The Apex Beat and palpation of the chest wall
The apex beat is the lateral most point of the cardiac impulse palpable on the chest wall. It is usually localized with reference to the rib level at which it occurs- representing the x-axis, with the mid clavicular line, representing the y axis. The mid-clavicular line is drawn from a point midway along the clavicle and descending vertically downwards, and often does not coincide with the location of the nipple. The apex is usually located in the fifth intercostal space in the mid-clavicular line. Laterally displacement may be best described with reference to the anterior axillary line or even the mid axillary line. (Insert illustration here)
The apex beat is usually observed with the patient lying at 45° to the horizontal. If not identified, it can sometimes be accentuated by sitting the patient forward or rotating the patient to the left side.
The apex beat can often be seen, especially in slim persons. The normal pulse is about 3 cm in diameter. Examine the left and right sides of the chest in case of dextrocardia.
Palpation with the palm of the hand and fingers should start at a lateral position and move more anteriorly in order to avoid missing a displaced beat. A displaced apex beat usually indicates dilation of the left ventricle. Hypertrophy generally does not lead to a displaced apex beat.
A normal apex beat is about 3-4cm in diameter, or a little more than 1.5 fingertips. A wider diameter apex beat suggests dilation of the left ventricle.
(a) The hyperkinetic apex
(also referred to as hyperdynamic or pressure loaded)
This is a forceful and sustained apical impulse, often seen in left ventricular hypertrophy due to whatever cause.
(b) The sustained apical movement.
A sustained apex beat suggests cardiomyopathy or severe aortic stenosis.
c) The double apical impulse
This is a distinct double movement of the apex with sinus rhythm, that may be found in hypertrophic cardiomyopathy. , a left ventricular aneurysm involving the anterior wall or apex
The further palpation of the chest wall
The palpation of the chest wall during the cardiac exam should not end with the palpation of the apex. There is more to be found.
a) Palpating for a left parasternal heave
Normally only a slight inward movement is palpable. A sustained outward movement is referred to as a heave. The presence of a left parasternal heave suggests dilation of the right ventricle, an anterior mediastinal structure. It can also be due to marked left atrial dilatation as may be seen in mitral stenosis.
A systolic downward movement of the right ventricle may also be felt in the epigastrium. This may be palpated by placing the palmar aspect of your thumb under the left costal margin with the tip of the thumb towards the xiphoid process. An enlarged right ventricle can be felt tapping downwards on the surface of the thumb. Sometimes it is necessary to ask the patient to take and hold a deep breath to palpate the enlarged ventricle.
b) Hyperkinetic movement of the left sternal edge
Unlike a left parasternal heave, this is a non-sustained outward movement of the left sternal edge. Most commonly this is due to a hyperdynamic circulation for example due to fever, but it may be a sign of an atrial septal defect- in this circumstance it is caused by increased filling of the right ventricle. Look for the fixed splitting of the second heart sound, a prominent y decent in the neck veins, a soft systolic murmur in the 2nd left intercostal space as other signs to support this diagnosis.
c) Hyperkinetic movement of the right parasternal edge
This is found in severe tricuspid regurgitation, or mitral regurgitation. In the former it is due to expansion of the right atrium and liver, in the latter dilation of the left atrium.
d) Left parasternal movement in severe mitral regurgitation
In patients with very severe mitral regurgitation the left atrium of the heart can become massively dilated, and its rapid filling during ventricular contraction can push the heart forward creating a late systolic left parasternal impulse. This occurs even when the right ventricle, which overlies the left atrium, is of normal dimensions.
A thrill is a vibration like movement of the chest wall caused by turbulent blood flow over a heart valve. It is a palpable murmur . Thrills are usually best palpated using the distal palm. Aortic and pulmonary stenotic lesions produce murmurs that are best felt with the patient leaning forward and in full expiration.
f) A palpable P2
A palpable pulmonary component of the second heart sound (P2) is considered a sign of pulmonary hypertension. It is felt with the fingertips as a tapping movement. Palpate over the pulmonary area of the chest- the left sternal edge, second intercostal space, again with the patient sitting forward.