Examination of the cardiovascular system Medical Assignment Help

GENERAL EXAMINATION

General features of the patient’s well-being should be noted as well as the presence of anaemia, obesity, jaundice and cachexia .

Clubbing 

The most common cardiac causes of severe clubbing are subacute infective endocarditis and congenital cyanotic heart disease, particularly Fallot’s tetralogy. Clubbing takes many months to develop and is therefore not seen in acute endocarditis or in neonates or infants with cyanotic heart disease. Clubbing seen in cor pulmonale is due to the underlying pulmonary disease (e.g. bronchiectasis or fibrosing alveolitis).

Splinter haemorrhages

These small, subungual linear haemorrhages are most frequently due to trauma but are also caused by infective endocarditis when they may be florid.

Cyanosis

This is a dusky blue discoloration of the skin (particularly at the extremities) or of the mucous membranes. It is due to the presence of unoxygenated haemoglobin (traditionally at least 5 g dl-I of blood) and occasionally of other reduction products of haemoglobin such as sulphaemoglobin or methaemoglobin. Cyanosis is more readily provoked in the presence of polycythaemia and is uncommon when anaemia is present.

Central cyanosis

This is present when the tongue is cyanosed. It is caused by cardiac failure or respiratory disorders. The central cyanosis of pulmonary or cardiac failure is improved by breathing oxygen if the degree of shunting is small.

Peripheral cyanosis

This is due to vasoconstriction and stasis of blood in the extremities, and increased oxygen extraction by peripheral tissues. Peripheral cyanosis occurs in congestive heart failure, ‘shock, exposure to cold temperatures and with abnormalities of the peripheral circulation.

THE ARTERIAL PULSE

A pulse is felt by compressing an artery against a bone. The first pulse to be examined is the right radial pulse. The timings of the left radial and femoral pulses are then compared with that of the right radial pulse. Delayed pulsation occurs because of a proximal stenosis, particularly of the aorta (coarctation).

Rate

The pulse rate should be between 60 and 80 beats per minute (b.p.m.) when an adult patient is lying quietly in bed. Young children may have higher pulse rates and athletes and elderly adults may have slower rates. The exact rate is unimportant but changes (seen on a pulse chart) are helpful. When the pulse is irregular, not all beats may be transmitted to the wrist and it is therefore best to count the pulse whilst at the same time listening to the heart beat with a stethoscope. An apex-radial (pulse) deficit is common in atrial fibrillation.

Rhythm

In normal subjects the pulse is regular except for a slight quickening in early inspiration and a slowing in expiration (sinus arrhythmia). Irregularities of the pulse rhythm are usually due to premature beats, intermittent heart block or atrial fibrillation.
Premature beats occur as occasional or repeated irregularities superimposed on a regular pulse rhythm. Similarly, intermittent heart block is revealed by occasional beats dropped from an otherwise regular rhythm. A more irregular pattern (irregularly irregular) of heart beats occurs in atrial fibrillation. This irregular pattern persists when the pulse quickens in response to exercise in contrast to pulse irregularity due to ectopic beats, which usually disappears on exercise. However, this is not a reliable way to distinguish ectopic beats from other causes of pulse irregularity.

Carotid pulse

The amplitude and shape of the carotid pulse is examined. Usually carotid pulsation is not visible, but a very large-volume pulse may be apparent as pulsation of the neck (Corrigan’s sign). A large-volume pulse occurs in high output states and in aortic regurgitation. The carotid pulse is also visible when the carotid artery is aneurysmal or kinked. The right carotid is palpated lightly in order to detect a thrill.
A large-volume pulse with a brisk rise and fall is known as a collapsing or waterhammer pulse. It is found in the elderly when the aorta is rigid, or when the cardiac output is high, e.g. in thyrotoxicosis, anaemia orfever. Aortic valvular regurgitation or a persistent ductus arteriosus also cause a collapsing pulse. A large-volume pulse that is not collapsing in nature is associated with the large stroke volume that is necessary if bradycardia is present.

A small-volume pulse is seen in cardiac failure, shock and obstructive vascular or valvular disease. It is also present when tachycardia occurs. The pulse of aortic stenosisis not only small in volume but is slow in rising to a peak (plateau pulse) and is often associated with a notch on the upstroke (an acrotic pulse) or a systolic shudder or thrill. Other changes in arterial pulse Paradoxical pulse (pulsus paradoxus) Paradoxical pulse is a misnomer as it is actually an exaggeration of the normal pattern. In normal subjects, the systolic pressure and the pulse pressure (the differencebetween the systolic and diastolic blood pressures) fall during inspiration. The normal fall of systolic pressure is less than 10 mmHg and this can be measured using a sphygmomanometer. The reason for this fall in pressure is that the right heart responds directly to changes in intrathoracic pressure while the filling of the left depends on the pulmonary intravascular volume. Thus as the return of blood to the left ventricle falls there is a drop jn systolic pressure. At high respiratory rates this is exaggerated with the volumes of the right and left ventricles being unequal. In severe airflow limitation (especially severe asthma) there is an increased and sudden negative intrathoracic pressure on inspiration and this will enhance the normal fall in blood pressure. In patients with cardiac tamponade the fluid in the pericardium increases the intrapericardial pressure thereby reducing the heart’s filling capacity. The inspiratory increase in the right ventricle occurs very much at the expense of the left ventricle as both ventricles are confined within a relatively ‘fixed’ pericardium. Through a similar mechanism, paradox can occur in constrictive pericarditis but is less common.

Various arterial waveforms.

Various arterial waveforms.

Alternating pulse (pulsus alternans)

This is characterized by alternate beats that are weak and strong but with a regular rhythm. It is a feature of severe myocardial failure and is due to the prolonged recovery time of damaged myocardium; it indicates a very poor prognosis. It is easily noticed when taking the blood pressure because the systolic blood pressure may vary from beat to beat by as much as 50 mmHg. Pulsus alternans may also occur when there is rapid, abnormal tachycardia.
In this case it acts as a compensatory mechanism and does not indicate a poor prognosis. Pulsus alternans should be distinguished from a bigeminal pulse.
Bigeminal pulse (pulsus bigeminus) This is due to premature ectopic beats following every sinus beat. The rhythm is not regular  because every weak pulse is premature.

Pulsus bisferiens

This is a pulse that is found in hypertrophic obstructive cardiomyopathy and in aortic regurgitation combined with aortic stenosis. The first systolic wave is the ‘percussion’ wave produced by the transmission of the left ventricular pressure in early systole. The second peak is the ‘tidal’ wave caused by recoil of the vascular bed. This normally happens in diastole (the dicrotic wave), but when the left ventricle empties slowly or is obstructed from emptying completely, the tidal wave occurs in late systole. The result is a palpable double pulse. BLOOD PRESSU RE (Practical box ILl) The peak systemic arterial blood pressure is produced by transmission of left ventricular systolic pressure. The diastolic blood pressure is maintained by vascular tone and an intact aortic valve.

The normal blood pressure

There is no single blood pressure or limited range of blood pressures that is normal in all subjects and circumstances. However:
IN ARE STINGAD ULT the systolic blood pressure does not usually exceed 150 mmHg and the diastolic pressure does not exceed 90 mmHg.
IN CH[LDREN OR YOUNG ADULTS the pressures are correspondingly less.
IN THE ELDERLY the rigidity of the arterial vessels produces an increase, predominantly in the systolic blood
pressure.
THERE [S A D[URNAL VAR[ATION OF BLOOD PRESSURE, the pressure during the day being greater than at night.
ANX[ETY (for example when consulting a physician- ‘white coat’ hypertension, and exertion increase the blood pressure. Note that a cuff that is too small leads to overestimation of the pressure. For example, if a standard arm cuff size (12 ern) is used in an obese patient, the pressure measured will be too high. Similarly, if an arm cuff is used on the thigh (with the diaphragm of the stethoscope applied over the popliteal artery), the femoral pressure will be overestimated. The usual thigh cuff is 15 cm wide. Smaller cuff sizes are available for children and thin adults.

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