Apical Pulse: Definition, Location and How It's Taken

What is apical pulse?

Apical pulse is also known as point of maximum pulse or PMI. The apex of the heart is on the left side of the chest in a healthy individual and the heart points downwards towards the left. The person has to first locate the apical pulse, then measure it and then interpret the findings.

Cardiac function is the ability of the heart to pump blood to the other body parts. By listening to the pulsation which is the apical pulse, it can be measured. This apical pulse is located at the heart apex. By evaluating the apical pulse, we can assess the cardiac function. It is a reliable and non-invasive method.

The pulsation consists of two sounds:

• S1 - the sound of the tricuspid and mitral valves closing just before the systolic contraction can begin and when the ventricles are filled is called as S1.
• S2 - the sound of the pulmonic and aortic valves closing at the end of the systolic contraction is referred to as S2.

It is important to place the stethoscope at the heart's apex to hear the heartbeat clearly and it is also important to know the anatomical landmarks and make use of them to determine the apical pulse. The number of times the heart beats per minute is called heart rate. A stethoscope helps to amplify the sound of the apical pulse.

Locations of your pulse

There are various pulses that can be felt in different parts of the body:

• On the wrist of the hand, below the thumb is the radial pulse.
• In the neck, on both the sides of trachea is the carotid pulse.
• Within the elbow is the brachial pulse.
• Top center of the foot is the pedal pulse; this cannot be easily palpitated.
• Between the trunk and the leg fold in the groin is the femoral pulse.
• Behind the knee is popliteal pulse.
• At the ankle, on the interior of the leg is the posterior tibial pulse.

Factors that may affect the apical pulse rate and rhythm are:

• Age.
• Exercise.
• Position.
• Temperature.
• Medications.
• Sympathetic stimulation.

Device used to measure apical sound

A stethoscope is used to measure apical pulse. It amplifies the sound so that it can be transferred into the listener’s ears.

It consists of earpieces, tubing, bell, diaphragm and binaurals. The earpiece should fit in the ears. The binaurals should keep the earpiece in its place. The tubing should be flexible, not long since it may decrease the transmission of sound. For amplification, the bell needs to be held tightly against the skin.

Steps to measure apical pulse

Generally, two people are required to measure the pulse. Usually, the first person measures the apical pulse and the second one measures the radial pulse. If there is a difference in the radial and apical pulse, then it is known as a pulse deficit.

Firstly, it is vital to identify the anatomical landmarks. This helps to place the stethoscope properly at the fifth intercostal space. In order to locate the suprasternal notch, instruct the patient to lie on the left side.

• Let the patient expose the sternum and the left side of the chest. This enables better access to the chest and also to place the stethoscope.

• With a cotton swab dipped in alcohol, clean the earpiece and diaphragm of the stethoscope. This step basically reduces any risk of transmission of microorganisms from one client to another.

• Put the stethoscope around the neck.

Locating the apex of heart

• Behind and to the left of the sternum is the heart. The base is at the top and the apex is pointing downwards. Find the angle of Louis between the body of the sternum and the manubrium of the sternum, a little below the sternal notch. 

• Slip your fingers down from the angle to find the intercostal space, which is the space between two ribs. As you move your fingers down, count the number of ribs. As you count the ribs, move towards the fifth intercostal space which is between the fifth and sixth rib.

• On the left side from the middle of the clavicle through the nipple, draw an imaginary line. This line is the midclavicular line. The intersection of the midclavicular line and intercostal space is where the apical pulse can be felt. Palpate the PMI point of maximal impulse and place your nondominant hand index finger on it.

• Put the earpiece of the stethoscope in the ear with dominant hand. Psychomotor exterity is facilitated when you use dominant hand. Hold the diaphragm and place the diaphragm in your palm for five to ten seconds so that it becomes a little warm. Heat warms the diaphragm so that the patient does not get startled at the touch of the cold diaphragm.

• Place this diaphragm at the place where apical pulse could be felt. Instruct the patient to breathe normally through the nose as this reduces the breathing sound so that the heart sound can be easily heard.

• Auscultate S1 and S2 sounds so that a lub-dub sound is heard. The sound is taken as a single beat. Before you count, look for regular rhythm. This ensures accurate measurement.

• Count how many single beats can be heard in a minute. Counting can be done using a watch with a second hand.

• If the rhythm is regular, then count for 30 seconds and then multiply the count by 2. However, if the rhythm is irregular, then count for one minute.

• This helps to determine apical pulse. Record the rate, rhythm and irregular beats, if there are. Along with rate, characteristics can also be recorded. This ensures accurate documentation.

• The findings can be discussed with the patient. Assist the patient to return to a comfortable position.

Recording and interpreting apical pulse

• In newborns to three-year-old children, the apical pulse is 80-149 beats per minute.
• In four to nine-year-old children, the apical pulse is 75-120 beats per minute.
• In ten to fifteen-year-olds, the apical pulse is 50-90 beats per minute.
• In adults, the apical pulse is 60-100 beats per minute.

Well trained athletes can have a low apical pulse. It may be as low as 40. A rate of above 100 can be found in people exercising.

Interpretation

• If the apical pulse is faster than normal, it can be due to some factors such as infections, cardiac disease, hypertension or exercise.

• A slow apical pulse may be conditioning of the heart for a healthy individual. Also in some elderly individuals, medications such as beta-blockers may slow the heartbeat.

• Due to various reasons, the apical pulse may get displaced from its original location and may shift towards the right or left. Conditions such as lung disease cause the apical pulse to get shifted. In order to facilitate more flow of air into the lungs, the diaphragm is pulled downwards. This causes the displacement of the heart towards the right. In obese and pregnant women, the apical pulse shifts towards the left. This displacement occurs due to additional abdominal contents. Due to fatigue or damage of cells that maintain the cardiac rhythm, irregular pulse may occur in older individuals.

• Findings can even be interpreted and analyzed using the shape of the pulse. If the pulse is weak, it is an indication of low blood volume. If the apical pulse is sharp, it may indicate stiffness in arteries. Since the arteries are stiff, there is less space for the increased blood to flow from the heart.

• Apical pulse greater than 100 beats - It could be because of fear, anxiety, fever, exercise, low blood pressure, lack of oxygen and pain. Look for the flowing signs: dyspnea, chest pain, syncope, orthopnea, edema, dizziness, cyanosis, palpitations, and fatigue.

• Apical pulse less than 60 beats per minute - It could indicate factors such as antiarrhythmic drugs that could decrease heart rate. Look for the same signs as above. Do another apical pulse measurement and withhold the medications that may alter the heart rate till the report findings are shown to a health care provider. There may be a need to alter the dosage.

• Irregular apical rhythm - Check the pulse deficit. Show the reports to the health care provider. In order to detect cardiac conduction altercation, he may ask to perform electrocardiogram.

Pediatric Considerations

• Children under the age of two should be assessed by measuring their apical pulse.
• The child or baby should be asleep or at rest and not eating, feeding, or crying. These states tend to increase their heart rate.
• In children under the age of 2 years, the apical pulse is the most reliable method and it should be counted for 1 full minute.
• In infants, the PMI is located near the left sternal border at the third or fourth intercostal space.
• Do not tell the child to hold their breath. It will affect the apical pulse.

Gerontological Considerations

• With age, the anterior posterior diameter of the chest increases and since the left ventricle enlarges, the heart gets repositioned hence palpitating PMI becomes difficult.
• Because the air space in the lungs increases in older individuals, it becomes difficult to hear the sounds.
• In older adults, the heart rate is lower in resting position.