B.35 Mitral Valve Regurgitation Flashcards
B.35 Mitral Valve Regurgitation
Is the leakage of blood from the left ventricle into the left atrium due to incomplete closure of the mitral valve during systole. It is a common form of valvular disease and categorized according to onset (into acute and chronic forms) and etiology.
B.35 Mitral Valve Regurgitation
Primary etiology
Primary MR (Organic)
Mitral Regurgitation (MR) resulting from direct involvement of the valve leaflets or chordae tendineae includes:
- Degenerative mitral valve disease: Such as mitral valve prolapse, mitral annular calcification, and ruptured chordae tendineae.
- Rheumatic fever
- Infective endocarditis
- Ischemic MR: For example, due to apical muscle rupture following an acute myocardial infarction (MI).
B.35 Mitral Valve Regurgitation
Secondary Etiology
Mitral Regurgitation (MR) that arises from changes in the left ventricle leading to valve incompetence includes:
- Coronary Artery Disease (CAD) or previous myocardial infarction (MI) affecting papillary muscle function.
- Dilated cardiomyopathy: For example, peripartum cardiomyopathy and left heart failure (LHF).
B.35 Mitral Valve Regurgitation
Acute MR
Acute MR
Acute dysfunction of the mitral valve leads to volume overload and symptoms of acute heart failure.
B.35 Mitral Valve Regurgitation
Chronic MR
- To maintain cardiac output, valve dysfunction is initially compensated by cardiac remodeling.
- Over time, this remodeling impacts left ventricular ejection fraction, ultimately leading to heart failure.
B.35 Mitral Valve Regurgitation
Acute mitral regurgitation pathophys
Acute MR: Increased left atrial end-diastolic volume (EDV) leads to rapid elevation in left atrial and pulmonary pressure, resulting in pulmonary venous congestion and pulmonary edema.
B.35 Mitral Valve Regurgitation
Acute MR Clinical
Signs and Symptoms:
- Dyspnea
- Symptoms of left heart failure (LHF)
- Signs and symptoms of pulmonary edema (e.g., bibasilar crackles, fine late inspiratory crackles)
- Cardiogenic shock: characterized by poor peripheral perfusion, tachycardia, tachypnea, and hypotension
- Palpitations
Diagnostics:
B.35 Mitral Valve Regurgitation
Acute MR Auscultation
Auscultation
- Soft, decrescendo murmur
- Absence of murmur in severe regurgitation with left ventricular (LV) dysfunction or hypotension
- Possible presence of S3 heart sound
further imaging and treatment options are determined by the etiology.
B.35 Mitral Valve Regurgitation
Acute MR DX
Echocardiography
- Indications: Used to evaluate the valve apparatus, assess left ventricular size and function, and determine the severity of mitral regurgitation (MR).
- TTE: Preferred method for the initial evaluation of all patients suspected of having MR.
- Note: Conducted before surgery and during the diagnostic assessment if transesophageal echocardiography (TEE) is insufficient.
Laboratory Studies
- Troponin: Elevated levels may indicate myocardial ischemia.
- BNP: NORMAL Usually associated with acute onset of symptoms.
B.35 Mitral Valve Regurgitation
Acute MR ECG
Findings are frequently nonspecific, including:
- Normal sinus rhythm
- Sinus tachycardia with nonspecific ST and T-wave changes
- Atrial fibrillation
- Signs of acute ischemia in cases of ischemic MR
B.35 Mitral Valve Regurgitation
Acute MR Medical TX
Heart Failure Management:
Vasodilators: Used to decrease afterload and improve cardiac output.
Nitroprusside: A potent vasodilator.
Nitrates: For additional support (e.g., nitroglycerin).
Diuretics: To address pulmonary edema (e.g., furosemide).
Atrial Fibrillation: Consider cardiac re-synchronization therapy to enhance hemodynamics.
Heart Bridging Devices: For patients with worsening symptoms who are not candidates for immediate surgery.
B.35 Mitral Valve Regurgitation
Acute MR Surgical TX
- Patients with acute primary MR must undergo urgent surgical intervention.
- While waiting for surgery, symptoms of heart failure should be managed with medical therapy.
Surgical Therapy
- Indications:
- Acute primary MR (urgent surgery) or acute secondary MR that does not respond to medical treatment.
B.35 Mitral Valve Regurgitation
Chronic MR Pathophys
Chronic (Compensated) MR:
- The left ventricle (LV) undergoes dilation due to eccentric hypertrophy, leading to an increase in volume capacity (both preload and afterload return to normal). This results in an increased end-diastolic volume (EDV), which helps maintain stroke volume and normal ejection fraction (EF).
Chronic (Decompensated) MR:
- Progressive enlargement of the LV and myocardial dysfunction cause a decrease in stroke volume. This results in increased end-systolic volume (ESV) and end-diastolic volume (EDV), alongside elevated left ventricular (LV) and left atrial (LA) pressures. Consequently, pulmonary congestion may occur, potentially leading to acute pulmonary edema, pulmonary hypertension, and right heart strain.
B.35 Mitral Valve Regurgitation
Chronic MR Clinical
Signs and Symptoms:
- Dyspnea: Includes exertional dyspnea and dry cough.
- Fatigue
- Palpitations
- Symptoms of Left Heart Failure (LHF): May also include symptoms of Right Heart Failure (RHF).
B.35 Mitral Valve Regurgitation
Chronic MR Ausculatation
Quiet S1 Heart Sound
- S3 Heart Sound: Present in advanced stages of the disease.
- S4 Heart Sound: May be observed in functional mitral regurgitation.
- Holosystolic, High-Pitched “Blowing Murmur”: Loudest at the apex and radiates toward the axilla.
- Intensity Changes:
- Increased with preload (e.g., passive leg raise and squatting).
- Increased with afterload (e.g., handgrip).
- Increased with preload (e.g., Valsalva maneuver) and venous return (inspiration).
B.35 Mitral Valve Regurgitation
Chronic MR DX
TTE (Transthoracic Echocardiography): Used to confirm diagnosis and classify patients with suspected mitral regurgitation. Always check ECG and troponin levels in acute MR to evaluate myocardial injury. Consider additional diagnostics (e.g., coronary angiography, blood cultures) based on symptoms and underlying condition.
Echocardiography:
Indications: Assess the valve structure, size, and function of the left ventricle and atrium, as well as determine the severity of MR.
- TTE: Recommended as the first choice for all patients with suspected valvular disease.
- TEE (Transesophageal Echocardiography): Suggested prior to surgery if TTE results are inadequate.
Laboratory Studies:
- Troponin Levels: Elevation may indicate myocardial ischemia.
BNP (B-type Natriuretic Peptide):
- Chronic MR: Usually elevated as the severity of regurgitation increases and the left ventricle is affected.
Note:
Myocardial ischemia must be ruled out in patients presenting with mitral regurgitation!
B.35 Mitral Valve Regurgitation
Chronic MR ECG
ECG changes typically indicate cardiac remodeling:
- Left Ventricular Hypertrophy (LVH): Present in 50% of patients.
- P Mitrale: Indicative of atrial enlargement.
- Atrial Fibrillation: Commonly observed.
- Signs of Right Heart Strain: May appear in later stages, alongside P Pulmonale.
B.35 Mitral Valve Regurgitation
Chronic MR CXR
- Chronic Mitral Regurgitation (MR): Changes due to cardiac remodeling and associated heart failure can include visible LV enlargement, LA enlargement, and annular calcification.
Additional Evaluation:
- Cardiac MRI (CMR): Useful if TTE and TEE findings are inconclusive, particularly for suspected cardiomyopathy or ischemic heart disease.
- Stress Echo: Employed in cases of ischemic MR to evaluate the necessity for surgical intervention.
- Coronary Angiography: Recommended in suspected ischemic heart disease before proceeding with surgical treatment.
B.35 Mitral Valve Regurgitation
Chronic MR Medical TX
Identify and Address Underlying Causes: Focus on treating any specific factors, especially in cases of secondary mitral regurgitation (MR).
Heart Failure Management:
- Diuretics (e.g., furosemide)
- ACE Inhibitors (e.g., lisinopril)
- Beta Blockers (e.g., metoprolol tartrate)
B.35 Mitral Valve Regurgitation
Chronic MR Surgical TX
Surgical Management and Transcatheter Mitral Repair
- Indications:
- Asymptomatic Patients: With left ventricular (LV) dysfunction (LVEF 30–60% or LV end-systolic diameter ≥ 40 mm)
- Symptomatic Patients: With LVEF between 30–60%
- Contraindications: If LVEF is < 30%, surgery is generally not recommended due to high mortality risk and low likelihood of symptom improvement.
Chronic Secondary Mitral Regurgitation (MR)
- Indications: Consider for patients with severe MR and persistent symptomatic heart failure (NYHA class III-V) despite optimal medical management.
B.35 Mitral Valve Regurgitation
Intra-aortic balloon pump
A circulatory assist device placed in the descending aorta to increase myocardial perfusion. Consists of a double-lumen catheter with an attached balloon close to the tip. Hemodynamic monitoring is used to time inflation and deflation of the balloon. Inflation during diastole leads to increased blood flow into the coronary arteries, while deflation during systole reduces afterload. Typically used as a bridge therapy in conditions with acutely reduced cardiac output (e.g., cardiogenic shock and refractory heart failure).
