Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Cardiac monitoring part 4: Monitoring the apex beat

  • Comment

Phil Jevon

PGCE, BSc, RN, is resuscitation officer/clinical skills lead at Manor Hospital, Walsall

Checking the radial pulse is an unreliable method of assessing the ventricular rate in patients with atrial fibrillation. If the ventricular rate is rapid, some contractions may not be strong enough to transmit an arterial pulse-wave through the peripheral artery, resulting in an apex-radial pulse deficit (Lip, 1993).

Checking the radial pulse is an unreliable method of assessing the ventricular rate in patients with atrial fibrillation. If the ventricular rate is rapid, some contractions may not be strong enough to transmit an arterial pulse-wave through the peripheral artery, resulting in an apex-radial pulse deficit (Lip, 1993).

Simultaneous monitoring of the apex beat and radial pulse is therefore advisable in patients who have atrial fibrillation, because it will determine the ventricular rate more reliably and ascertain whether an apex beat-radial pulse deficit is present. However, routine apex beat-radial pulse monitoring is not usually undertaken if electrocardiogram (ECG) monitoring is available.

Atrial fibrillation

The incidence of atrial fibrillation in the general population is approximately 1%, rising to 10% in people aged over 70 years (Goodacre and Irons, 2002). Atrial fibrillation can complicate or cause many other medical conditions, including stroke and heart failure (Navas, 2003). The associated higher levels of mortality and morbidity have been attributed to the increased risk of arterial thromboembolism and ischaemic stroke.

Atrial fibrillation is a cardiac arrhythmia often characterised by an irregular radial pulse. The atria quiver (fibrillate) rather than contract in a controlled manner, reducing stroke volume and cardiac output. Classical features on the ECG (Fig 1) include a wavy, irregular baseline of ‘f’ (fibrillation) waves as opposed to ‘P’ waves, with an irregular and often rapid ventricular response (Goodacre and Irons, 2002).

Rate control

Controlling the ventricular rate in atrial fibrillation provides important benefits for the patient in terms of symptoms, quality of life and prevention of late consequences of uncontrolled rate such as tachycardia-induced cardiomyopathy.

Digoxin, calcium-channel blockers and beta-blockers can be used to control the ventricular rate. Digoxin is rarely prescribed for the rapid control of the heart rate, although it is commonly prescribed for chronic atrial fibrillation (Singer and Webb, 2005). The main reason for prescribing it in atrial fibrillation is to control the ventricular rate, especially when there is associated heart failure (Jowett and Thompson, 1995). Digoxin slows the ventricular rate by:

Increasing vagal tone;

Prolonging the refractory period of the atrioventricular (AV) junction;

Decreasing sympathetic activity by suppressing the baroreceptors (Resuscitation Council UK, 2006).

Monitoring the apex beat

In patients with atrial fibrillation, some contractions may not be strong enough to transmit an arterial pulse-wave through the peripheral artery if the ventricular rate is rapid, resulting in an apex-radial pulse deficit (Lip, 1993). 

It is helpful to monitor the apex beat and the apex-radial pulse deficit when a patient is prescribed digoxin in order to assess the drug’s effectiveness. The maintenance dose to be used is usually determined by the ventricular rate at rest; this should not be allowed to fall below 60bpm except in special circumstances, such as the concomitant administration
of beta-blockers.

Procedure 

A suggested procedure, to be carried out by two nurses, is as follows;

Explain the procedure to the patient and obtain consent;

Ask the patient to rest for 15 minutes before the procedure; 

Assemble equipment, including stethoscope, observation chart, watch, blue and red pens; 

Expose the patient’s chest, taking care to maintain her or his privacy and dignity at all times;

Ask the patient to breathe normally and to try to relax;

Palpate the radial pulse (first nurse) (Fig 2);

Using the diaphragm of the stethoscope, locate the apex beat, usually just outside the midclavicular line in the 5th or 6th left intercostal space (second nurse) (Epstein et al, 2005) (Fig 3);

At an agreed starting time, start counting the radial pulse and apex beat simultaneously for one minute (Fig 4); 

Document the results, apex in red and radial in blue. A wide apex-radial pulse deficit indicates inefficient cardiac contraction (Jevon et al, 2001) (Fig 5);

If the apex beat is under 60bpm withhold digoxin and inform medical staff, unless medical instructions indicate otherwise;

If the apex beat is above 60bpm administer digoxin following the prescriber’s instructions (Fig 5). 

  • Comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Links may be included in your comments but HTML is not permitted.