke volume in real-time on a beat-for-beat basis.
cardiac output