Heart Anatomy and Physiology Mnemonics
Anatomy of the Heart
Each half of the heart has an upper collecting chamber (the atrium), and a lower pumping chamber (the ventricle).
You can remember their location, because A comes before V – the atrium is above the ventricle.
-As the blood flows from the atria to the ventricles, it goes through the tricuspid & bicuspid valves (also known as the atrioventricular or AV valves). These valves then snap shut, making the first heart sound (S1) or “lub” in “lub dub.” As these 2 valves snap shut, the pulmonary & aortic valves just opened. This is the beginning of systole, or contraction of the ventricles.
-As the ventricles contract, blood is pumped through the pulmonary valve (leading to the lungs) and the aortic valve (leading to the aorta & rest of the body). These valves then snap shut, making the 2nd heart sound (S2) or “dub” in “lub dub.” This is the end of systole & the beginning of diastole. At the same time, the tricuspid & bicuspid valves just opened, and the process repeats.
BLOOD FLOW THROUGH THE HEART VALVES
Blood flows from the right atrium, through the tricuspid valve to the right ventricle. Then on through the pulmonary valve to the pulmonary artery & lungs.
Pulmonary veins return blood to the left atrium, through the bicuspid (mitral) valve, to the left ventricle, and through the aortic valve to the aorta & rest of the body.
Sound confusing? Just remember “Try Performing Better Always” for the order of blood flow through the valves – Tricuspid, Pulmonary, Bicuspid, Aortic.
5 Areas for Listening to the Heart
Listening to the heart is accomplished by using five systematic locations on the anterior chest wall. These landmarks are the places on the chest where you can best hear sounds from each of the respective heart valves, even though they are not at the exact anatomic site. The stethoscope is positioned downstream from the flow of blood through the valves. Use the diaphragm of the stethoscope, switching to the bell to hear lower pitched sounds.
The Aortic valve area is on the right side at the 2nd intercostal space (ICS). The Pulmonic valve area is located on the left side at the 2nd ICS. Erb’s point is at the left 3rd ICS. The Tricuspid valve area is at the left 4th ICS, and the Mitral valve area is at the left 5th ICS at the mid-clavicular line.
*You can remember these locations using the mnemonic A-P-E-T-M: All People Enjoy Time Magazine
5 Lead EKG Placement
When placing EKG leads on a patient, proper skin preparation & electrode placement is essential for a clear EKG reading. Start by cleaning the skin briskly with an alcohol rub and allow to dry. Place electrodes in the proper placement, pressing on the outer adhesive area.
For placement, remember:
White on right, with white clouds over green grass. On the left, smoke over fire (black over red), with brown in the middle.
Causes of Heart Murmurs
Heart murmurs are audible vibrations of the heart and major vessels that occur due to turbulent blood flow. Murmurs are caused by abnormal blood flow or a structural alteration in the heart or the walls of the major vessels. Some murmurs are innocent & may disappear over time or last a lifetime without causing further health problems. Other murmurs are abnormal & more serious. You can remember the various causes of heart murmurs by remembering S.P.A.M.S.
Stenosis (narrowing) of a valve.
Partial obstruction (may be due to calcification, valve degeneration, coronary artery disease, or congenital abnormalities).
Aneurysms (in which an area of the aorta has become weak & enlarged).
Mitral or aortic regurgitation (this is when blood is leaking backward through the mitral or aortic valve – the heart has to work harder to force blood through the damaged valve & over time this can weaken or enlarge the heart, leading the heart failure).
Septal defect (hole in the septum that separates the ventricles or the atria).
Types of Heart Blocks
A heart block is an abnormal heart rhythm known as an arrhythmia and can occur anywhere in the specialized conduction system of the heart. One common area is the AV junction. The electrical signals telling the heart to contract are partially or totally blocked between the atria & ventricles – therefore it is called an atrioventricular (AV) block.
The AV blocks are identified by their severity:
Second-degree, which can be subdivided into Type 1 (Wenckebach) and Type 2 (Mobitz II).
Third-degree heart block.
What does all of this mean?
Here’s a further explanation…
First degree heart block occurs when the electrical impulses are slowed down, but they all successfully reach the ventricles. This type rarely causes problems and is often seen in highly trained athletes or as a result of some medications. On the EKG, the PR interval is >0.20 seconds, indicating a conduction delay in the AV node.
Second degree heart block exists when there is intermittent conduction failure & occurs in two varieties – Type I (also called Mobitz I or Wenckebach) & Type II (Mobitz II).
In Wenckebach, the electrical impulses are delayed further & further until conduction fails to reach the ventricles entirely. This is characterized by a P-R interval that progressively lengthens until the P wave is not followed by a QRS complex – the QRS has dropped off after the P wave.
In second-degree type II (Mobitz II), some of the electrical impulses are unable to reach the ventricles at all. The nonconducted P waves ‘can’t get through’ & may occur at random or in patterned ratios. This is much more serious & may require a pacemaker.
Third-degree heart block is a complete heart block in which none of the electrical impulses from the atria reach the ventricles and the atria & ventricles beat independently. The ventricles may generate some impulses on their own, but at a rate much slower than normal. Generally, the patient requires a permanent pacemaker.
Here’s a simple poem to help you remember the types of AV heart blocks.
“The Heart Block Poem”If the R is far from P, then you have a FIRST DEGREE.
Longer, longer, longer, drop! Then you have a WENCKEBACH.
If some Ps don’t get through, then you have MOBITZ II.
If Ps and Qs don’t agree, then you have a THIRD DEGREE.