Cardiac Cycle and Blood Pressure

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Questions and Answers

What is the term for the difference between systolic and diastolic pressures?

Peripheral pressure

Pulse pressure (correct)

Blood pressure

Arterial pressure

What is the primary factor that affects the pulse pressure?

Left ventricular stroke volume (correct)

Volume of blood in the arterial system

Peripheral vascular resistance

Environmental temperature

Which of the following is NOT a factor that affects blood pressure?

Emotional state

Use of coffee

Distensibility of the aorta

Heart rate (correct)

What is the term for the device used to measure blood pressure?

Sphygmomanometer Signup and view all the answers

Why are pulses in the arms and legs unsuitable for timing events in the cardiac cycle?

There is a palpable delay between ventricular contraction and peripheral pulses Signup and view all the answers

What is the name of the graph that shows the blood pressure variation during the cardiac cycle?

Figure 16-16 Signup and view all the answers

What is the primary function of the jugular veins in relation to the heart?

To provide an index of right heart pressures and cardiac function Signup and view all the answers

Which of the following best reflects the pressure in the right atrium?

All of the above Signup and view all the answers

What is the name of the elevation in the jugular veins caused by retrograde blood flow into the neck veins?

A wave Signup and view all the answers

What is the characteristic of the jugular veins in a patient with tricuspid stenosis?

Abnormally prominent cannon a waves Signup and view all the answers

What is the name of the elevation in the jugular veins caused by the inflow of blood from the vena cava during right ventricular systole?

V wave Signup and view all the answers

What is the characteristic of the jugular veins in a patient with atrial fibrillation?

Absent a waves Signup and view all the answers

What is the best way to estimate jugular venous pressure?

From the right internal jugular vein Signup and view all the answers

What is the characteristic of the jugular veins in a patient with tricuspid regurgitation?

Increased v waves Signup and view all the answers

In which age group is the apical impulse usually easily palpated?

Children and young adults Signup and view all the answers

What is the significance of the cervical systolic murmur or bruit in children?

It is a normal variant with no clinical significance Signup and view all the answers

What is the characteristic of most murmurs that occur in individuals?

They occur without other evidence of cardiovascular abnormality Signup and view all the answers

What is the origin of the jugular venous hum?

It originates from the large blood vessels Signup and view all the answers

What is the significance of knowing the patterns of murmurs that vary with age?

It helps to distinguish normal from abnormal murmurs Signup and view all the answers

Study Notes

Cardiac Cycle and Blood Pressure

With each contraction, the left ventricle (LV) ejects a volume of blood into the aorta, which then perfuses the arterial tree.
The ensuing pressure wave generates the arterial pulse, but a palpable delay between ventricular contraction and peripheral pulses makes them unsuitable for timing events in the cardiac cycle.
Blood pressure in the arterial system varies during the cardiac cycle, peaking in systole and falling to its lowest trough in diastole.
The levels measured with the blood pressure cuff, or sphygmomanometer, are the peak (systolic) and lowest (diastolic) pressures.
The difference between systolic and diastolic pressures is known as the pulse pressure.

Factors Affecting Blood Pressure

Left ventricular stroke volume affects blood pressure.
Distensibility of the aorta and the large arteries influences blood pressure.
Peripheral vascular resistance, particularly at the arteriolar level, impacts blood pressure.
Volume of blood in the arterial system also affects blood pressure.
Changes in any of these four factors alter systolic pressure, diastolic pressure, or both.

Blood Pressure Fluctuations

Blood pressure levels fluctuate significantly throughout a 24-hour period.
Factors contributing to blood pressure fluctuations include:
- Physical activity
- Emotional state
- Pain
- Noise
- Environmental temperature
- Use of coffee, tobacco, and other drugs
- Time of day

Jugular Venous Pressure (JVP) and Cardiac Function

JVP reflects right atrial pressure, which equals central venous pressure and right ventricular end-diastolic pressure.
JVP is best estimated from the right internal jugular vein, which has the most direct channel into the right atrium.

Jugular Venous Pulsations

Changing pressures in the right atrium during diastole and systole produce oscillations of filling and emptying in the jugular veins.
Atrial contraction produces an a wave in the jugular veins just before S1 and systole.
The x descent occurs during continued atrial relaxation.
The v wave occurs as right atrial pressure begins to rise with inflow from the vena cava during right ventricular systole.
The y descent occurs as blood passively empties from the right atrium into the RV during early and middiastole.

Simplified Way to Remember the Three Peaks

a wave: atrial contraction
c wave: carotid transmission (or closure of the tricuspid valve)
v wave: venous filling

Abnormal JVP Patterns

Abnormally prominent cannon a waves: increased resistance to right atrial contraction, tricuspid stenosis, severe AV block, supraventricular tachycardia, junctional tachycardia, pulmonary hypertension, and pulmonic stenosis.
Absent a waves: atrial fibrillation.
Increased v waves: tricuspid regurgitation, atrial septal defects, and constrictive pericarditis.

Effects of Aging on Cardiovascular System

Aging affects the location of the apical impulse, making it harder to find in older adults due to the deepening of the chest in its anteroposterior (AP) diameter.
The pitch of heart sounds and murmurs changes with age.
Arterial stiffness increases with age.
Blood pressure is affected by aging.

Heart Murmurs and Age

Almost everyone has a heart murmur at some point in their life.
Most murmurs are normal variants and occur without other evidence of cardiovascular abnormality.
Murmurs vary with age, and understanding their patterns helps distinguish normal from abnormal.
Murmurs can originate in large blood vessels as well as in the heart.

The jugular venous hum is common in children and may still be heard through young adulthood.
The cervical systolic murmur, or bruit, may be innocent in children but suspicious for atherosclerotic disease in adults.

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Description

Learn about the cardiac cycle, including the ejection of blood into the aorta, arterial pulse, and variations in blood pressure during systole and diastole.