The Cardiac Cycle and Pressure–Volume Loops: A Systematic Approach

Which of the following correctly lists the four chambers of the heart?

A patient has a heart rate of 80 beats per minute and a stroke volume of 70 mL per beat. Calculate the cardiac output in liters per minute. Fill in the blank: Cardiac output = ____ L/min.

Explain the role of calcium in cardiac muscle contraction and relaxation.

Arrange the components of the cardiac conduction pathway in the correct order from the initiation of the electrical impulse to ventricular activation.

1. SA node
2. AV node
3. Bundle of His
4. Purkinje fibers
5. Atria

Match each ECG wave to the corresponding cardiac event.

Describe the process of calcium-induced calcium release in cardiac muscle.

Identify the phases of the cardiac cycle during which all four heart valves are closed and explain why ventricular volume remains constant during these phases.

A patient has an end-diastolic volume (EDV) of 130 mL and an end-systolic volume (ESV) of 55 mL. Calculate the stroke volume in mL. Fill in the blank: Stroke volume = ____ mL.

Which heart sound is produced by the closure of the atrioventricular valves?

Using the Wiggers diagram, explain which electrical event immediately precedes isovolumetric contraction and how this electrical event leads to the mechanical event.

In a pressure-volume loop, the loop is traversed in which direction?

Match each phase of the cardiac cycle to the corresponding segment of the PV loop.

A patient has an end-diastolic volume (EDV) of 150 mL and an end-systolic volume (ESV) of 60 mL. Calculate the ejection fraction as a percentage. Fill in the blank: Ejection fraction = ____%.

Given a PV loop with an end-diastolic volume (EDV) of 140 mL and an end-systolic volume (ESV) of 50 mL, identify EDV and ESV on the loop and calculate the stroke volume.

Define preload, afterload, and contractility in terms of PV loop parameters.

If preload is increased while afterload and contractility remain constant, what is the expected effect on the PV loop and stroke volume?

Compare the effects of increased afterload and increased contractility on the PV loop and stroke volume.

In systolic heart failure, which PV loop change is expected?

Differentiate the PV loop changes in aortic stenosis versus mitral regurgitation.