Assessment and Observation of the Cardiovascular System

Learning objectives for this chapter

By the end of this chapter, we would like you:

-To describe the basic anatomy and physiology of the cardiovascular system.

-To explain how to collect a focused health history related to the cardiovascular system.

-To discuss the importance of a patient’s reports of chest pain in the cardiovascular assessment, and to identify factors which can assist with a differential diagnosis of the cause of chest pain.

-To identify cardiovascular risk factors which may become apparent when collecting a cardiovascular health history.

-To explain how to undertake a physical examination of the cardiovascular system.

-To identify and explain the cause of a variety of different abnormal heart sounds.

-To describe the variety of special assessment techniques which may be used in the physical examination of the cardiovascular system, including electrocardiogram (ECG).

Fundamental anatomy and physiology of the cardiovascular system

The cardiovascular system is comprised of the heart and the system of vessels which transport blood to, and metabolic wastes from, all parts of the body. It is a dynamic system, with the capacity to adjust to changing conditions and demands.

The heart is a pump comprised of four chambers – two atria and two ventricles. The right side of the heart receives deoxygenated blood from the body via the superior and inferior vena cavae, and pumps it into the pulmonary circulation for reoxygenation. Deoxygenated blood leaves the heart via a large vessel known as the pulmonary artery. The left side of the heart receives oxygenated blood from the pulmonary veins, and pumps it into the systemic circulation for use. Oxygenated blood leaves the heart via a large vessel known as the aorta.

There are four valves which control the flow of blood through the chambers of the heart:

• The two atrioventricular valves, including the tricuspid valve and the mitral valve.

• The two semilunar valves, including the pulmonary valve and the aortic valve.

The term ‘cardiac cycle’ is used to describe the processes involved. There are two key phases of the cardiac cycle:

• Diastole – the ventricles relax and fill with blood from the atria.

• Systole -the ventricles contract, forcing blood through the semilunar valves and into the pulmonary artery and the aorta.

The cardiac cycle is controlled by the heart’s electrical conduction system. At the beginning of each cardiac cycle, an electrical impulse travels across the heart to the atrioventricular node. The movement of this electrical impulse through the heart results in the contraction of the atria and then the ventricles.

When oxygenated blood leaves the heart, it enters the peripheral vascular system. The arteries are the vessels which carry oxygenated blood to the body. The veins are the vessels which carry deoxygenated blood back to the heart. Small vessels called capillaries permeate, and allow blood to perfuse every part of the body.

It is important to note that the lymphatic system works in tandem with the cardiovascular system; therefore, in assessing the cardiovascular system the nurse is also indirectly assessing the lymphatic system.

Cardiovascular system – focused health history

When assessing a patient’s cardiovascular system, the nurse must commence by collecting a health history. This involves collecting data about:

• Present health status
  • Chronic illnesses
  • Current medications
  • Exercise
  • Stress, and coping mechanisms
  • Dietary habits
  • Alcohol consumption
  • Caffeine consumption
  • Tobacco smoking (past and present)
• Past medical history
  • Congenital heart disease/s or heart defect/s
  • Other significant childhood illnesses
  • Surgeries on the heart or the blood vessels
  • Previous cardiac tests
• Family history of heart conditions

In some cases, a person will present with a specific problem related to their heart. If this is the case, a nurse must gather a more focused health history.

Chest pain is a particularly significant symptom indicating dysfunction in the cardiovascular system. If a patient complains of pain, they should be rapidly assessed. The location, quality, quantity, chronology, associated manifestations and aggravating / alleviating factors of the chest pain a patient experiences can provide important information about the cause of this pain – and allow the patient’s health care team to make a differential diagnosis. Review the information in the following table:

Cause of Pain	Factors Enabling Differential Diagnosis
Stable angina, or chest pain resulting from myocardial hypoxia, which occurs predictably due to a partial blockage of a cardiac vessel	Pain located the precordial / retrosternal regions, radiating from the left to the right arm, interscapular and / or epigastric regions; pain may be described as ‘pressure’, ‘burning’, ‘sharp’ or ‘dull’; pain quantity is variable but usually worse with activity; pain lasts between 1 minute and 1 hour; pain is associated with dyspnoea, diaphoresis, palpitations, nausea, weakness; pain is aggravated by exertion, stress, cold; pain is alleviated by rest, glyceryl trinitrate (GTN), beta (β) blockers, calcium channel blockers, etc.
Unstable angina or chest pain resulting from myocardial hypoxia, which occurs unpredictably due to a partial blockage of a cardiac vessel	Pain located the precordial / retrosternal regions, radiating from the left to the right arm, jaw, interscapular and / or epigastric regions; pain may be described as ‘pressure’, ‘squeezing’, ‘crushing, ‘burning’, ‘dull’ or sharp’; pain is often 10/10 on the pain scale; pain has a sudden onset, and progresses over a period of 30 to 40 minutes; pain is associated with dyspnoea, diaphoresis, palpitations, nausea, weakness; pain is aggravated by exertion; pain is alleviated by β-blockers, aspirin, heparin, oxygen, etc.
Myocardial infarction, or chest pain resulting from myocardial hypoxia, which occurs due a complete blockage of a cardiac vessel	Pain located the precordial / retrosternal regions, radiating from the left to the right arm, jaw, interscapular and / or epigastric regions; pain may be described as ‘pressure’, ‘squeezing’, ‘crushing, ‘burning’, ‘dull’ or ‘sharp’; pain is often 10/10 on the pain scale; pain has a sudden onset, and progresses over a period of >1 hour to 2 to 3 days; pain is associated with dyspnoea, diaphoresis, palpitations, nausea, weakness; pain is aggravated by exertion; pain is alleviated by β-blockers, aspirin, heparin, oxygen, etc.
Mitral valve prolapse, where the two halves of the mitral valve bulge upwards during ventricular contraction	Pain is located anywhere in the chest, it may be localised or diffuse but does not radiate; pain is variable, but often described as ‘sharp’; pain has a sudden onset, and it may last seconds or persist for days; often there are no associated symptoms, however pain may be associated with palpitations, dyspnoea and dizziness; pain may be aggravated by a person’s position; pain may be relieved by GTN, analgesics and positional change, etc.
Acute pericarditis, or inflammation of the pericardium, often due to infection	Pain may be located in the precordial, posterior neck or trapezius region; pain may be pleuritic or positional; pain is often 4/10 to 6/10 on the pain scale; pain has an onset of hours to days; pain is often associated with fever, dyspnoea and orthopnoea; pain may be relieved by positional change and treatment of the pericarditis.

As highlighted in the above table, unstable angina and myocardial infarction have very similar signs and symptoms. The key assessment a nurse may perform to differentiate between these conditions is an electrocardiogram (ECG).

It is important for nurses to realise that there are a number of conditions not related to the cardiovascular system which may result in chest pain, such as panic disorder, peptic ulcer disease, gastro-oesophageal reflux disease (GORD) and costochondritis.

As you collect a general health history from a patient, it is important that you assess and identify risk factors for: (1) hypertension, and (2) coronary artery disease. The common risk factors of each are listed in the table below:

Risk Factors for Hypertension	Risk Factors for Coronary Artery Disease
Age. Family history. African or Caribbean descent. Diet with high amounts of salt. Lack of exercise. Overweight, obesity. Consumption of large amounts of alcohol. Smoking. Long-term sleep deprivation. Some medical conditions. Some medications.	Age. Family history. Gender. Hypertension. Raised or altered levels of blood cholesterol, and / or triglycerides with low HDL-cholesterol. Diabetes. Smoking. Lack of exercise. Overweight, obesity. Consumption of large amounts of alcohol. Smoking. Excessive or chronic stress.

Cardiovascular system – physical examination

Once a cardiovascular health history has been obtained, a nurse may commence a physical examination of the patient’s cardiovascular system. This involves the following steps:

• Assess general appearance by inspecting the patient.
• Assess the peripheral vascular system.
  • Palpating the pulses.
  • Measuring the blood pressure (BP).
  • Inspecting and palpating the upper and lower extremities for turgor.
  • Inspecting and palpating the upper and lower extremities for skin integrity, colour, temperature and capillary refill.
• Assess the heart.
  • Inspecting the anterior chest wall.
  • Palpating the location of the apical pulse.
  • Measuring the heart rate (HR).
  • Measuring the oxygen saturation (SpO2).
  • Assessing the heart sounds.

Assessing the heart sounds is a key skill for nurses. There are two normal heart sounds: S₁, at systole, has a low pitch, and S₂, at diastole, has a higher pitch. However, there are a number of abnormal sounds a nurse may identify during their assessment:

• A heart sound additional to S₁ and S₂, during diastole.
• A heart sound additional to S₁, S₂ and S₃, during diastole.
• A high-pitched ‘snapping’ sound.
• A ‘clicking’ sound during systole.
• A rubbing sound.
• A low- to medium-pitched, coarse sound with a crescendo-decrescendo pattern.
• A low- to high-pitched, ‘blowing’ sound.
• A low-pitched ‘rumbling’ sound.
• A high-pitched, harsh ‘blowing’ sound.

Abnormal heart sounds are often referred to as ‘murmurs’. They are generally classified into one of two types:

• Diastolic murmurs. Most diastolic murmurs are caused by obstructions to the movement of blood into the ventricles, often due to problems with the semilunar and / or atrioventricular valves.

• Systolic murmurs. Most systolic murmurs are caused by obstructions to the movement of blood out of the ventricles, often due to problems with the semilunar and / or atrioventricular valves.

Special assessment techniques for the cardiovascular system

There are a number of special assessment techniques particular to the cardiovascular system:

• Electrocardiogram (ECG). An ECG is a measurement of the electrical activity in the heart during a cardiac cycle. An ECG recording is made using an ECG machine, with a number of probes attached to the skin around the patient’s heart and to their peripheries.

An ECG machine depicts a cardiac cycle as illustrated in the image following:

In this measurement: The P wave represents the contraction of the atria. The QRS complex represents the contraction of the ventricles. The T wave represents the relaxation of the ventricles.

An ECG is the key assessment a nurse may perform to differentiate between unstable angina and myocardial infarction. Essentially, myocardial infarct is often apparent on an ECG with changes to the section between the S- and T-sections. Angina is not apparent on ECG.

It is generally the responsibility of suitably-trained medical practitioners to interpret ECG measurements. However, it is important for nurses to be able to identify obvious problems evident on an ECG recording.

• Capillary refill time (CRT). Measuring CRT allows a nurse to assess the function of a patient’s vascular system at the level of the capillaries. A nurse measures CRT by gently squeezing the pads of a patient’s fingers until they blanche. The pressure is then released and the time for the capillaries to refill is recorded. CRT should be should be ≤2 seconds.

• Pitting oedema. When assessing for pitting oedema, the nurse gently presses the pads of their first and middle fingers into the tissue covering the bottom half of the patient’s shin. If an indentation remains after the nurse’s fingers are lifted, pitting oedema is present.

• Clubbing of the fingers. This occurs when the angle of the base of the nail bed, where it joins to the tissues of the fingers, is >160.

Additional assessments to assist with differential diagnosis of cardiovascular problems include chest X-rays or CT scans, blood tests to assess for cardiac biomarkers, and perhaps ultrasound. Although nurses generally do not perform these assessments, they have an important role in preparing the patient and in interpreting and communicating relevant findings.

Conclusion

This chapter has introduced the fundamental knowledge and skills nurses require to do so. It began with an overview of the fundamental anatomy and physiology of the cardiovascular system. The chapter then explained the processes involved in collecting a general health history for the cardiovascular system, and in performing a physical examination of the cardiovascular system. Finally, this chapter considered a number of special observation and assessment techniques which may be used in the physical examination of the cardiovascular system.