Examination of the Cardiovascular System

Again, some information regarding the examination of CVS which I took from Kumar and Clark's relating mainly to the examination mentioned in Part A of this PCL.

Arterial Pulse

· Pulse rate

o Pulse rate – between 60-80 bpm when adult patient is lying quietly in bed

o Young children maybe have higher pulse rates where else athletes and elderly adults may have slower rates.

o When pulse is irregular not all ventricular systolic beats maybe be detected by palpation of the radial pulse.

o Apex-radial pulse deficits maybe appreciated by counting the radial pulse simultaneously while listening to the heartbeat with a stethoscope. Commonly associated with atrial fibrillation and ventricular ectopy.

Blood Pressure

Jugular venous pressure

o There are no valves between the internal jugular vein and the right atrium.

o Observation of the column of blood in the internal jugular system is therefore a good measure of right atrial pressure.

o The external jugular cannot be relied upon because of its valves and because it may be obstructed by the fascial and muscular layers through which it passes; it can only be used if typical venous pulsation is seen, indicating no obstruction to flow.

o Measurement:

§ Hepatojugular reflex – When abdomen compressed causing temporary increase in central and hence jugular venous pressure. Confirms venous nature of a pulsation in the neck

§ Cannot be measure if low jugular venous pressure due to haemorrhage or other forms or hypovolemia

Intepretation Of The Jugular Venous Pressure Wave

This consists of three peaks and two troughs .The peaks are described as a, c and v waves and the troughs are known as x and y descents:

· The a wave is produced by atrial systole. Distinguished from the v wave by observing venous pulse while palpating the carotid artery. a wave occurs immediately after carotid pulsation while v wave occurs simultaneously.

· The x descent occurs when the atrial contraction finishes.

· As the pressure falls there is a small transient increase that produces a positive deflection called the c wave. This is caused by transmission of the rapidly increasing right ventricular pressure before the tricuspid valve closes.

· The v wave develops as the venous return fills the right atrium during continued ventricular systole.

· The y descent follows the v wave when the tricuspid valve opens.

Main abnormalities:

· Large a waves –

o Causes

§ resistance to ventricular filling, as seen with right ventricular hypertrophy due to pulmonary hypertension or pulmonary stenosis

§ tricuspid stenosis, but unusual because patients with tricuspid stenosis are usually in atrial fibrillation and therefore do not have a waves.

o A very large a wave occurs when the atrium contracts against a closed tricuspid valve; this is known as a 'cannon wave'. Cannon waves occur irregularly in complete heart block and in ventricular tachycardia.

· Large v waves –

o Caused by tricuspid regurgitation because the right ventricular pressure is transmitted directly to the right atrium and the great veins.

· Steep y descent –

o Diastolic collapse of elevated venous pressure can occur in right ventricular failure but is more dramatic in constrictive pericarditis and tricuspid regurgitation.

o At the end of ventricular systole the elevated atrial pressure suddenly falls when the tricuspid valve opens.

o However, the ventricles are stiff and cannot be distended and therefore, the venous pressure rapidly rises again. This rapid fall and rise of the jugular venous pulse is known as Friedreich's sign.