Cardiac Physiology: Preload and Afterload Quiz

Which of the following best defines preload in cardiac physiology?

• The resistance the heart must overcome to eject blood during systole.

• The amount of blood returning to the heart (venous return) before contraction.

• The pressure in the arteries after the heart contracts.

• The force the heart needs to push against to circulate blood.

What is afterload most influenced by?

• Venous return, blood volume, and ventricular compliance.

• Systemic vascular resistance (SVR), blood pressure, and aortic valve condition.

• End-diastolic volume (EDV).

• Stroke volume and heart rate.

Which statement correctly describes the effect of increased preload on stroke volume according to the Frank-Starling mechanism?

• Increased preload decreases stroke volume.

• Increased preload has no effect on stroke volume.

• Increased preload increases stroke volume.

• Increased preload causes immediate heart failure.

What can happen if there is too much preload in the heart?

• The myocardium becomes stronger and contracts more efficiently.

• The myocardium becomes overstretched, reducing contractility over time.

• The heart rate decreases significantly.

• The heart valves become more flexible.

Higher afterload has which of the following effects on the heart?

• Makes it easier for the heart to pump.

• Reduces myocardial oxygen demand.

• Leads to higher myocardial oxygen demand and ventricular hypertrophy.

• Decreases the risk of heart failure.

Which condition is NOT a cause of increased preload?

• Fluid overload (kidney failure, IV fluid excess, CHF)

• Valvular regurgitation (mitral/tricuspid)

• Dilated cardiomyopathy

• Systemic vascular resistance

What is a consequence of excess preload in heart failure?

• Increased contractility and improved systolic function.

• Ventricular dilation and weakened contractions.

• Decreased blood volume in the ventricles.

• Reduced risk of pulmonary congestion.

Which of the following best describes the effect of chronic high afterload on the left ventricle?

• It makes the left ventricle work less hard.

• It forces the left ventricle to work harder, leading to heart failure.

• It improves oxygen delivery to the myocardium.

• It reduces ventricular hypertrophy.

Blood backing up into the lungs due to heart failure is most likely to cause which condition?

• Pulmonary and systemic congestion

• Increased contractility

• Decreased preload

• Reduced oxygen demand

Which of the following is a direct effect of increased resistance (afterload) on the heart?

• Lower myocardial oxygen demand

• Higher myocardial oxygen demand

• Reduced ventricular hypertrophy

• Decreased risk of heart failure