Cardiac output

Definition

Cardiac output is the volume of blood the heart pumps per minute, calculated as the product of heart rate and stroke volume. This measurement is crucial in understanding how well the heart is functioning and its ability to supply oxygenated blood to the body, particularly in conditions like atherosclerosis and hypertension where circulation may be impaired.

5 Must Know Facts For Your Next Test

1. Normal cardiac output for an adult at rest ranges from 4 to 8 liters per minute, depending on individual factors such as body size and health status.
2. Increased cardiac output can occur during exercise or stress when the body demands more oxygen and nutrients, while decreased output can signal heart failure or other cardiovascular issues.
3. Atherosclerosis, characterized by the buildup of plaque in arteries, can lead to reduced blood flow and lower cardiac output due to increased resistance in the blood vessels.
4. Hypertension can lead to left ventricular hypertrophy, where the heart muscle thickens, potentially decreasing stroke volume and thus affecting overall cardiac output.
5. Monitoring cardiac output is vital in clinical settings as it helps evaluate a patient's cardiovascular health and response to treatments.

Review Questions

• How does stroke volume influence cardiac output in individuals with atherosclerosis?
  • Stroke volume directly affects cardiac output because it determines how much blood is pumped with each heartbeat. In individuals with atherosclerosis, narrowed arteries increase resistance against which the heart must pump, potentially decreasing stroke volume. As a result, if stroke volume decreases due to increased resistance, it can lead to lower cardiac output, compromising the delivery of oxygen and nutrients to tissues.
• Discuss the relationship between hypertension and cardiac output, especially regarding long-term effects on heart function.
  • Hypertension can significantly impact cardiac output over time. When blood pressure is consistently high, the heart works harder to pump blood against this elevated pressure. Initially, this might not affect cardiac output much; however, over time it can lead to structural changes such as left ventricular hypertrophy. As the heart muscle thickens and becomes less efficient, stroke volume may decrease, ultimately reducing overall cardiac output and increasing the risk of heart failure.
• Evaluate the implications of altered cardiac output for patient management in cases of chronic hypertension and atherosclerosis.
  • Altered cardiac output in patients with chronic hypertension and atherosclerosis has significant implications for their management. Reduced cardiac output indicates that the heart is not efficiently meeting the body's demands, which can lead to complications like heart failure or organ dysfunction. Clinicians must carefully monitor these patients' cardiac function and adjust treatment plans accordingly. This may involve medication to manage blood pressure, lifestyle modifications, and possibly interventions aimed at improving coronary blood flow and overall cardiovascular health.

Related terms

stroke volume: Stroke volume is the amount of blood ejected by the left ventricle of the heart with each contraction.

heart rate: Heart rate refers to the number of times the heart beats per minute, influencing cardiac output when combined with stroke volume.

hypertension: Hypertension is a condition characterized by consistently elevated blood pressure, which can strain the heart and affect cardiac output.