Cardiac Foci: Definition and Elements Involved in Cardiac Exploration Techniques

Auscultation of a heart begins with two critical items: a stethoscope and a patient.

Knowledge about these two elements is key to assessing the health of a heart.

Stethoscopes

Classic stethoscopes have two sides of the chest: the diaphragm and the bell.

The larger and flatter side is the diaphragm and is used to hear higher pitched sounds.

The bell is the smaller, concave side that allows the auscultation of lower pitched sounds, such as some heart murmurs.

When conducting a cardiac examination, auscultation should be done with the diaphragm and then repeated with the bell.

Auscultation exam techniques

The patient is usually approached from the right side and the cardiac examination always begins with the correct positioning of the patient.

The patient should be positioned and the examination bed or table should be adjusted to allow sequential examination of the seated, reclining, and left lateral decubitus patient.

Sitting positions include the upright position, the back reclined at an angle of approximately 45 degrees, and any other angle that optimizes the inspection of the neck vein.

Additional patient positions during advanced dynamic auscultation may include standing and squatting, face down in bed, and leaning forward while standing or sitting.

Both the examiner and the patient should be comfortable. The patient should wear a gown appropriately so that the examiner can reach the skin of the chest wall without having to rummage through the patient’s clothing.

Proper auscultation should not be done through clothing. The stethoscope should be applied directly to the skin.

There should be lighting to cast tangential shadows on the skin on the right side of the neck, so that the internal and external jugular veins can be inspected while simultaneously listening to the heart.

Cardiac foci

The heart has five listening zones, the auscultation locations centered around the heart valves.

The aortic, pulmonary, tricuspid, and mitral valves are four of the five auscultation points. The fifth is Erb’s point, located to the left of the sternal border in the third intercostal space.

The aortic point

The aortic point is to the right of the sternal border in the second intercostal space.

The pulmonary point

The pulmonary point is to the left of the sternal border in the second intercostal space.

The sound emitted from the aortic and pulmonary points is the S2 “doubling” of the typical “lub-dub” heart rate. The S1 and S2 sounds are present in normal heart beat patterns.

Erb’s point

It is located to the left of the sternal border, in the third intercostal space (separation between base and apex).

tricuspid point

The tricuspid point is to the right of the sternal border in the fourth intercostal space.

The mitral point

The mitral point is located in the center of the middle clavicle on the left side of the chest in the fifth intercostal space.

Both the tricuspid and mitral points are where the S1 “lub” can be heard.

The base of the heart is where the S2 aortic and pulmonary sound will be loudest.

The apex is where the tricuspid and mitral sound of S1 is loudest during auscultation.

The vertex region will also be where the S3 and S4 sounds (additional heart sounds are not usually seen in normal evaluations) and murmurs of mitral stenosis can be heard, if present.

It is important to perform a comprehensive assessment of the heart, listening to all five points and taking into account which side of the chest to use while listening, as well as the position of the patient during auscultation.

Patient positioning

Positioning the patient during the evaluation facilitates auscultation of various valve abnormalities.

Initially, a full auscultation evaluation should be performed as the patient is in a supine or sitting position.

Patients should then be positioned laterally on their left side so that the provider can listen with the bell of the stethoscope for any S3, S4 (additional heart sounds) and / or murmurs of mitral stenosis in the apex region.

Pulmonary and aortic lung murmurs are most easily identified with the diaphragm of the stethoscope when patients are sitting, leaning forward, and exhaling.