Remembering heart murmurs comes down to organizing a handful of features into a mental framework: where to listen, when in the heartbeat the murmur occurs, what it sounds like, and how it changes with simple physical maneuvers. Once you link each valve problem to its own cluster of traits, the details stick far more easily than trying to memorize them in isolation.
Where to Listen: The APE To Man Mnemonic
The five standard listening points on the chest follow a predictable path, and the mnemonic “APE To Man” maps them from top to bottom:
- A (Aortic): Right side of the breastbone, second intercostal space (between ribs 2 and 3).
- P (Pulmonic): Left side of the breastbone, second intercostal space.
- E (Erb’s point): Left side, third intercostal space. This is where the second heart sound (S2, produced by the aortic and pulmonic valves closing together) is heard most clearly.
- T (Tricuspid): Lower left sternal border, fourth intercostal space.
- M (Mitral): The apex of the heart, fifth intercostal space at the midclavicular line (roughly below the middle of the left collarbone).
An alternative version of the same sequence is “All Patients Take Medicine,” dropping Erb’s point and covering just the four valves. Either version works. The key insight is that you start at the upper right chest and sweep down and to the left, ending at the heart’s tip.
Systolic vs. Diastolic: Timing Is Everything
Every murmur falls into one of two windows in the cardiac cycle. Systolic murmurs happen between the first heart sound (S1) and the second (S2), while the ventricles are squeezing. Diastolic murmurs happen after S2, while the ventricles are filling. Sorting murmurs by timing cuts the memorization work roughly in half.
A simple pairing trick: stenosis (narrowing) and regurgitation (leaking) produce murmurs on opposite sides of the cycle depending on which valve is affected. The aortic and pulmonic valves open during systole, so stenosis of those valves creates a systolic murmur, while their regurgitation leaks backward during diastole. The mitral and tricuspid valves work in reverse: their stenosis produces diastolic murmurs, and their regurgitation produces systolic ones. If you remember that a valve’s murmur appears when it should be doing its job but can’t do it properly, the timing makes intuitive sense.
Recognizing an Innocent Murmur: The 7 S’s
Not every murmur signals a problem. Innocent (benign) murmurs are extremely common, especially in children. A mnemonic called the 7 S’s captures the features that point toward a harmless murmur:
- Systolic
- Soft (quiet, below grade 3)
- Small (doesn’t radiate to other areas)
- Short (not lasting the entire systolic phase)
- Single (no extra heart sounds or clicks accompanying it)
- Sweet (musical or vibratory quality, not harsh)
- Sensitive (changes with body position)
If a murmur checks all seven boxes, it is far more likely to be benign. Any feature that breaks the pattern, like a diastolic component, harsh quality, or loud intensity, raises concern.
Grading Loudness: The 6-Point Scale
Murmurs are graded on a scale of 1 to 6, and the critical dividing line to remember is between grades 3 and 4. That’s where a “thrill” appears: a vibration you can feel with your hand on the chest.
- Grade 1: Faint, barely audible even in a quiet room.
- Grade 2: Soft but clearly heard with a stethoscope.
- Grade 3: Easily audible, no thrill.
- Grade 4: Easily audible with a palpable thrill.
- Grade 5: Audible with the stethoscope barely touching the chest, thrill present.
- Grade 6: Audible with the stethoscope lifted off the chest entirely.
The memory shortcut: grades 1 through 3 are “hear only,” grades 4 through 6 are “hear and feel.” A grade 4 or higher murmur is almost always pathologic.
Sound Quality and Radiation Patterns
Each classic murmur has a signature sound and a direction it travels, which together form a recognizable fingerprint.
Aortic stenosis produces a harsh, crescendo-decrescendo (diamond-shaped) systolic murmur best heard at the aortic area. It radiates up into the carotid arteries in the neck. Think of blood being forced through a narrowed exit and shooting upward toward the head.
Mitral regurgitation is a high-pitched, blowing systolic murmur loudest at the apex. It radiates toward the left armpit (axilla). This makes anatomical sense: the left ventricle sits in front of the left atrium, so a backward jet of blood through a leaky mitral valve flows posteriorly and laterally, carrying the sound with it.
Mitral stenosis produces a low-pitched, rumbling diastolic murmur at the apex. It is often described as sounding like a distant thunder roll and is best heard with the bell of the stethoscope while the patient lies on their left side.
Aortic regurgitation is a soft, blowing, decrescendo diastolic murmur heard along the left sternal border. Because the leaking happens right after the aortic valve closes, the murmur starts loud and tapers off as the pressure difference shrinks.
Linking each murmur to its radiation pattern gives you a second way to identify it, even if the sound quality is ambiguous. Radiation to the neck points to the aortic valve; radiation to the armpit points to the mitral valve.
Dynamic Maneuvers: The Exam Favorite
Certain physical maneuvers change blood flow in predictable ways, making some murmurs louder and others quieter. Two conditions respond in a unique, almost opposite pattern compared to everything else: hypertrophic obstructive cardiomyopathy (HOCM) and mitral valve prolapse (MVP). Remembering how these two behave is the key to nearly every exam question on this topic.
Valsalva Maneuver (Bearing Down)
Bearing down against a closed airway raises pressure inside the chest. This reduces the amount of blood returning to the heart, which shrinks the left ventricle. A smaller ventricle makes the obstruction in HOCM worse, so the HOCM murmur gets louder. MVP also gets louder because the prolapse happens earlier when there is less blood to keep the valve leaflets in place. Most other murmurs, including aortic stenosis, mitral regurgitation, and tricuspid stenosis, get quieter because there is simply less blood flowing across the abnormal valve.
Squatting
Squatting does the opposite of Valsalva. It increases blood return to the heart and simultaneously raises the resistance the left ventricle pumps against. More blood filling the ventricle reduces the obstruction in HOCM, making that murmur quieter. MVP also quiets down. Meanwhile, most other murmurs, including aortic stenosis, aortic regurgitation, mitral regurgitation, and mitral stenosis, get louder because there is more blood flowing through the affected valve.
Isometric Handgrip
Sustained handgrip (squeezing something hard for 30 seconds or more) raises the resistance in your arteries. This makes it harder for blood to leave the left ventricle, which reduces the HOCM obstruction and quiets that murmur. It also quiets aortic stenosis and MVP. But murmurs driven by regurgitation, like mitral regurgitation and aortic regurgitation, get louder because the higher resistance pushes more blood backward through the leaky valve.
The Pattern to Remember
HOCM and MVP are the rebels. Whatever makes most murmurs louder (squatting, handgrip) makes HOCM and MVP quieter, and whatever makes most murmurs quieter (Valsalva, standing) makes HOCM and MVP louder. If you remember “HOCM and MVP move in the opposite direction,” you can reason through any maneuver question without pure memorization.
Putting It All Together
Rather than memorizing a giant table, build each murmur as a story with four elements: location, timing, sound, and behavior. For example, aortic stenosis lives at the upper right chest, happens in systole, sounds harsh and diamond-shaped, radiates to the neck, and gets quieter with Valsalva. That five-part profile is far easier to recall than disconnected facts because each piece reinforces the others.
Practice by working through murmurs in pairs of opposites. Aortic stenosis (systolic, harsh, radiates to neck) naturally contrasts with aortic regurgitation (diastolic, blowing, heard along the left sternal border). Mitral regurgitation (systolic, blowing, radiates to armpit) contrasts with mitral stenosis (diastolic, rumbling, stays at the apex). These contrasts reinforce both sides at once.
Finally, use the 7 S’s as a quick filter whenever you encounter a murmur on paper or in practice. If every S is satisfied, the murmur is likely innocent. If even one feature breaks the pattern, work through your mental profiles to match it to a specific valve lesion.