Systolic Murmurs Range from Innocent Flow Sounds to Severe Valve Disease. Ejection Versus Regurgitant Timing Is the First Distinction.

What It Is

The Murmur: Sound Produced by Turbulent Flow

A murmur is an abnormal sound produced by turbulent blood flow. Normal laminar blood flow through the heart and vessels is silent. Turbulence generates audible vibrations. Turbulence is caused by:

• Increased flow velocity through a normal orifice (physiologic/innocent murmurs)
• Flow through a narrowed orifice (stenosis)
• Flow backward through an incompetent valve (regurgitation)
• Flow through an abnormal communication between chambers (septal defect)

Systolic murmurs occur during systole, the period when the ventricles contract. On the ECG, systole spans from the QRS complex to the end of the T wave. In auscultation, systole is the interval between the first heart sound (S1, the “lub”) and the second heart sound (S2, the “dub”).

Ejection Murmurs vs Regurgitant Murmurs

The two categories of systolic murmur have different timing, character, and clinical implications:

Ejection (systolic) murmurs: Begin after S1 (there is a brief gap of silence after S1 before the murmur starts), crescendo to a peak, and decrescendo before S2 (diamond-shaped on phonocardiogram). They arise from flow across the aortic or pulmonic outflow tract and include aortic stenosis, aortic sclerosis, hypertrophic cardiomyopathy (HCM), and pulmonic stenosis.

Holosystolic (pan-systolic) murmurs: Begin with S1 and persist uniformly throughout all of systole, ending at S2. They arise from regurgitant flow through an incompetent atrioventricular valve or through a ventricular septal defect. They include mitral regurgitation, tricuspid regurgitation, and VSD.

Late systolic murmurs: Begin after a midsystolic click and persist to S2. Classic for mitral valve prolapse (MVP).

This timing distinction has clinical implications: holosystolic murmurs in adults are almost always pathological. Ejection murmurs may be physiologic (innocent flow murmur) or pathological (aortic stenosis).

Levine Grading Scale

The Levine scale grades murmur intensity from 1 to 6:

A “thrill” is a palpable vibration over the precordium, corresponding to a grade 4 or higher murmur. Grades 4 to 6 are consistently pathological. Grades 1 to 2 may be innocent. Grade 3 is the clinical ambiguity zone where character, location, and dynamic maneuvers matter most.

Murmur intensity does not reliably correlate with severity of disease. A grade 2/6 aortic stenosis murmur in a patient with severely reduced cardiac output (low-flow, low-gradient AS) may represent critical stenosis, while a grade 4/6 murmur in a high-output state may be physiologic. Grade alone is insufficient for clinical decision-making.

The Mechanism

Aortic Stenosis

The most clinically important systolic ejection murmur in adults is aortic stenosis (AS). AS occurs when the aortic valve leaflets become thickened, calcified, and restricted in motion, reducing the effective orifice area for left ventricular outflow.

Normal aortic valve area: 3 to 4 cm2.

• Mild AS: 1.5 to 3.0 cm2
• Moderate AS: 1.0 to 1.5 cm2
• Severe AS: < 1.0 cm2
• Very severe AS: < 0.6 cm2

The mechanism of stenosis in most adults is calcific aortic valve disease, the same degenerative process that causes coronary artery disease, driven by lipid deposition, inflammation, and calcification 5 / Solid 69208-9). Risk factors overlap substantially with CAD: hypertension, diabetes, hyperlipidemia, smoking. Bicuspid aortic valve (BAV), present in approximately 1 to 2 percent of the population, accelerates this process by two to three decades; severe AS in a 40-year-old should raise suspicion for BAV.

The murmur of aortic stenosis is a harsh, crescendo-decrescendo ejection murmur at the right upper sternal border (second intercostal space, right), radiating to the neck (carotid arteries). The peak of the murmur shifts later in systole as stenosis worsens: the later the peak, the more severe the gradient. The Gallavardin phenomenon describes the high-pitched component of a severe AS murmur that can be transmitted to the apex and mistaken for mitral regurgitation.

Hypertrophic Cardiomyopathy (HCM)

HCM produces a dynamic systolic ejection murmur that increases with maneuvers that decrease preload (standing, Valsalva) and decreases with maneuvers that increase preload (squatting, passive leg raise). This dynamic quality distinguishes HCM from fixed aortic stenosis.

The HCM murmur arises from dynamic left ventricular outflow tract obstruction (LVOTO): the hypertrophied interventricular septum and the systolic anterior motion (SAM) of the mitral valve apparatus create dynamic obstruction that worsens as the LV cavity size decreases. The murmur is loudest at the left lower sternal border and does not radiate prominently to the neck 5 / Solid .

HCM is the most common cause of sudden cardiac death in young athletes. A systolic murmur in a young, athletic patient that increases with standing deserves urgent echocardiography and specialist evaluation.

Mitral Regurgitation

Mitral regurgitation (MR) produces a holosystolic murmur at the cardiac apex, radiating to the left axilla. It is uniform throughout systole (no crescendo-decrescendo pattern), high-pitched (“blowing”), and often associated with a displaced and forceful apical impulse in chronic severe MR (because the LV is volume-overloaded and enlarged).

Causes of MR vary by age:

• Young patients: mitral valve prolapse (most common cause in the US)
• Middle age: degenerative MR from leaflet thickening and chordal elongation
• Older adults: calcific annular disease, ischemic MR from papillary muscle dysfunction
• Any age: endocarditis, rheumatic disease (in populations where rheumatic fever is prevalent)

The Carpentier functional classification of MR distinguishes normal leaflet motion (Type I, e.g., annular dilation), leaflet prolapse (Type II), and restricted leaflet motion (Type III, e.g., rheumatic).

Tricuspid Regurgitation

Tricuspid regurgitation (TR) produces a holosystolic murmur at the left lower sternal border, louder with inspiration (Carvallo’s sign, because increased venous return increases right heart flow during inspiration). It is often accompanied by prominent jugular venous pulsations, a pulsatile liver, and peripheral edema in significant TR.

Functional (secondary) TR from right ventricular dilation is more common than primary TR from leaflet pathology. Secondary TR often accompanies left-sided heart disease (mitral disease, heart failure with pulmonary hypertension).

Ventricular Septal Defect

A congenital VSD produces a holosystolic murmur at the left lower sternal border, harsh, and potentially accompanied by a thrill. Small VSDs (the “maladie de Roger”) produce loud murmurs from high-pressure turbulence; large VSDs in adults with Eisenmenger physiology (equalized LV-RV pressures) may paradoxically produce no murmur because there is no significant pressure gradient.

How We Diagnose / How It Is Used

Dynamic Auscultation Maneuvers

Dynamic maneuvers are physical changes that alter preload, afterload, or heart rate, and by doing so change the hemodynamic conditions that produce each murmur. They are the most powerful tool available to the cardiologist at the bedside for differentiating one systolic murmur from another before echocardiography.

The key clinical application: a murmur that is louder with standing and quieter with squatting is almost always HCM. A murmur that is louder after a premature beat (post-extrasystolic potentiation) is consistent with outflow obstruction (AS or HCM). A murmur that remains unchanged with all maneuvers is more consistent with MR or TR.

The Etchells 1997 JAMA study validated clinical examination for murmur diagnosis: a standing-to-squatting increase in murmur for HCM had sensitivity 88 percent and specificity 92 percent; radiation to the carotid arteries for AS had LR+ 7.5 5 / Solid .

When to Order an Echocardiogram

The echocardiogram (transthoracic echocardiogram, TTE) is the standard diagnostic tool for murmur evaluation. It provides:

• Direct visualization of valve morphology (leaflet number, thickening, calcification, prolapse)
• Hemodynamic quantification: peak velocity, mean gradient, valve area (by continuity equation), EROA (effective regurgitant orifice area)
• Left ventricular function and dimensions
• Right-sided pressure estimation
• Pericardial assessment

The 2014 AHA/ACC Valve Guideline recommendation: echocardiography is indicated for any patient with a new murmur in whom the clinical diagnosis is not clear, in any patient with a grade 3 or louder murmur without an obvious benign explanation, and in any patient with symptoms that might be attributable to valve disease 5 / Solid .

Not every murmur requires echocardiography. A 25-year-old with a grade 1 to 2 vibratory ejection murmur at the left sternal border that disappears with standing, in the setting of a fever or anemia, likely has a physiologic flow murmur and does not require immediate imaging. This clinical distinction requires clinical judgment, which is the argument for cardiology or internal medicine review before automatic echocardiogram ordering.

Auscultation Accuracy: What the Evidence Says

How accurate is the stethoscope? The honest answer is: less accurate than cardiologists sometimes believe, but better than internists under real-world conditions.

Etchells 1997 found that cardiologists correctly identified the murmur etiology based on auscultation alone 75 to 80 percent of the time in a controlled academic setting 5 / Solid . In community primary care settings, accuracy is lower, partly because most primary care physicians auscultate far fewer murmurs per year than a cardiologist, and the skill of hearing the timing, character, and dynamic response of a murmur degrades without practice.

Artificial intelligence-assisted digital stethoscopes (Eko, Stethoscope by Eko, FDA-cleared De Novo device) can analyze recorded heart sounds and flag patterns consistent with AS or MR with sensitivity above 80 percent in published studies 4 / Promising . These devices do not replace echocardiography; they may improve the yield of echocardiogram referrals from primary care by reducing missed murmurs.

The Evidence

Prevalence and Natural History of Key Systolic Murmur Causes

Aortic stenosis: Affects 2 to 3 percent of adults over 65 and 4 percent over 85 5 / Solid 69208-9). Severe AS has a well-characterized natural history after symptom onset: the classical triad of angina (average survival 5 years without intervention), syncope (3 years), and heart failure (1 to 2 years). Intervention is indicated at symptom onset or when aortic velocity exceeds 5 m/s (very severe) 5 / Solid .

Mitral regurgitation: Primary (degenerative) MR affects approximately 2.5 percent of the US population 5 / Solid . Severe primary MR carries a 10-year mortality of 20 to 30 percent with medical management and increasing risk of atrial fibrillation, LV dysfunction, and pulmonary hypertension 5 / Solid . Early surgery (before LV dysfunction, EF < 60% or LVESD > 40 mm) is associated with better outcomes than waiting for symptoms.

HCM: Prevalence approximately 1 in 500 in the general population 5 / Solid . Annual sudden death risk in unselected HCM patients is 0.5 to 1 percent per year; in high-risk patients with multiple risk factors, annual risk is 3 to 5 percent. ICD therapy is indicated for high-risk patients.

The Patient Experience

Being Told About a Murmur

The experience of being told about a murmur at a routine appointment is, for many patients, deeply disorienting. The visit began as a wellness check. It ended with a referral to cardiology and an echocardiogram order.

What patients most commonly need at this moment is not reassurance that “it’s probably nothing.” They need specific information: a murmur is a sound produced by blood flow across a valve. The echocardiogram will look at the valve’s structure and function to determine whether this sound represents anything that needs treatment. Most murmurs discovered incidentally in otherwise healthy adults do not require treatment. Some do. The echocardiogram is how we find out which category you are in.

This is a two-minute conversation that substantially reduces anxiety while remaining clinically honest. It replaces the vague dismissal (“it’s probably fine, don’t worry”) that leaves patients researching heart disease at midnight with the worse versions they find online.

The Athlete with a Murmur

Competitive athletes with systolic murmurs require specific evaluation. Dynamic ejection murmurs in athletes are common and frequently physiologic (high cardiac output increases turbulence). However, HCM and congenital aortic stenosis, both present in young athletes, require identification because they carry sudden death risk under exertion.

The American Heart Association’s 12-element preparticipation screening recommendation includes auscultation specifically to detect murmurs that might indicate HCM or other structural heart disease 5 / Solid . A murmur that increases with standing in an athlete requires echocardiography before return to competitive sport.

The Murmur Found in Pregnancy

Pregnancy increases cardiac output by 30 to 50 percent. Physiologic flow murmurs are nearly universal in pregnant women by the second trimester. Most are innocent. Distinguishing a pregnancy-related flow murmur from a pre-existing structural murmur (mitral valve disease, aortic stenosis, HCM) requires clinical assessment and, when uncertain, echocardiography.

Severe valvular disease in pregnancy carries significant maternal and fetal risk. Referral to a cardio-obstetrics program is appropriate for pregnant women with any murmur that is not clearly physiologic.

Decisions and Trade-Offs

When to Refer to Cardiology vs. Follow-Up in Primary Care

For murmurs that are clearly grade 1 to 2 and physiologic in character (vibratory, not holosystolic, varying with position), primary care follow-up without immediate cardiology referral is reasonable. For murmurs that are grade 3 or louder, holosystolic, associated with symptoms (dyspnea, exertional presyncope, syncope), or in patients with a family history of sudden cardiac death or HCM, cardiology referral is indicated.

For elderly patients (over 70) with an asymptomatic harsh systolic ejection murmur at the right upper sternal border, the probability that this represents at least moderate aortic stenosis is high enough that direct echocardiography referral, not just cardiology referral, is appropriate.

Watchful Waiting vs Repair: The Timing Problem in Valve Disease

Valve surgery (or transcatheter valve intervention) is not always immediately indicated when a significant murmur is identified. The current guidelines for AS and MR specify exact thresholds based on echocardiographic parameters and symptom status.

The risk of waiting too long: LV dysfunction (in AS: afterload mismatch leading to reduced EF; in MR: volume overload leading to LV dilation) becomes irreversible if intervention is delayed past certain thresholds. The risk of acting too early: surgery or transcatheter intervention carries procedural risk, and unnecessary early intervention subjects a patient to procedural risk without benefit.

Echocardiographic surveillance intervals for moderate AS (every 1 to 2 years) and moderate-to-severe MR (every 6 to 12 months) are designed to catch the transition to the intervention threshold before irreversible damage occurs 5 / Solid .

TAVR vs SAVR: What the Murmur Patient May Eventually Face

For patients who progress to severe symptomatic AS, the choice between transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) is driven by surgical risk, anatomy, age, and patient preference. The PARTNER 3 and EVOLUT Low Risk trials established TAVR as non-inferior to SAVR in low-surgical-risk patients for 5-year outcomes 5 / Solid . TAVR is now the preferred approach for patients over 65 and a shared-decision discussion for those between 55 and 65.

This is relevant to the patient in the opening scene: a 45-year-old woman who has a murmur today, turns out to have moderate aortic stenosis, and is surveilled for fifteen years may eventually face this conversation.

Clinical Synthesis

The systolic murmur is one of the most common incidental findings in cardiology, and it is one of the most consistently under-investigated in primary care settings. Patients are frequently told a murmur “sounds innocent” without echocardiographic confirmation, and significant valvular disease is missed until symptoms develop, sometimes too late for the ideal intervention window.

In the Chicago metropolitan area, Northwestern Medicine’s Bluhm Cardiovascular Institute and the University of Chicago Medicine Valve Center both have dedicated structural heart and valve clinics. Carle Foundation Hospital in Urbana has echocardiography and structural heart referral capability. For patients in rural central Illinois, OSF Saint Francis Medical Center in Peoria is the regional structural heart center.

The woman in the opening scene who left her primary care appointment anxious and without answers deserves a system that converts that anxiety into a specific plan within days, not weeks. The Signal Check is designed to be that system.

Aortic Stenosis in Depth: The Progression Curve Every Patient Needs to Understand

The diagnosis of aortic stenosis does not sit still. It moves. Every year, the aortic valve area in a patient with moderate-to-severe AS decreases by approximately 0.1 cm² 5 / Solid . Every year, the mean gradient across the valve increases by 7 mmHg on average. These are population averages, and individual patients vary considerably, but the trajectory is almost always unidirectional. Aortic stenosis does not improve without intervention.

This matters for the patient sitting across from you who has been told: “Your valve looks pretty tight, but you do not have symptoms yet, so we will keep watching it.” That conversation, if it ends there, is incomplete. “Watching it” without a defined schedule, a defined threshold, and a defined escalation plan is not watchful waiting. It is deferral.

The Asymptomatic Severe AS Problem

Approximately 40 percent of patients with severe aortic stenosis are asymptomatic at any given point in their clinical course 5 / Solid . For decades, the practice guideline position was clear: wait for symptoms. The reasoning was that the operative mortality of aortic valve replacement was not trivially low (1 to 3 percent in major centers, higher at lower-volume hospitals), and the hazard ratio favoring early intervention did not justify the procedural risk in asymptomatic patients.

The AVATAR trial, published in 2021, began to shift that calculus. It enrolled 157 patients with asymptomatic severe AS (valve area ≤1.0 cm², mean gradient ≥40 mmHg, preserved LVEF ≥50%) and randomized them to early surgical AVR versus conservative management with standard-of-care. At a median follow-up of 32 months, the primary endpoint (composite of all-cause death, MI, stroke, or HF hospitalization) occurred in 15 percent of the early surgery group versus 35 percent of the conservative management group (HR 0.46; 95% CI 0.23-0.90) 4 / Promising . The trial was underpowered by design, but the directional signal was the strongest it has been.

The RECOVERY trial, conducted in South Korea, enrolled 145 patients and randomized to early AVR versus conventional treatment with lower-risk operative criteria (a high-volume academic center population). After a mean follow-up of 6 years, operative mortality after early surgery was 1 percent, and the 6-year cumulative incidence of death was 7 percent in the early-surgery group versus 21 percent in the conservative group 4 / Promising .

These trial results created the foundation for the 2021 ACC/AHA valvular heart disease guideline update, which gave a Class IIa recommendation for AVR in asymptomatic patients with very severe AS (Vmax ≥5 m/s) and low surgical risk. The clinical implication: the era of waiting indefinitely for symptoms is ending.

The Symptom Triad and Its Timing

When AS does produce symptoms, the sequence predicts survival. Angina in AS occurs first, most commonly from increased oxygen demand in the hypertrophied LV combined with reduced coronary reserve, and sometimes from coexistent coronary artery disease. After the onset of angina, mean survival without intervention is approximately 5 years 5 / Solid . Syncope or near-syncope from AS carries a 3-year mean survival without intervention. Heart failure from AS, the final stage of the symptom triad, carries a mean survival of 1 to 2 years without AVR.

This progression is not academic. The patient who says “I just get a little short of breath on the stairs” after having been told last year that she was asymptomatic has not crossed a vague clinical line. She has crossed a survival line. That shortness of breath, if it is attributable to AS, places her in the HF symptom category with its 1 to 2 year natural history trajectory. The interval between first symptoms and intervention determines whether she presents to surgery with preserved LVEF and a healthy LV or with a dilated, decompensated ventricle.

TAVR and the Democratization of Valve Replacement

For most of the 20th century, aortic valve replacement required open heart surgery, cardiopulmonary bypass, and a sternotomy. The procedure was effective but carried real procedural risk, and older patients or those with severe comorbidities were often deemed inoperable.

Transcatheter aortic valve replacement (TAVR) changed that architecture. The PARTNER trial, first published in 2010, showed that TAVR was superior to medical management in patients who were not surgical candidates (10.1056/NEJMoa1008232). PARTNER 1A showed non-inferiority to surgery in high-risk patients. Over the next decade, the technology was tested progressively in lower-risk populations.

PARTNER 3 enrolled 1,000 low-risk patients (STS score ≤4%) and randomized them to TAVR with the SAPIEN 3 valve versus surgical AVR. At 2 years, TAVR was non-inferior to surgery on the primary composite endpoint of death, stroke, or rehospitalization (8.5% vs 15.1%; rate ratio 0.54; 95% CI 0.37-0.79) 5 / Solid . The EVOLUT Low Risk trial with the Medtronic Evolut valve showed similar results.

The practical implication for a 70-year-old patient in Champaign-Urbana who is told she has severe symptomatic AS: TAVR is now the standard of care for most patients over 65 with suitable valve anatomy. The procedure is performed via a catheter through the femoral artery, typically under conscious sedation or light general anesthesia, and patients often go home the next day. At Carle Foundation Hospital in Urbana, a structural heart program with echocardiographic guidance supports TAVR workup and case selection, with procedural volume at regional centers increasing year over year.

Northwestern Medicine Bluhm Cardiovascular Institute and Rush University Medical Center in Chicago are among the highest-volume TAVR centers in Illinois, with a Heart Team model that includes cardiac surgery, interventional cardiology, imaging, and anesthesia. For patients in rural central Illinois, OSF Saint Francis Medical Center in Peoria has a dedicated structural heart program with TAVR capability.

Valve Choice, Durability, and Age-Based Decision-Making

When a patient with severe AS is younger than 50, or is 55 and is a vigorous, high-functioning person who may live 30 more years, the valve choice decision requires honest discussion. Bioprosthetic valves (bovine pericardium or porcine) do not require anticoagulation but degenerate over time. In younger patients (under 60), structural valve deterioration rates requiring reintervention at 15 to 20 years are substantial. Mechanical valves are more durable but require lifelong warfarin anticoagulation.

The NOTION trial, which randomized patients 70 and older to TAVR versus SAVR and followed them for 5 years, showed no significant difference in structural valve deterioration between the transcatheter and surgical bioprosthetic valves 4 / Promising . But this was a 70-and-older population. In younger patients, the durability question is live.

The concept of “valve-in-valve TAVR” partially resolves this. When a surgical bioprosthesis fails, a second TAVR device can be deployed inside the failed valve without reoperation. This has changed the valve choice conversation: a bioprosthetic surgical valve at age 55, managed through valve-in-valve TAVR at 75, may be a coherent long-term strategy. But the hemodynamic outcomes of nested valves are not identical to primary valve replacement, and the long-term durability data for double-nested valves does not yet exist at scale 3 / Early .

The cardiologist’s responsibility in this conversation is not to pick a valve for the patient. It is to explain the decision clearly enough that the patient can make their own choice with full information. That conversation takes time. Most 15-minute office visits do not contain it.

Hypertrophic Cardiomyopathy: Beyond the Murmur

HCM deserves separate attention because the murmur is often the first and only clinical finding, and the stakes of missing or mismanaging it are high. The prevalence of HCM in the general population is approximately 1 in 500 5 / Solid . Most patients never develop symptoms severe enough to limit their lives. But a meaningful subset does, and a small but critical subset is at risk for sudden cardiac death.

The HCM murmur is systolic, crescendo-decrescendo, heard best at the left lower sternal border with variable radiation. Its defining characteristic is dynamic variation: the murmur increases with maneuvers that decrease LV volume (standing, Valsalva) and decreases with maneuvers that increase it (squatting, passive leg raise). This dynamism reflects the outflow tract obstruction that varies with loading conditions.

Genetic testing has changed how we think about HCM families. Pathogenic variants in MYH7 (beta-myosin heavy chain) and MYBPC3 (myosin binding protein C) together account for approximately 70 percent of genotype-positive HCM 5 / Solid . When a proband is identified with HCM, cascade genetic screening of first-degree relatives is now a Class I guideline recommendation, enabling identification of mutation carriers before they develop clinical disease or experience an event.

The HCM murmur is not just a physical examination finding. It is the entry point into a family conversation that may identify an undiagnosed sibling, a college-age son preparing to walk onto a basketball court, or a grandmother with unexplained dyspnea attributed to “old age.” A structured cardiovascular assessment framework was designed to catch exactly this pattern: a clinical finding in one patient that, when followed systematically, protects the people around them.

Access Gaps and the Structural Heart Referral Failure

Not every systolic murmur patient gets referred. Not every referral results in a timely echocardiogram. Not every echocardiogram result gets communicated with the context the patient needs to act on it.

A 2019 analysis published in JAMA Cardiology found that among patients with at least moderate-severe AS who met guideline criteria for referral to a valve clinic, fewer than 50 percent had documentation of a valve clinic referral in the preceding 12 months 5 / Solid . The gap was larger in rural areas and in non-academic medical centers.

There is a separate access gap along racial and ethnic lines. Black patients with severe AS undergo AVR at lower rates than White patients after adjustment for age, sex, and comorbidity 4 / Promising . The mechanism is likely multifactorial: referral patterns, patient hesitation shaped by historical medical mistreatment, procedural gatekeeping, and structural barriers to reaching high-volume centers. In a disease where delayed intervention predicts excess mortality, this disparity translates directly into years of life.

The systolic murmur is a sound. The sound is data. The question is what the clinical system does with that data after the stethoscope is placed on the chest. In a functional system, the data triggers a workflow: echo within 30 days, result reviewed with the patient, referral generated if thresholds are met, follow-up appointment confirmed. In the current U.S. healthcare system, that workflow exists in some practices and is entirely absent in others. The patient does not know which system she has walked into until the outcome arrives.

Mitral Regurgitation: The Murmur That Hides Its Damage Until It Is Too Late

Mitral regurgitation produces a holosystolic murmur at the apex with radiation to the axilla. It is among the most common valvular abnormalities found on echocardiography in the United States, present in some degree in an estimated 2 to 10 percent of the adult population depending on severity thresholds 5 / Solid . Mild MR found incidentally on an echocardiogram ordered for another reason rarely requires more than documentation. Moderate-to-severe MR is a different matter, and the failure to distinguish the two is one of the most common valvular management errors in primary care.

The Two-Disease Model of Mitral Regurgitation

Mitral regurgitation is not one disease. It is two, with different mechanisms, different natural histories, and different surgical strategies.

Primary MR (previously called organic or degenerative MR) arises from intrinsic disease of the mitral valve apparatus: the leaflets, the chordae tendineae, or the papillary muscles. The most common cause in the United States is mitral valve prolapse (MVP), present in approximately 2 to 3 percent of the general population. In MVP, one or both leaflets bulge posteriorly past the mitral annular plane during systole, producing incomplete coaptation and regurgitation. The Barlow variety involves thick, redundant leaflets with widespread prolapse; the fibroelastic deficiency variety involves thin, translucent leaflets that rupture a chorda without much warning, producing acute severe MR.

Secondary MR (previously called functional or ischemic MR) arises from disease of the left ventricle, not the valve itself. The valve leaflets are often anatomically normal; the regurgitation occurs because ventricular dilation or regional wall motion abnormality from prior MI displaces the papillary muscles, tethering the leaflets and preventing full coaptation. In secondary MR, the target of treatment is the LV, not the valve. This distinction has direct implications for surgical decisions, and confusing the two has led to unnecessary mitral surgeries in patients with secondary MR who do not benefit 5 / Solid .

The LV Compensation Trap

The reason MR destroys ventricles silently for years is that the LV initially tolerates the volume overload well. When the mitral valve leaks during systole, blood flows backward into the low-pressure left atrium rather than forward into the high-pressure aorta. The LV faces a reduced afterload. Cardiac output appears maintained. The patient feels fine.

Over years, the chronic volume load causes eccentric LV hypertrophy (dilation and wall thickening to maintain wall stress). The LV dilates progressively. Contractility is preserved by the Frank-Starling mechanism for a long period. By the time the ejection fraction begins to fall, significant and potentially irreversible myocardial damage has already occurred.

This is the clinical trap: an LVEF of 60 percent in a patient with severe primary MR does not mean normal LV function. In a patient without MR, the LV ejects against full systemic resistance; an EF of 60 percent reflects normal contractility. In a patient with severe MR, the LV ejects into both the aorta and the low-resistance left atrium, making the effective afterload artificially low. An LVEF of 60 percent in severe MR may actually reflect subnormal contractile reserve. The current guideline threshold for intervention is LVEF ≤60% or LV end-systolic dimension (LVESD) ≥40 mm 5 / Solid . These thresholds exist precisely because waiting for symptomatic LV failure means waiting too long.

Mitral Repair Versus Replacement

When primary MR reaches the intervention threshold, repair is almost always preferred over replacement. Mitral valve repair preserves the subvalvular apparatus, maintains normal LV geometry, and avoids the need for anticoagulation associated with mechanical prostheses. At experienced centers, repair rates for degenerative MR exceed 95 percent, with durability exceeding 90 percent freedom from reoperation at 10 years 5 / Solid .

The problem is volume-outcome relationships. The mitral repair rates at community hospitals doing fewer than 25 mitral operations per year are significantly lower than at high-volume centers. A patient who receives a mitral replacement when repair was feasible has a prosthesis for the rest of their life, with all attendant risks: anticoagulation, prosthetic valve endocarditis, structural deterioration, and eventually the need for reoperation or transcatheter reintervention.

The Society of Thoracic Surgeons database analysis showed that for isolated mitral valve surgery, annual institutional volume above 25 cases per year is associated with significantly lower operative mortality and higher repair rates 5 / Solid . This creates a direct geographic equity problem: patients in rural Illinois who are referred to their nearest community hospital rather than to a high-volume center in Chicago, Peoria, or St. Louis are receiving structurally inferior care not because of clinical factors but because of where they live.

At Carle Foundation Hospital in Urbana, mitral surgery is performed with referral collaboration with high-volume academic partners. For patients with complex mitral disease requiring repair, referral to Northwestern Medicine Bluhm Cardiovascular Institute or University of Chicago Medicine provides access to mitral repair expertise. This referral decision should be made before the patient deteriorates, not after.

The MitraClip and Transcatheter Mitral Options

For patients with secondary MR who are poor surgical candidates, the MitraClip (Abbott) device provides a transcatheter option. The COAPT trial enrolled 614 patients with heart failure, LVEF 20 to 50 percent, and moderate-to-severe secondary MR despite guideline-directed medical therapy. At 2 years, the MitraClip group had lower all-cause mortality (29% vs 46%, HR 0.62; 95% CI 0.46-0.82), lower HF hospitalizations (35.8% vs 67.9% at 24 months), and improved quality of life 5 / Solid .

The MITRA-FR trial, also examining MitraClip in secondary MR, showed no benefit 4 / Promising . The discrepancy between COAPT and MITRA-FR is explained at least partly by patient selection: COAPT enrolled patients with more severe and “proportionate” MR relative to LV size, while MITRA-FR included more patients with severe LV dilation where the MR may have been a bystander rather than the primary driver of HF.

The lesson: MitraClip is not for every heart failure patient with secondary MR. It is for the patient in whom the secondary MR is the primary driver of symptoms and hemodynamic compromise, not simply a marker of a dilated, failing LV. Distinguishing these patients requires detailed echocardiographic analysis and heart failure subspecialty input.

The Physical Examination in 2026: Still Necessary, Increasingly Supported

The stethoscope has existed as a clinical tool since Rene Laennec’s 1816 description of the rolled paper cylinder applied to a patient’s chest at the Necker Hospital in Paris. Two hundred years later, debate continues about whether the physical examination of the heart remains clinically useful in an era when echocardiography is readily available.

The answer is: yes, but with caveats that practicing clinicians need to understand clearly.

What the Stethoscope Gets Right

Experienced cardiologists can identify moderate-to-severe aortic stenosis by auscultation with sensitivity and specificity exceeding 70 to 80 percent 5 / Solid . The combination of a harsh crescendo-decrescendo murmur, delayed carotid upstroke (pulsus parvus et tardus), and a single S2 carries a likelihood ratio for severe AS that rivals many ECG findings.

For the detection of any cardiac murmur requiring further evaluation, a careful 2-minute cardiac examination remains the most cost-effective screening tool available in any clinical setting globally. This matters in Champaign-Urbana, where echocardiography is accessible within days at Carle Foundation Hospital. It matters dramatically more in rural sub-Saharan Africa, where the same stethoscope in an experienced hand is the only diagnostic tool available and has been shown to detect rheumatic valvular disease at comparable rates to echocardiographic screening programs when the examiner is trained 3 / Early .

What the Stethoscope Gets Wrong

The stethoscope underperforms consistently for mild-to-moderate disease. In a systematic review of clinician ability to detect valvular disease by auscultation alone, sensitivity for mild-to-moderate MR was 54 percent among internal medicine physicians and 70 percent among cardiologists. Specificity was high (meaning a confident positive finding is usually real), but sensitivity was not 5 / Solid . This means that a “normal” cardiac examination in a patient with risk factors for valvular disease is not a reliable rule-out.

Echocardiography is the gold standard for murmur evaluation. When in doubt, order it. The cost of an echocardiogram is approximately $1,200 to $1,800 with professional and technical fees at most U.S. hospitals. The cost of missing moderate-to-severe MR that progresses to irreversible LV dysfunction is measured in years of quality life and eventual heart failure management.

Digital Auscultation and AI-Assisted Tools

Several commercial devices now offer digital stethoscopy with AI-assisted cardiac sound analysis. The Eko CORE digital stethoscope and the 3M Littmann Model 3200 record high-fidelity heart sounds that can be transmitted for specialist review. Eko’s AI algorithm, cleared by the FDA in 2022, detects moderate-to-severe left-sided valvular disease with sensitivity of 94.1 percent and specificity of 95.2 percent in validation studies 4 / Promising clearance data, DOI pending verification).

These tools do not replace echocardiography. They may narrow the population that needs urgent echocardiography versus routine evaluation, and they extend specialist-level auscultation to settings without specialist access. A rural primary care physician in Kankakee using an Eko device connected to a telemedicine cardiology program at Northwestern Medicine is providing better murmur care than the same physician relying on unaided auscultation alone.

This clinical framework integrates this layer explicitly: the Audit step includes systematic identification of patients with unreviewed echocardiograms, patients with prior murmur documentation without follow-up, and patients who have never had a formal cardiac auscultation recorded in the chart. These are not exotic clinical situations. They are daily occurrences in every practice above approximately 500 active patients.

Timing, Grading, and Documentation

A murmur that is accurately detected but poorly documented does not protect the patient who sees a different physician next year. The minimum documentation standard for a systolic murmur in a medical record is:

1. Grade (I through VI on the Levine scale)
2. Location (apex, LLSB, RUSB, LUSB)
3. Radiation (axilla, neck, back, none)
4. Quality (harsh, blowing, musical, vibratory)
5. Timing within systole (ejection, crescendo-decrescendo, or holosystolic)
6. Response to dynamic maneuvers if performed (Valsalva, squatting, standing)
7. Associated findings (clicks, S3, S4, abnormal S2)
8. Clinical impression with plan (echocardiogram ordered/pending/reviewed, or reason not ordered)

A chart note that says “2/6 systolic murmur” without location, quality, or plan is not a murmur evaluation. It is a placeholder that will be copied forward in every subsequent visit note without anyone taking action. This is how patients with moderate AS spend five years in a primary care practice without an echo, arrive with severe AS and HF, and are referred urgently to a structural heart program that could have intervened electively two years earlier.

The physical examination standard and the documentation standard are inseparable. Both are clinical skills. Both are taught inadequately in most residency programs. Both are within the scope of every physician who encounters a patient with a cardiac murmur, which is to say every physician in clinical practice.

The Signal Check is fifteen questions mapping the cardiovascular risk pattern across the physiological domains most commonly missed in standard screenings. It produces a specific starting point for your next clinical conversation.