Cardiac Function and Output Concepts

This lesson covers the basics of hemodynamics, focusing on the cardiac cycle, heart sounds, and EKG tracing. It explains key terms like heart rate, stroke volume, and cardiac output, and discusses the roles of preload, afterload, and contractility. The video also explores methods to influence cardiac output and heart rate, using examples like atropine and vagal maneuvers. The lesson concludes with an analogy comparing hemodynamics to car mechanics, emphasizing the interrelatedness of these factors in maintaining optimal heart function.

What is the primary function of the atrial kick in the cardiac cycle?

• To initiate the heartbeat

• To fill the ventricles completely before contraction

• To close the heart valves

• To regulate blood pressure

Which heart sound is associated with systole?

• S4, the 'atrial' sound

• S3, the 'gallop' sound

• S2, the 'dub' sound

• S1, the 'lub' sound

What does the QRS complex on an EKG represent?

• Atrial depolarization

• Atrial repolarization

• Ventricular depolarization

• Ventricular repolarization

During which phase do the ventricles fill with blood?

• Isovolumetric relaxation

• Diastole

• Isovolumetric contraction

• Systole

How is cardiac output calculated?

• Heart rate divided by stroke volume

• Stroke volume divided by heart rate

• Stroke volume minus heart rate

• Heart rate times stroke volume

What is the normal range for ejection fraction?

• 40-60%

• 30-50%

• 55-75%

• 80-100%

What is the purpose of cardiac index?

• To measure heart rate

• To adjust cardiac output for body size

• To determine blood pressure

• To calculate stroke volume

What does preload refer to in cardiac terms?

• The force of heart contraction

• The stretch or filling pressure of the heart

• The volume of blood ejected per beat

• The pressure the heart pumps against

Which factor is NOT a determinant of stroke volume?

• Preload

• Afterload

• Contractility

• Heart rate

What happens to cardiac output if preload decreases?

• It decreases unless compensated by other factors

• It remains unchanged

• It doubles

• It increases automatically