Before We Start
Cardiac valves, heart sounds, and murmurs — the anatomy that makes sense of the sounds
The heart has four valves that act as one-way doors — opening to let blood flow forward and closing to prevent it from flowing back. Understanding where each valve sits, what it sounds like when it opens and closes normally, and what it sounds like when it malfunctions is the foundation of cardiac auscultation — one of the most important physical assessment skills in nursing.
Three mnemonics organize this territory: Toilet Paper My Ass gives you the four valve names in order. APE To Man gives you the five auscultation landmarks where you hear them best. hARD ASS MRS. MSD tells you which murmurs occur in systole and which in diastole.
💡 Systole vs Diastole — Which Valves are Open When
Systole: The ventricles are contracting — squeezing blood out. The aortic and pulmonic valves OPEN (outflow valves). The mitral and tricuspid valves CLOSE (preventing backflow into atria). S1 ("lub") is the sound of the mitral and tricuspid valves closing at the START of systole.
Diastole: The ventricles are relaxing — filling with blood from the atria. The aortic and pulmonic valves CLOSE (preventing backflow). The mitral and tricuspid valves OPEN (letting blood in). S2 ("dub") is the sound of the aortic and pulmonic valves closing at the END of systole (START of diastole).
Mnemonic 1
Toilet Paper My Ass — the four cardiac valves in order
T — Tricuspid
Right heart AV valve — between right atrium and right ventricle
The tricuspid valve has three leaflets (tri = three) and sits between the right atrium and right ventricle. It opens during diastole to let blood flow from the RA into the RV, and closes during systole to prevent backflow when the RV contracts.
When it fails — Tricuspid Regurgitation (TR): The valve does not close tightly. When the RV contracts, blood leaks back into the RA instead of all going forward to the lungs. Result: signs of right-sided HF (JVD, peripheral edema, hepatomegaly). Commonly caused by pulmonary hypertension stretching the right heart.
Murmur: Systolic murmur at the left lower sternal border — best heard when the RV is contracting (systole) and blood is regurgitating back through the incompetent valve.
P — Pulmonic
Right heart semilunar valve — between right ventricle and pulmonary artery
The pulmonic valve (pulmonary valve) sits at the outflow tract of the right ventricle — the exit door to the pulmonary artery. It opens during systole (when the RV contracts to push blood to the lungs) and closes during diastole to prevent backflow.
Pulmonic stenosis: The valve is narrowed — the RV must work harder to push blood through. More common in congenital heart disease than as an acquired condition in adults. Systolic murmur at the left upper sternal border.
Clinical note: The pulmonic valve is the least commonly affected cardiac valve in adults — most adult valve disease involves the aortic and mitral valves.
M — Mitral
Left heart AV valve — between left atrium and left ventricle — the most important valve clinically
The mitral valve (bicuspid — two leaflets) sits between the left atrium and left ventricle. It is the most clinically significant valve because the left heart handles systemic circulation at higher pressures — valve disease here has major consequences.
Mitral Stenosis (MS): The valve does not open fully — blood cannot flow freely from LA to LV. The LA enlarges under pressure → atrial fibrillation risk. Blood backs up into the lungs → pulmonary congestion. Classic cause: rheumatic fever scarring. Diastolic murmur (stenosis prevents forward flow during the filling phase).
Mitral Regurgitation (MR): The valve does not close tightly during systole — blood leaks back into the LA when the LV contracts. The LA and LV both enlarge (volume overload). Systolic murmur best heard at the apex, radiating to the left axilla. Common causes: MVP (mitral valve prolapse), rheumatic disease, MI causing papillary muscle rupture.
💊 "A-fib + dyspnea + diastolic murmur = suspect mitral stenosis." Mitral stenosis is the classic consequence of rheumatic fever. The scarred, thickened valve creates a diastolic murmur (can't open during filling) and backs up blood into the LA — enlarging it and causing atrial fibrillation. The triad of these findings should trigger echocardiogram.
A — Aortic
Left heart semilunar valve — between left ventricle and aorta — most common adult valve disease
The aortic valve sits at the LV outflow tract — the main exit of the heart into the aorta and systemic circulation. It opens during systole when the LV contracts and closes during diastole.
Aortic Stenosis (AS) — the most common valve disease in adults over 65: Calcium deposits narrow the valve — the LV must generate enormous pressure to push blood through the narrowed opening. The LV wall thickens (hypertrophy). Eventually: the LV fails. Classic triad of severe AS: syncope (faints during exertion), angina (thick LV wall outgrows its blood supply), and heart failure (the failing LV). Systolic murmur — harsh, crescendo-decrescendo, radiating to carotids.
Aortic Regurgitation (AR): The valve does not close tightly — blood leaks back into the LV during diastole. The LV becomes dilated (volume overload). Classic sign: wide pulse pressure (systolic BP much higher than diastolic — the LV fills with extra blood, generating high systolic; diastolic falls because blood leaks back). Diastolic murmur — a decrescendo blowing murmur best heard sitting forward in exhalation.
💊 "The syncope-angina-heart failure triad = severe aortic stenosis — surgery needed." Each symptom in the triad marks a different stage of AS progression. Syncope appears first (average survival 3–5 years if untreated). Angina appears second (3–5 years). Heart failure appears last (1–2 years). Once any of these symptoms appears, valve replacement is indicated — because survival without surgery is poor.
Mnemonic 2
APE To Man — five cardiac auscultation landmarks
APE To Man — in order from top to bottom, right to left
Where to place the stethoscope for each valve
The heart sounds from each valve are transmitted to the chest wall and heard best at specific landmarks — not directly over the valve itself (the valves are deep inside the chest) but at the spots where sound travels to the chest surface.
A — Aortic area: Right second intercostal space (2nd ICS), right sternal border. Best for aortic valve murmurs (both stenosis and regurgitation).
P — Pulmonic area: Left second intercostal space (2nd ICS), left sternal border. Best for pulmonic valve sounds.
E — Erb's point: Left third intercostal space (3rd ICS), left sternal border. A composite listening area where both aortic and pulmonic sounds are audible. Aortic regurgitation is often best heard here (patient sitting forward, exhaling).
T — Tricuspid area: Left fourth to fifth intercostal space (4th–5th ICS), left lower sternal border. Best for tricuspid valve sounds.
M — Mitral area (Apex): Fifth intercostal space (5th ICS), midclavicular line — the cardiac apex. Best for mitral valve sounds. S1 is loudest here. Mitral regurgitation murmur radiates to the left axilla from this position.
Memory tool: Count down from the clavicle — 2nd ICS right = Aortic, 2nd ICS left = Pulmonic, 3rd ICS left = Erb's, 4th–5th ICS left lower sternal = Tricuspid, 5th ICS midclavicular = Mitral/Apex.
💊 "All People Enjoy The Movies." Alternative memory for the order: Aortic · Pulmonic · Erb's · Tricuspid · Mitral — same sequence as APE To Man. Pick whichever sticks. What matters is being able to place the stethoscope in the right spot in a clinical assessment.
Mnemonic 3
hARD ASS MRS. MSD — systolic vs diastolic murmurs
The Murmur Timing Rule
When does the valve make noise — and why does timing matter
A murmur is caused by turbulent blood flow through an abnormal valve. The timing of the murmur — when in the cardiac cycle it occurs — tells you which type of problem the valve has:
Systolic murmurs: Occur between S1 and S2 (during ventricular contraction). Caused by:
• Semilunar valve STENOSIS (aortic or pulmonic) — the valve is narrowed, turbulence as blood is pushed through
• AV valve REGURGITATION (mitral or tricuspid) — the valve leaks backward when the ventricle squeezes
Diastolic murmurs: Occur between S2 and S1 (during ventricular filling). Caused by:
• Semilunar valve REGURGITATION (aortic or pulmonic) — blood leaks backward through the valve when the ventricle relaxes
• AV valve STENOSIS (mitral or tricuspid) — the narrowed valve restricts forward flow during filling
The hARD ASS / MRS. MSD mnemonic breakdown:
• hARD ASS: Aortic Regurgitation = Diastolic · Aortic Stenosis = Systolic
• MRS. MSD: Mitral Regurgitation = Systolic · Mitral Stenosis = Diastolic
The pattern: Regurgitation through a semilunar valve (AR, PR) = diastolic. Stenosis of a semilunar valve (AS, PS) = systolic. Regurgitation through an AV valve (MR, TR) = systolic. Stenosis of an AV valve (MS, TS) = diastolic.
💊 "If you remember nothing else: aortic stenosis = systolic murmur, mitral regurgitation = systolic murmur, aortic regurgitation = diastolic, mitral stenosis = diastolic. These are the four most tested. Know them cold and build the others from the pattern."
🏥 Clinical Scenario — Valve Assessment in Practice
During admission assessment, you auscultate the heart of three different patients. Each has a murmur. Identify the most likely valve problem for each.
Pt 1
78-year-old, syncope during gardening, history of "heart murmur for years": You hear a harsh, crescendo-decrescendo systolic murmur at the right second ICS, radiating to the neck. The carotid pulses are slow and weak. Aortic stenosis — systolic murmur at Aortic area (TPMA: A = right 2nd ICS), radiating to carotids. Syncope = severe AS triad beginning. Notify provider urgently — surgical consultation needed.
Pt 2
45-year-old woman, history of rheumatic fever as a child, progressive shortness of breath, recent onset atrial fibrillation: You hear a low-pitched, rumbling diastolic murmur best heard at the cardiac apex with the bell of the stethoscope. Mitral stenosis — diastolic murmur at Mitral area (M = 5th ICS midclavicular line). Rheumatic fever history + A-fib + dyspnea + diastolic murmur = mitral stenosis classic presentation. Echocardiogram needed.
Pt 3
55-year-old male, 3 days post-MI (anterior), new onset dyspnea: You hear a loud, blowing holosystolic (throughout systole) murmur at the cardiac apex, radiating to the left axilla. He was not noted to have a murmur on admission. New mitral regurgitation — systolic murmur at Mitral area (MRS. MSD: MR=Systolic), radiating to axilla. New post-MI mitral regurgitation can be caused by papillary muscle rupture from ischemia — a serious mechanical complication requiring urgent evaluation.
📌 NCLEX Application
Cardiac valves, heart sounds, and murmurs appear throughout NCLEX:
Valve order: "Which sequence correctly identifies the cardiac valves?" → Tricuspid · Pulmonic · Mitral · Aortic (Toilet Paper My Ass).
Murmur timing: "Which murmur occurs during systole?" → Aortic Stenosis and Mitral Regurgitation. "Which occurs during diastole?" → Aortic Regurgitation and Mitral Stenosis.
S1 and S2: "What causes S1 (the 'lub')?" → Closure of the mitral and tricuspid valves at the beginning of systole. "What causes S2 (the 'dub')?" → Closure of the aortic and pulmonic valves at the end of systole.
Auscultation landmarks: "Where does the nurse place the stethoscope to best hear mitral valve sounds?" → 5th intercostal space, midclavicular line (the cardiac apex — M in APE To Man).
⚠️ The Trap — Confusing Systolic and Diastolic Murmurs on NCLEX
Students frequently get systolic and diastolic murmur timing backwards — particularly for valves they know less well. The logic trap is thinking: "Aortic stenosis narrows the outflow — the blood flow problem is during systole when the heart is pushing out — so the murmur should be... systolic?" That logic is correct, but then the student gets confused with aortic regurgitation: "The blood is leaking back — is that systole or diastole?"
The reliable logic to build from:
• When does blood normally flow through a valve? Aortic and pulmonic valves = during SYSTOLE (outflow). Mitral and tricuspid = during DIASTOLE (filling).
• STENOSIS causes turbulence when blood SHOULD flow through → murmur during normal flow phase.
• REGURGITATION causes turbulence when blood SHOULD NOT flow through → murmur during opposite phase.
Applied:
• Aortic stenosis: aortic valve flows during systole → systolic murmur ✓
• Aortic regurgitation: aortic valve should be CLOSED during diastole, but leaks → diastolic murmur ✓
• Mitral regurgitation: mitral valve should be CLOSED during systole, but leaks → systolic murmur ✓
• Mitral stenosis: mitral valve should OPEN during diastole for filling, but is narrow → diastolic murmur ✓
✓ Quick Self-Test
Answer before checking:
1. What does "Toilet Paper My Ass" stand for?
2. What does "APE To Man" stand for and where is each landmark?
3. Which two valve problems cause systolic murmurs? Which two cause diastolic?
4. What causes S1? What causes S2?
5. A patient has the classic triad of syncope, angina, and dyspnea with a systolic murmur radiating to the carotids. What is the diagnosis?
Answers:
1. Tricuspid · Pulmonic · Mitral · Aortic — the four cardiac valves in order.
2. Aortic (right 2nd ICS) · Pulmonic (left 2nd ICS) · Erb's point (left 3rd ICS) · Tricuspid (left 4th–5th ICS lower sternal border) · Mitral/Apex (5th ICS midclavicular line).
3. Systolic murmurs: Aortic Stenosis and Mitral Regurgitation. Diastolic murmurs: Aortic Regurgitation and Mitral Stenosis. (hARD ASS MRS. MSD)
4. S1 ("lub") = closure of the mitral and tricuspid AV valves at the START of systole. S2 ("dub") = closure of the aortic and pulmonic semilunar valves at the END of systole (start of diastole).
5. Severe aortic stenosis — the classic triad of syncope + angina + heart failure (dyspnea) plus a harsh systolic murmur at the aortic area radiating to the carotids. This is the presentation that requires urgent valve replacement consultation — average survival without surgery is poor once any of the three symptoms appears.