New: Examination of the Cardiac Apex Beat
Understanding the apex beat is crucial for medical students and practitioners. It’s not just a physical sign, but a gateway to in-depth cardiac diagnosis. This article provides a comprehensive overview, designed to enhance your clinical skills in cardiology.
Apex beat is the palpable cardiac apex impulse. It is the lowermost and outermost (most lateral and most inferior) prominent cardiac pulsation in the precordium. Examination of this cardiac impulse can give valuable inputs into the diagnosis of cardiac diseases, by identifying many abnormalities including tapping, hyperdynamic and heaving apical impulses.
Where is the location?
It usually is present in the left fifth intercostal space, about one centimetre medial to the mid-clavicular line (MCL).
Apex beat is located in the 4th intercostal space, just lateral to the MCL in children less than seven years of age.
It is inaccurate to use any other reference for the apex beat other than the MCL (e.g., 10 cm lateral from the midline, 8 cm lateral to left sternal edge, etc.). However, the examiner should identify the MCL carefully (midpoint between the sternoclavicular and acromioclavicular joints).
Recommended Reading: Check out this introduction to Respiratory Auscultation with audio examples.
What is the mechanism of apex beat production?
One of my students asked this very pertinent question:
“When the heart contracts, it expels blood towards the great arteries, that is towards the base of the heart. Then why does the apex beat move ‘outward’ in the chest?”
The heart has a spiral arrangement muscle in a syncytium. When this muscle contracts, the heart rotates, and the apex moves forward toward the chest wall and taps it.
How do we examine? Method of examination:
Position the flat of your hand so that the middle finger lies on the left 5th intercostal space of the patient, covering the anterolateral ribcage. Position your other fingers on the intercostal spaces above and below. If you feel no pulsation, move the hand in different directions, feeling for a pulsation.
After feeling the apex beat, ascertain whether it is the most prominent pulsation. Then, to identify the position, palpate the sternal angle (angle of Louis). It is the angle between the manubrium and the body of the sternum. The second rib corresponds to this angle. Below the second rib is the corresponding intercostal space. Starting from that space, count the intercostal spaces and reach the palpable apex and identify the intercostal space in which it is present.
Subsequently, measure the distance between the apex impulse and the mid-clavicular line. If the pulsation is nearer to any other vertical landmark line, like the anterior or middle axillary lines, it is better to state the position in relation to those lines rather than mid-clavicular line. For example, instead of mentioning that the apex is 6 cm lateral to the mid-clavicular line, it is better to document as one cm medial to mid-axillary line.
Examination Method Simplified
- Initial Position: Place the flat of your hand on the patient’s left 5th intercostal space, covering the anterolateral ribcage.
- Search for the Beat: If no pulsation is felt, gently move your hand in various directions to locate it.
- Determine Prominence: Confirm if the apex beat is the most prominent pulsation.
- Identify Location: Palpate the sternal angle and count down the intercostal spaces to pinpoint the exact location of the apex beat.
- Measure Distance: Note the distance between the apex impulse and the nearest landmark line, such as the mid-clavicular or axillary lines.
What do we note in the apex?
- Size (is it localised or diffuse?)
- Amplitude (is it forceful?)
- Duration (is it abnormally sustained?)
- Type (assess based on above parameters, details are below)
What causes ABSENCE of the apex beat?
Absent apical impulse may be due to physiological and pathological causes. This mnemonic is helpful: DR POPE
- Dextrocardia. Though it will be missing at the ‘usual’ location on the left side, it will be present on the right side.
- Apex is behind a Rib. In this case, it may not be palpable in an intercostal space. Just turning the patient to the left lateral position will reveal the apex beat, confirming this cause.
- Pericardial effusion
- Obesity and thick chest wall
- Pleural effusion (left sided)
What causes DISPLACEMENT of the apex beat?
Assessment of the tracheal position is important, because, tracheal deviation, along with the displacement of apex impulse, suggests mediastinal shift as a result of lung fibrosis, collapse, pneumothorax etc.
If the trachea is central, but the apex is displaced, the causes are:
- Left ventricular enlargement – the apex displacement is downwards and lateral.
- Right ventricular enlargement – the apex displacement is lateral.
- Cardiomegaly due to significant enlargement of other chambers can also cause displacement
- Pectus excavatum
- Situs inversus/ dextrocardia
A laterally displaced apex impulse in a supine patient indicates the following:
- Reduced ejection fraction
- Increased left ventricular end-diastolic volume
- Increased pulmonary capillary wedge pressure
- Enlarged heart on chest X-ray
Which are the abnormal types (characters) of apex beat?
The normal apex beat is a localised pulsation in the normal location as described above. Here are some abnormal characters (please refer to the algorithm shown in the picture below, too):
- Tapping Apex – This is an almost normal apex impulse with a palpable first heart sound. Importantly, we have to recognize that the feeling of tapping is due to the loud first heart sound heard in mitral stenosis.
- Hyperdynamic Apex – This is classically seen in volume overload conditions where there is ventricular dilatation (aortic regurgitation, hyperdynamic circulation etc.). Hyperdynamic apex is a forceful but ill-sustained pulsation that is palpable over a larger area than usual (diffuse).
- Heaving Apex – Classically seen in pressure overload conditions that result in ventricular hypertrophy (aortic stenosis, systemic hypertension etc.). Heaving apex is a forceful and sustained pulsation that is typically localised.
- Double Impulse Apex – Two impulses felt during systole rather than the normal single pulsation. We see this in HCM (hypertrophic cardiomyopathy), as the poor left ventricular compliance results in an S4 (fourth heart sound). A palpable S4 and the sustained apex impulse give an impression of ‘double’ impulse in this condition.
- Dyskinetic Apex – An apex that is uncoordinated, seen in myocardial infarction when there are dyskinetic movements of the infarcted myocardium (typically an apical ventricular aneurysm).
- Retracting Apex – In patients with constrictive pericarditis, the apex ‘retracts’ during systole. Consequently, the fibrosed pericardium prevents the normal outward thrust during systole but allows rapid filling of the left ventricle during diastole. This contributes to the impression that the apex is ‘retracting’ during systole.
Is there anything else? Some apex related terminology clarified:
- Localized apex beat: Palpable in a single intercostal space and the longest diameter of the pulsation is within 4 cm. A localized apex is normal.
- Diffuse apex beat: Apex palpable in more than one intercostal space or longest diameter more than 4 cm, even within a single intercostal space.
Mastering the assessment of the apex beat is a fundamental skill in cardiology. It’s a window into the heart’s health and a critical component of a thorough physical examination.