51.2 Chronic Valvular Heart Disease & Murmur Evaluation

Bedside Physical Examination & Dynamic Auscultation Framework

Accurate bedside evaluation of cardiac murmurs remains one of the core clinical competencies in family medicine. Auscultation requires a systematic approach utilizing both the bell and diaphragm across the four classic anatomical cardiac landmarks:

1. Aortic Area: Second right intercostal space (RUSB) at the sternal border;
2. Pulmonic Area: Second left intercostal space (LUSB) at the sternal border;
3. Tricuspid Area: Fourth and fifth left intercostal spaces at the lower left sternal border (LLSB);
4. Mitral Area (Apex): Fifth left intercostal space at the midclavicular line.

Stethoscope Acoustic Principles: Bell vs. Diaphragm

• Diaphragm: Applied firmly against the skin to filter out low-frequency noise; optimal for high-pitched acoustic events: normal S1 and S2, systolic ejection murmurs (aortic stenosis), holosystolic murmurs (mitral and tricuspid regurgitation), early diastolic blowing murmurs (aortic regurgitation), and non-ejection systolic clicks.
• Bell: Applied lightly against the skin (firm pressure stretches the skin, turning it into a diaphragm that attenuates low frequencies); optimal for low-frequency acoustic vibrations: the S3 and S4 gallops and the low-pitched mid-diastolic rumble of mitral stenosis.

Dynamic Auscultation Maneuvers

Physiological and pharmacologic maneuvers alter cardiac loading conditions (preload, afterload, or heart rate) to differentiate overlapping murmurs.

                    HEMODYNAMIC EFFECTS OF DYNAMIC BEDSIDE MANEUVERS

   Maneuver                  Physiological Alteration             Murmur Response & Clinical Utility
   ═════════════════════════════════════════════════════════════════════════════════════════════════════════
   Inspiration               Increases venous return to right     Increases ALL right-sided murmurs
   (Carvallo Sign)           ventricle; decreases left return     (TR, TS, PR, PS); left-sided murmurs soften

   Expiration                Increases venous return to left      Increases ALL left-sided murmurs
                             atrium and ventricle                 (AS, MR, AR, MS); right-sided murmurs soften

   Standing / Valsalva       Decreases venous return (decreases   Softens MOST murmurs (AS, MR, AR);
   Strain (Phase II)         LV preload & end-diastolic volume)   EXCEPTIONS:
                                                                  • HOCM: Becomes LOUDER (increased obstruction)
                                                                  • MVP: Click & murmur move EARLIER; murmur lengthens

   Squatting / Passive       Increases venous return (increases   Intensifies MOST murmurs (AS, MR, AR);
   Leg Raise                 preload) & increases systemic afterload EXCEPTIONS:
                                                                  • HOCM: Becomes SOFTER (decreased obstruction)
                                                                  • MVP: Click & murmur move LATER; murmur shortens

   Sustained Handgrip        Increases systemic vascular          Intensifies REGURGITANT murmurs (MR, AR, VSD);
   (Isometric Exercise)      resistance (increases afterload)     Softens stenotic ejection murmurs (AS, HOCM)
   ═════════════════════════════════════════════════════════════════════════════════════════════════════════

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Systolic Murmurs: Aortic Stenosis (AS)

Aortic stenosis is the most prevalent valvular disease in developed nations, affecting 2% to 7% of adults older than 65 years.

Etiologies of Aortic Stenosis

1. Calcific Aortic Sclerosis / Degeneration: The predominant etiology in elderly adults (>70 to 75 years). Characterized by chronic endothelial injury, lipid accumulation, and active dystrophic calcification of an anatomically normal trileaflet aortic valve, sharing pathophysiological mechanisms with vascular atherosclerosis.
2. Congenital Bicuspid Aortic Valve: The most common congenital cardiac anomaly (occurring in 1% to 2% of the general population; male-to-female ratio 3:1). Abnormal shear stress across the asymmetric two-leaflet architecture accelerates calcific degeneration, causing severe stenosis to manifest two decades earlier than in trileaflet valves, typically presenting in adults aged 40 to 60 years. Strongly associated with thoracic aortic aneurysm, aortic dissection, and coarctation of the aorta.
3. Rheumatic Heart Disease: Prominent in developing countries; causes commissural fusion and leaflet thickening, almost universally accompanied by rheumatic mitral valve involvement.

Auscultatory Hallmarks

• The Murmur: A harsh, raspy, crescendo-decrescendo (diamond-shaped) systolic ejection murmur heard loudest at the right second intercostal space (RUSB). It radiates prominently upward into the bilateral carotid arteries (and suprasternal notch).
• The Gallavardin Phenomenon: In elderly patients with rigid, calcified aortic valves, the high-frequency acoustic components of the stenosis murmur are transmitted through the ventricular septum to the cardiac apex, where the murmur sounds high-pitched, musical, and blowing, easily masquerading as mitral regurgitation. It is distinguished from MR because it does not radiate to the axilla and retains its crescendo-decrescendo profile with beat-to-beat variation following premature ventricular contractions (post-PVC beat increases AS murmur intensity due to increased filling time, whereas MR remains constant).

Physical Examination Hallmarks of Severe AS

1. Pulsus Parvus et Tardus: The carotid arterial pulse exhibits diminished amplitude (parvus) and a delayed, slow-rising systolic peak (tardus), auscultated and palpated simultaneously with the cardiac apex.
2. Late-Peaking Murmur: In mild AS, the murmur peaks early in systole. As stenosis becomes severe, left ventricular ejection time is prolonged, causing the peak intensity to shift progressively toward late systole.
3. Diminished or Absent A2 (Aortic Closure Sound): Severe calcification immobilizes the aortic cusps, preventing crisp coaptation. A2 softens and eventually becomes inaudible.
4. Paradoxical (Reversed) Splitting of S2: Because LV ejection through the stenotic orifice is severely delayed, aortic valve closure (A2) occurs abnormally late, following pulmonic valve closure (P2) during expiration. On inspiration, P2 is normally delayed, merging with the delayed A2 into a single S2. On expiration, P2 occurs earlier, revealing a widely split S2.
5. S4 Gallop: Reflects vigorous atrial contraction into a non-compliant, concentrically hypertrophied left ventricle.

The Classic Symptom Triad & Natural History

Asymptomatic severe AS carries a low annual risk of sudden death (<1%). However, the onset of cardinal symptoms marks a catastrophic inflection point, after which survival plummets rapidly unless the valve is replaced:

• Angina (Average 5-Year Survival): Driven by severe LV hypertrophy, elevated LV wall tension, and compressed subendocardial capillaries, producing severe demand-supply myocardial ischemia even in the absence of epicardial CAD.
• Exertional Syncope (Average 3-Year Survival): During exertion, skeletal muscle vasodilation occurs normally, but cardiac output cannot increase across the fixed stenotic orifice, triggering acute cerebral hypoperfusion; also aggravated by exercise-induced activation of high-pressure LV baroreceptors triggering inappropriate systemic vasodilation and bradycardia (the Bezold-Jarisch reflex).
• Dyspnea / Heart Failure (Average 2-Year Survival): Reflects diastolic dysfunction with elevated LV filling pressures and pulmonary venous congestion, progressing to systolic decompensation.

                  DIAGNOSTIC ECHOCARDIOGRAPHIC CRITERIA FOR AORTIC STENOSIS

   Severity Category   Aortic Valve Area (AVA)    Mean Pressure Gradient    Peak Aortic Velocity (Vmax)
   ═════════════════════════════════════════════════════════════════════════════════════════════════════
   Aortic Sclerosis    > 2.0 cm2                  < 10 mmHg                 < 2.0 m/s (leaflet thickening)
   Mild AS             > 1.5 cm2                  < 20 mmHg                 2.0 to 2.9 m/s
   Moderate AS         1.0 to 1.5 cm2             20 to 39 mmHg             3.0 to 3.9 m/s
   Severe AS           <= 1.0 cm2                 >= 40 mmHg                >= 4.0 m/s
                       (Indexed <= 0.6 cm2/m2)
   Very Severe AS      <= 0.6 to 0.8 cm2          >= 60 mmHg                >= 5.0 m/s
   ═════════════════════════════════════════════════════════════════════════════════════════════════════

Definitive Management: TAVI vs. SAVR

Medical pharmacotherapy has no role in halting the progression of calcific AS (randomized trials confirm statins do not slow valve calcification). Vasodilators (nitrates, ACE inhibitors) must be used with extreme caution because afterload reduction in the presence of fixed outflow obstruction can precipitate profound hypotension and syncope.

• Indications for Valve Replacement:
  1. All symptomatic patients with severe AS (angina, syncope, heart failure, or reduced exercise tolerance);
  2. Asymptomatic severe AS with left ventricular systolic dysfunction (LVEF < 50%);
  3. Asymptomatic severe AS undergoing other cardiac surgery (e.g., CABG);
  4. Asymptomatic very severe AS (peak velocity >=5.0 m/s or mean gradient >=60 mmHg) or demonstrated exercise intolerance / fall in blood pressure on standardized exercise stress testing.
• Modalities:
  • Transcatheter Aortic Valve Implantation (TAVI / TAVR): Minimally invasive transfemoral catheter deployment; preferred in elderly patients (age >=75 to 80 years) or those with high/intermediate surgical risk.
  • Surgical Aortic Valve Replacement (SAVR): Mechanical or bioprosthetic open surgical replacement; preferred in younger patients (age <65 to 70 years), bicuspid anatomy with aortopathy, or patients requiring concurrent surgical revascularization.
• Surveillance of Asymptomatic Patients: Transthoracic echocardiography every 6 to 12 months for severe AS; every 1 to 2 years for moderate AS; every 3 to 5 years for mild AS.

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Systolic Murmurs: Mitral Regurgitation & Mitral Valve Prolapse

1. Chronic Mitral Regurgitation (MR)

• Primary (Organic) MR: Intrinsic structural disease of the mitral valve apparatus (leaflets, chordae tendineae, papillary muscles, or annulus). Prototypic causes: myxomatous degeneration / MVP, flail leaflet from spontaneous chordal rupture, and infective endocarditis.
• Secondary (Functional) MR: Leaflets and chordae are structurally normal; regurgitation is caused by left ventricular remodeling and geometric distortion. Ischemic cardiomyopathy (post-inferior MI with papillary muscle displacement) or dilated cardiomyopathy pulls the leaflets apart (apical tethering) and dilates the mitral annulus, preventing central coaptation.
• Auscultation:
  • A high-pitched, blowing holosystolic (pansystolic) murmur heard loudest at the cardiac apex.
  • Radiates characteristically to the left axilla (for anterior leaflet defects radiating posterolaterally; posterior leaflet defects can radiate anteriorly to the base).
  • The murmur intensity is constant throughout systole, obscures S1, and ends at S2.
  • S3 Gallop: Common in severe chronic MR, reflecting volume-overload rapid filling into an enlarged left ventricle.
  • Lateral and downward displacement of the hyperdynamic apical impulse.
• Definitive Management: Mitral valve surgical repair (preferred over replacement) is indicated for symptomatic severe chronic primary MR, or asymptomatic severe MR with LVEF <=60% or LV end-systolic diameter (LVESD) >=40 mm.

2. Mitral Valve Prolapse (MVP)

MVP affects 2% to 3% of the population and is characterized by myxomatous expansion of the spongiosa layer of the mitral valve leaflets with accumulation of glycosaminoglycans, causing the leaflets to billow superiorly into the left atrium during ventricular systole.

• Auscultation:
  • A crisp, high-pitched mid-systolic non-ejection click (produced by sudden tensing of elongated chordae tendineae and billowing leaflets as intraventricular pressure rises);
  • Followed by a late systolic crescendo murmur of mitral regurgitation heard at the apex.
• Dynamic Auscultation of MVP:
  • Maneuvers that DECREASE LV volume / preload (Standing, Valsalva strain Phase II): The smaller ventricular chamber causes the redundant leaflets to buckle and prolapse earlier in systole. Consequently, the click moves earlier (closer to S1) and the murmur becomes longer in duration.
  • Maneuvers that INCREASE LV volume / afterload (Squatting, Handgrip): The enlarged ventricular cavity keeps the leaflets aligned longer, delaying prolapse. Consequently, the click moves later (closer to S2) and the murmur becomes shorter and softer.

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Diastolic Murmurs: Aortic Regurgitation & Mitral Stenosis

[!CAUTION] THE CARDINAL RULE OF DIASTOLIC MURMURS Unlike systolic murmurs, which can frequently be functional or "innocent" (e.g., flow murmurs of pregnancy, anemia, fever, or youth), ALL DIASTOLIC MURMURS ARE PATHOLOGIC UNTIL PROVEN OTHERWISE.

Any patient with an audible diastolic murmur MANDATES A TRANSTHORACIC ECHOCARDIOGRAM for definitive structural and hemodynamic evaluation.

1. Chronic Aortic Regurgitation (AR)

• Etiologies:
  • Valvular Causes: Congenital bicuspid aortic valve, infective endocarditis, rheumatic heart disease.
  • Aortic Root Disease: Dilation of the aortic root and ascending aorta prevents leaflet coaptation: chronic systemic hypertension, ascending aortic aneurysm, Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome, syphilitic aortitis, and ankylosing spondylitis.
• Auscultation:
  • A high-pitched, blowing, early decrescendo diastolic murmur.
  • Heard best at the left third and fourth intercostal spaces (Erb's point) along the sternal border (when caused by primary valvular disease) or along the right sternal border (when caused by aortic root dilation).
  • Auscultatory Maneuver: Enhanced by having the patient sit upright, lean forward, and hold their breath in full expiration with the diaphragm firmly pressed to the chest wall.
  • The Austin Flint Murmur: A low-pitched, rumbling mid-to-late diastolic murmur heard at the cardiac apex. It is caused by the retrograde regurgitant jet striking the anterior leaflet of the mitral valve, causing partial closure and functional inflow turbulence across an anatomically normal mitral valve. Differentiated from mitral stenosis because there is no opening snap and no loud S1.
• Peripheral Hemodynamic Signs of Severe Chronic AR: Severe chronic AR produces a massive stroke volume ejected into the aorta followed by torrential diastolic run-off back into the left ventricle, resulting in an extreme wide pulse pressure (e.g., BP 165/45 mmHg):
  1. Corrigan (Water-Hammer) Pulse: Bounding, rapid arterial upstroke with sudden, precipitous diastolic collapse, felt prominently at the radial or brachial artery when elevated above the head.
  2. Quincke Sign: Rhythmic, alternating flushing and blanching of the nail bed capillaries visible upon applying gentle pressure to the tip of the fingernail.
  3. Traube Sign: Booming, loud, "pistol-shot" systolic sounds auscultated over the femoral arteries.
  4. Duroziez Sign: A systolic murmur heard over the femoral artery with gentle proximal compression, and a diastolic murmur heard with gentle distal compression.
  5. De Musset Sign: Rhythmic head bobbing synchronous with each cardiac cycle.
  6. Müller Sign: Systolic pulsation of the uvula.
  7. Hill Sign: Popliteal cuff systolic blood pressure exceeding brachial cuff systolic blood pressure by >20 mmHg (mild) or >60 mmHg (severe AR).
• Indications for SAVR: Symptomatic severe AR, or asymptomatic severe AR with LVEF <=55% or marked LV dilation (LV end-systolic diameter >50 mm).

2. Mitral Stenosis (MS)

• Etiology: Mitral stenosis is almost exclusively post-rheumatic in origin, resulting from acute rheumatic fever (ARF) caused by Group A beta-hemolytic streptococcal pharyngitis. A classic latent interval of 20 to 40 years separates the acute childhood infection from the onset of clinical symptoms.
• Pathology: Chronic post-inflammatory changes lead to fibrous thickening of leaflets, fusion of the commissures, and chordal shortening, creating a rigid, funnel-shaped "fish-mouth" orifice.
• Auscultation:
  1. Loud S1: High left atrial pressure holds the pliable leaflets wide open until the moment of ventricular contraction, slamming them shut forcefully.
  2. Opening Snap (OS): A sharp, high-pitched early diastolic sound following S2, produced by sudden deceleration and tensing of the fused mitral leaflets as they balloon into the LV under high left atrial pressure.
     • A2-OS Interval: The interval between aortic closure (A2) and the opening snap is inversely related to stenosis severity. A shorter A2-OS interval (<80 ms) reflects higher left atrial pressure snapping the valve open earlier in diastole, indicating more severe stenosis.
  3. Mid-Diastolic Rumbling Murmur: A low-pitched, rumbling diastolic murmur with presystolic accentuation (in patients maintaining sinus rhythm). Heard best with the bell of the stethoscope placed lightly at the apex with the patient in the left lateral decubitus position during expiration.
• Complications of Mitral Stenosis:
  • Severe Left Atrial Enlargement: High LA pressures cause massive atrial remodeling.
  • Atrial Fibrillation: Develops in >40% to 50% of patients. Loss of the atrial "kick" combined with rapid ventricular rates precipitates sudden hemodynamic collapse and pulmonary edema.
  • Systemic Thromboembolism: Sluggish flow in the giant left atrium and left atrial appendage creates a high risk of mural thrombus and stroke. All patients with MS and atrial fibrillation mandate anticoagulation, irrespective of their CHA2DS2-VASc score.
  • Pulmonary Hypertension & Hemoptysis: High retrograde pulmonary venous pressures induce reactive pulmonary arterial vasoconstriction. Rupture of engorged bronchial-pulmonary venous anastomoses causes massive hemoptysis ("pulmonary apoplexy").
  • Ortner Syndrome (Cardiovocal Syndrome): Hoarseness caused by compression of the left recurrent laryngeal nerve between a massively dilated left atrium and the aorta.
• Definitive Management: Percutaneous Mitral Balloon Commissurotomy (PMBC) is the procedure of choice for symptomatic severe MS (mitral valve area <=1.5 cm2) if leaflet morphology is favorable (Wilkins score <=8; pliable leaflets without extensive subvalvular calcification, absence of left atrial thrombus, and absence of significant mitral regurgitation). Surgical replacement is indicated if PMBC criteria are not met.

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2021 AHA/ACC Infective Endocarditis Prophylaxis Guidelines

Historically, antibiotic prophylaxis was broadly administered to patients with a wide variety of native cardiac conditions. However, clinical trials and large epidemiological cohorts demonstrated that transient bacteremias resulting from routine daily activities (tooth brushing, flossing, chewing food) occur thousands of times per year and represent the overwhelming source of infective endocarditis (IE), whereas antibiotic prophylaxis prior to dental procedures prevents only an exceedingly small fraction of IE cases.

The Four High-Risk Cardiac Categories Qualifying for Prophylaxis

Under current 2021 AHA/ACC guidelines, antibiotic prophylaxis prior to high-risk dental procedures is STRICTLY RESTRICTED to patients with the highest risk of adverse outcomes or mortality from infective endocarditis:

1. Prosthetic Heart Valves or Prosthetic Material: Includes mechanical and bioprosthetic valves, transcatheter-implanted valves (TAVI), and prosthetic rings or annuloplasty bands used for valve repair;
2. Previous History of Infective Endocarditis (confers an exceptionally high recurrence and destruction rate);
3. Congenital Heart Disease (CHD):
   • Unrepaired cyanotic CHD, including palliative shunts and conduits;
   • Completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or transcatheter intervention, during the first 6 months following the procedure (allowing time for endothelialization);
   • Repaired CHD with residual defects at or adjacent to the site of a prosthetic patch or prosthetic device (which inhibits full endothelialization);
4. Cardiac Transplant Recipients who develop cardiac valvulopathy.

                  SUMMARY: WHO GETS INFECTIVE ENDOCARDITIS PROPHYLAXIS?

   PROPHYLAXIS INDICATED (High-Risk Conditions)       PROPHYLAXIS NO LONGER INDICATED (Native Conditions)
   ═══════════════════════════════════════════════════════════════════════════════════════════════════════
   • Prosthetic cardiac valves (mechanical/bioprosthetic) • Native bicuspid aortic valve (without prior IE)
   • Prosthetic rings / bands / clips for valve repair  • Calcific aortic stenosis / sclerosis
   • PREVIOUS EPISODE OF INFECTIVE ENDOCARDITIS         • Mitral valve prolapse (with or without MR)
   • Unrepaired cyanotic congenital heart disease       • Rheumatic heart disease
   • Completely repaired CHD with prosthetic < 6 months  • Hypertrophic cardiomyopathy (HOCM)
   • Repaired CHD with residual defect near patch       • Ventricular or atrial septal defects (repaired >6m)
   • Cardiac transplant recipient with valvulopathy     • Routine GI / GU procedures (Colonoscopy, EGD, Cysto)
   ═══════════════════════════════════════════════════════════════════════════════════════════════════════

Qualifying Procedures

• Dental Procedures: Indicated ONLY for dental procedures that involve manipulation of gingival tissue, the periapical region of teeth, or perforation of the oral mucosa (e.g., dental extractions, periodontal surgery, subgingival scaling, root canal instrumentation).
• Non-Qualifying Procedures: Routine local anesthetic injections through non-infected tissue, taking dental radiographs, placement of removable appliances, shedding of deciduous teeth, or bleeding from trauma to the lips/oral mucosa.
• GI and GU Procedures: Antibiotic prophylaxis is NO LONGER RECOMMENDED for routine gastrointestinal or genitourinary procedures (including upper endoscopy [EGD], colonoscopy, sigmoidoscopy, cystoscopy, or transurethral resection), even in patients with prosthetic heart valves.

Guideline-Directed Antibiotic Regimens

Administered as a single oral dose 30 to 60 minutes prior to the procedure:

• First-Line Standard: Oral Amoxicillin 2 g (pediatric dosing: 50 mg/kg up to 2 g max).
• Unable to Take Oral Medication: Intravenous or intramuscular Ampicillin 2 g OR Cefazolin/Ceftriaxone 1 g.
• Allergic to Penicillins / Ampicillin:
  • Oral Cephalexin 2 g (pediatric: 50 mg/kg up to 2 g; provided there is no history of anaphylaxis, angioedema, or hives to penicillins);
  • Oral Azithromycin or Clarithromycin 500 mg (pediatric: 15 mg/kg up to 500 mg);
  • Oral Doxycycline 100 mg (pediatric: 2.2 mg/kg up to 100 mg).

[!CAUTION] CLINDAMYCIN IS NO LONGER RECOMMENDED FOR IE PROPHYLAXIS The AHA/ACC guidelines explicitly removed Clindamycin from the recommended IE prophylaxis regimens. Clindamycin administration was found to cause a disproportionate incidence of severe, fatal Clostridioides difficile colitis, while offering unreliable bactericidal efficacy against viridans group streptococci.