Apex beat
Encyclopedia
The apex beat, also called the point of maximum impulse (PMI), is the furthermost point outwards (laterally) and downwards (inferiorly) from the sternum at which the cardiac impulse can be felt. The cardiac impulse is the result of the heart
rotating, moving forward and striking against the chest wall during systole
.
It is also known as the "apical impulse".
left 5th intercostal space, at the point of intersection with the left midclavicular line. In children the apex beat occurs in the fourth rib interspace medial to the nipple. The apex beat may also be found at abnormal locations; in many cases of dextrocardia
, the apex beat may be felt on the right side.
. The apex beat may also be displaced by other conditions:
Sometimes, the apex beat may not be palpable, either due to a thick chest wall, or conditions where the stroke volume
is reduced; such as during ventricular tachycardia
or shock.
The character of the apex beat may provide vital diagnostic
clues:
An algorithm for the classification of some common apex beat characters is shown in the image.
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
rotating, moving forward and striking against the chest wall during systole
Systole (medicine)
Systole is the contraction of the heart. Used alone, it usually means the contraction of the left ventricle.In all mammals, the heart has 4 chambers. The left and right ventricles pump together. The atria and ventricles pump in sequence...
.
It is also known as the "apical impulse".
Identification
The normal apex beat can be palpated in the precordiumPrecordium
In anatomy, the precordium is the portion of the body over the heart and lower chest.Precordial chest pain can be an indication of a variety of illnesses, including costochondritis and viral pericarditis....
left 5th intercostal space, at the point of intersection with the left midclavicular line. In children the apex beat occurs in the fourth rib interspace medial to the nipple. The apex beat may also be found at abnormal locations; in many cases of dextrocardia
Dextrocardia
Dextrocardia is a congenital defect in which the heart is situated on the right side of the body. There are two main types of dextrocardia: dextrocardia of embryonic arrest and dextrocardia situs inversus...
, the apex beat may be felt on the right side.
Interpretation
Lateral and/or inferior displacement of the apex beat usually indicates enlargement of the heart, called cardiomegalyCardiomegaly
Cardiomegaly is a medical condition wherein the heart is enlarged. It is generally categorized in the following manner:* Cardiomegaly due to dilation* Cardiomegaly due to ventricular hypertrophy** Left ventricular hypertrophy...
. The apex beat may also be displaced by other conditions:
- Pleural or pulmonary diseases
- Deformities of the chest wall or the thoracic vertebra
Sometimes, the apex beat may not be palpable, either due to a thick chest wall, or conditions where the stroke volume
Stroke volume
In cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. SV is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat from the volume...
is reduced; such as during ventricular tachycardia
Ventricular tachycardia
Ventricular tachycardia is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart...
or shock.
The character of the apex beat may provide vital diagnostic
Diagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
clues:
- A forceful impulse indicates pressure overload in the heart (as might occur in hypertensionHypertensionHypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
) - An uncoordinated (dyskineticDyskinesiaDyskinesia is a movement disorder which consists of effects including diminished voluntary movements and the presence of involuntary movements, similar to tics or choreia. Dyskinesia can be anything from a slight tremor of the hands to uncontrollable movement of, most commonly, the upper body but...
) apex beat involving a larger area than normal indicates ventricular dysfunction; such as an aneurysm following myocardial infarction
An algorithm for the classification of some common apex beat characters is shown in the image.