Mitral Regurgitation Overview

Mitral Regurgitation (MR)

• Signs and Symptoms:
  • Distended neck veins
  • Hyperdynamic and displaced apex beat
  • Apical systolic thrill
  • Soft S1
  • Widely split S2, accentuated with pulmonary hypertension
  • S3 at apex
  • Soft blowing pan-systolic murmur at apex radiating to axilla
  • Diastolic flow murmur over apex (functional mitral stenosis)
• Investigations:
  • ECG: shows left ventricular and left atrial enlargement
  • Chest X-ray: shows cardiac enlargement and pulmonary vascular congestion
  • Echocardiography: Confirms diagnosis, determines cause (e.g., MVP), severity of MR, regurgitant fraction, heart chamber sizes, and pulmonary pressure
• Treatment:
  • Medical Therapy:
    • No evidence to support prophylactic use of vasodilators in chronic MR with normal EF
    • BP control in hypertension
    • Loop diuretics for exertional or nocturnal dyspnea
  • Surgical Therapy:
    • Repair preferred to replacement
    • Indications: Limiting symptoms despite medical management, LV failure, LV dilatation, other planned open-heart surgeries

Mitral Valve Prolapse (MVP)

• Common congenital valvular abnormality (2-3% of population)
• More common in young women
• Mostly asymptomatic
• Symptoms: Dizziness, palpitations, syncope, chest pain
• Auscultation: Mid-to-late systolic click and late systolic murmur at the cardiac apex
  • Worsens with Valsalva maneuver or standing
  • Improves with squatting or leg raise
• Complications: Serious arrhythmias, CHF, acute MR, risk of infective endocarditis
• Treatment: Beta blockers for chest pain and palpitations, mitral valve repair/replacement in some cases

Aortic Stenosis (AS)

• Causes:
  • Calcific: Senile calcification of trileaflet valve (most common)
  • Congenital: Calcification of congenitally bicuspid aortic valve
  • Rheumatic: Aortic valve affected by rheumatic fever, mitral valve also usually affected
• Pathogenesis:
  • AS leads to increased left ventricular systolic pressure, resulting in left ventricular hypertrophy to maintain cardiac output without dilatation
  • Further increase in left ventricular diastolic pressure leads to forceful left atrial contraction to aid ventricular filling
  • This can cause symptoms of pulmonary venous congestion
  • Decreased cardiac output and forward flow can cause exertional syncope
  • Left ventricular hypertrophy and high intramyocardial wall tension increase oxygen demand and decrease coronary blood flow, potentially causing myocardial ischemia and angina
• Symptoms: (Usually exertional, classic triad)
  • Angina pectoris
  • Syncopal attacks
  • Dyspnea and orthopnea from CHF
• Life Expectancy: <5 years once symptomatic
• Examination:
  • General: Pulsus tardus and parvus, carotid thrill
  • Local:
    • Inspection and Palpation: Heaving sustained apex, not shifted, palpable thrill at A1 area (right second intercostal space)
    • Auscultation: Muffled S2, S4, aortic ejection click (bicuspid valve), harsh ejection crescendo-decrescendo systolic murmur, maximum intensity at A1, radiates to carotids
• Clinical Indicators of Severity: Abnormal pulse, heaving sustained apex, decreased S2, longer duration of murmur with late peaking
• Differential Diagnosis: Aortic valve sclerosis in the elderly, functional AS murmur (occurring with aortic regurgitation), hypertrophic obstructive cardiomyopathy (HOCM), mitral regurgitation
• Treatment:
  • Medical Therapy:
    • Management of symptoms
    • Medications may assist in symptom control
  • Surgical Therapy: Aortic valve replacement, minimally invasive surgical techniques may be considered

Infective Endocarditis

• Causes: Bacterial infection of heart valves
• Classification:
  • Acute Infective Endocarditis:
    • Caused by virulent bacteremia, resulting in large vegetations
    • Staph. aureus is the most common organism
    • Rapid onset with fever, sepsis
    • IV drug use a major risk factor (often tricuspid valve)
    • Associated with myocardial abscesses and rapid valve destruction
    • Embolic complications, especially pulmonary abscesses with right-sided lesions
    • Treatment: Intensive antibiotics and often surgery
  • Subacute Infective Endocarditis:
    • Less fatal than acute endocarditis
    • Associated with low virulence
    • Commonly caused by viridans group streptococci
    • Smaller vegetations
    • Slow onset with vague symptoms, including malaise, low-grade fever, weight loss, flu-like symptoms
    • Risk factors: Preexisting valve abnormalities, congenital heart disease, prosthetic valves
    • Valve destruction can occur and may require surgery
• Microorganisms:
  • Native Valve Endocarditis: Streptococcus viridans (most common), staphylococcus aureus, other streptococci
  • IV Drug Users: Staphylococcal infections
  • Early Prosthetic Valve Endocarditis: Staphylococcus epidermidis
  • Late Prosthetic Valve Endocarditis: Similar to native valves, streptococcus viridans
• Complications: CHF (most common cause of death), septic embolization (brain, spleen, kidneys, coronary arteries), vasculitis, glomerulonephritis, cardiac abscess
• Clinical Manifestations:
  • Symptoms: Fever, chills, sweating, fatigue, weight loss, dyspnea, anorexia, cough
  • Physical Signs: Fever, clubbing, signs of vasculitis or embolic events, splenomegaly, glomerulonephritis, mycotic aneurysms, heart murmur (new or changing)
  • Peripheral Signs: Petechiae, splinter hemorrhages, Osler's nodes, Janeway lesions, Roth's spots
• Treatment:
  • Requires antibiotics for treatment
  • Surgery may be needed in certain cases

Hypertension

• Definition: Sustained elevation of blood pressure
• Risk Factors: Age, family history, race, obesity, smoking, excessive sodium intake, lack of physical activity, stress, excessive alcohol consumption, certain medical conditions (e.g., diabetes, kidney disease)
• Complications: Heart disease, stroke, kidney disease, eye damage, peripheral vascular disease
• Measurement and Classification:
  • Measured using a sphygmomanometer
  • Classification based on systolic and diastolic blood pressure readings
• Treatment:
  • Lifestyle modifications (e.g., weight loss, diet, exercise, smoking cessation)
  • Medications (e.g., diuretics, beta-blockers, ACE inhibitors, calcium channel blockers, angiotensin receptor blockers)
• Assessment:
  • Symptoms: Headache, dizziness, nosebleeds, blurred vision, chest pain, shortness of breath
  • Physical Examination:
    • Check blood pressure
    • Assess for signs of target organ damage (e.g., retinal changes, heart murmurs, enlarged heart)
• Investigations:
  • Urine and blood tests (e.g., creatinine, electrolytes, glucose)
  • ECG
  • Chest X-ray
  • Echocardiogram

Atrial Fibrillation (AF)

• Definition: Irregular, rapid heart rhythm originating from the atria
• Causes:
  • Age
  • Hypertension
  • CAD
  • Valvular heart disease
  • Congestive heart failure
  • Underlying heart conditions
  • Hyperthyroidism
  • Alcohol abuse
  • Hypoxia
• Symptoms:
  • Palpitations
  • Fatigue
  • Shortness of breath
  • Dizziness
  • Chest pain
• Physical Examination: Irregular pulse, rapid heart rate, may have signs of underlying cardiac conditions
• Investigations:
  • ECG: Confirms AF rhythm, identifies other abnormalities like left ventricular hypertrophy, pre-excitation, prior MI
  • Chest X-ray: Detects lung disease
  • Transthoracic Echocardiogram: Detects LVH, valvular disease, atrial size
  • Transesophageal echo: To rule out left atrial thrombus before cardioversion
  • Thyroid function and electrolyte tests: Exclude hyperthyroidism and electrolyte abnormalities
• Classification and Patterns:
  • Paroxysmal: Episode resolves within 7 days (usually < 24 hours)
  • Persistent: Episode lasts > 7 days
  • Long-standing persistent: Episode sustained > 1 year, with decision for rhythm control strategy
  • Permanent: AF lasting more than a year, with decision to stop attempts to restore sinus rhythm and accept AF as permanent
• Treatment:
  • Ventricular Rate Control:
    • Often considered for minimal symptoms
    • Target heart rate is < 100 beats/min
  • Rhythm Control:
    • Attempts to restore and maintain normal sinus rhythm
  • Anticoagulation:
    • Prevent embolic complications (stroke)
• Medications:
  • Rate control medications:
    • Beta blockers
    • Calcium channel blockers
    • Digoxin
  • Rhythm control medications:
    • Antiarrhythmic drugs
    • Electrocardioversion (may be needed)
• Procedures:
  • Catheter ablation: May be used to destroy the areas of the heart responsible for AF
  • Pacemaker: May be used to control heart rhythm
• Prognosis:
  • AF can increase the risk of stroke, heart failure, and other complications
  • Treatment and lifestyle modifications can improve long-term health outcomes

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