Mitral Valve Quiz

Valvular Heart Disease Overview

• The presentation covers valvular heart disease, focusing on mitral valve stenosis and regurgitation.
• Mitral stenosis is the narrowing of the mitral valve, hindering blood flow.
• Mitral regurgitation involves blood leaking backward through the mitral valve during the heart's pumping cycle.
• Mitral valve lesions, stenosis and regurgitation, worsen with increasing severity, leading to various symptoms.
• Acute mitral regurgitation or stenosis requires rapid diagnosis and treatment.

Intended Learning Objectives

• The objectives cover essential aspects of valvular diseases, including:
  • Understanding common causes.
  • Recognizing signs, symptoms.
  • Diagnosing and treating acute regurgitation/stenosis.
  • Identifying patients for surgical valve replacement and post-procedure follow-up.

Overview

• The presentation highlights mitral stenosis, mitral regurgitation, and distinctions between acute and chronic forms.

Etiology of Mitral Stenosis

• The most common cause of mitral stenosis is rheumatic heart disease (77-99%).
• Other etiologies include infective endocarditis (3.3%) and mitral annular calcification (2.7%).

Mitral Valve Anatomy

• A labeled diagram presents the key anatomical components of the mitral valve.

Mitral Stenosis Overview

• Mitral stenosis obstructs blood flow from the left ventricle (LV) to the left atrium (LA) during diastole.
• Normal mitral valve area ranges from 4-6 cm².
• Symptoms emerge when the mitral valve area narrows below 2 cm².

Mitral Regurgitation Pathophysiology (MR)

• Chronic mitral regurgitation (MR) results in blood flowing backward from the left ventricle to the left atrium during systole.
• Mild mitral regurgitation is common (present in 80% of normal individuals)

Etiology of Acute MR

• Acute mitral regurgitation can stem from infective endocarditis.
• Acute myocardial infarction can trigger acute mitral regurgitation.
• Malfunction of a prosthetic valve is another potential cause.

Management of Acute MR

• Beta-blockers are not usually useful for managing tachycardia in acute MR.
• Diuretics and vasodilators such as nitroprusside are often used for acutely ill patients with heart failure related to severe mitral regurgitation
• Surgical treatment (balloon pump or emergent surgery) often becomes necessary for severe acute cases.

Mitral Regurgitation Pathophysiology

• Pure volume overload is a key characteristic as blood backs up from the left ventricle.
• Compensatory processes like left atrial and left ventricular hypertrophy initially help the heart cope.
• Progressive left ventricular dilation and right ventricular dysfunction from pulmonary hypertension eventually occur.

Physical Examination Findings in MR

• A soft S1 and a holosystolic murmur radiating to the axilla are common findings.
• An S3 (CHF/LA overload) might be present, and the murmur intensity often correlates with severity.
• Exertion dyspnea (exercise intolerance) and signs of heart failure (e.g., pregnancy, infection or atrial fibrillation) are frequently seen.

Natural History of MR

• Patients often have a compensatory phase of 10 -15 years.
• 5%/year mortality can occur if the effective ejection fraction (EF) drops below 60%.
• Mortality increases sharply once symptoms develop.

Imaging Studies for MR

• ECG may show left atrial (LA) enlargement.
• CXR can reveal LA enlargement or central pulmonary artery enlargement.
• Echocardiography (ECHO) is crucial to evaluate mitral valve structure, assessing left atrium (LA), left ventricle (LV) size, and function.
• Transesophageal echocardiography (TEE) is sometimes used if transthoracic ECHO is inconclusive.

Grading of MR Severity

• A table outlines the qualitative and quantitative methods for grading the severity of mitral regurgitation, considering various metrics (e.g., vena contracta width).

Management of MR (Medications)

• Vasodilators (e.g., hydralazine)
• Rate control for atrial fibrillation using beta-blockers, calcium channel blockers or digoxin
• Anticoagulation (especially for atrial fibrillation or flutter).
• Diuretics to manage fluid overload.

Management of MR (Prophylaxis)

• IE prophylaxis is critical for patients with prosthetic heart valves or a history of infective endocarditis (IE).
• It is important to ensure timely prophylactic intervention, especially for high-risk patients likely to need procedures requiring oral/dental hygiene or procedures involving mucous membranes.

Simplified Indications for MV Replacement

• Any symptomatic patient with NYHA Class III or IV symptoms.
• Asymptomatic individuals with moderate or severe MS that isn't suitable for percutaneous balloon valvotomy, or significant EF <60% and/or new onset atrial fibrillation.

Pretest Questions

• Students are asked to prepare before the lecture, considering mitral valve functions, location, diseases, and management strategies.