Mitral Regurgitation

IM

Mitral Regurgitation

Chronic Mitral Regurgitation Overview

Definition: Backflow of blood from the LV to the LA during systole

Mild (physiological)
MR is seen in 80% of normal individuals.

Pathophysiology

Acute MR: ↑ LV end-diastolic volume → rapid ↑ LA and pulmonary pressure → pulmonary venous congestion → pulmonary edema

Chronic (compensated) MR: progressive dilation of the LV (via eccentric hypertrophy) → ↑ volume capacity of the LV (preload and afterload return to normal values) → ↑ end-diastolic volume → maintains ↑ stroke volume (normal EF)

Chronic (decompensated) MR: progressive LV enlargement and myocardial dysfunction → ↓ stroke volume → ↑ end-systolic and end-diastolic volume → ↑ LV and LA pressure → pulmonary congestion, possible acute pulmonary edema, pulmonary hypertension, and right heart strain

Acute MR

• Endocarditis

• Acute MI: papillary muscle infarction ruptured chordae tendineae

• Malfunction or disruption of prosthetic valve

• Acute rheumatic fever

Etiologies of Chronic Mitral Regurgitation

• Myxomatous degeneration (MVP)

• Ischemic MR

• Rheumatic heart disease

• Infective Endocarditis

• Connective tissue disease (Ehlers–Danlos syndrome, Marfan’s syndrome)

• Coronary heart disease: ischemic mitral regurgitation

• Left ventricular dilatation: cardiomyopathy.

Mitral valve prolapse

Clinical features

Key features

Acute mitral regurgitation

• Emergency: Sudden onset severe dyspnea & rapidly progressive pulmonary edema

• Hypotension and cardiogenic shock

Chronic mitral regurgitation

• Asymptomatic if mild or moderate

• Symptoms: when left HF develops (severe MR dyspnea on exertion

• Fatigue

• Atrial fibrillation

• At risk of developing infective endocarditis

Physical Exam findings in MR

• Exertion Dyspnea: (Exercise intolerance)

• Auscultation: Soft S1 and a holosystolic murmur at the apex radiating to the axilla

• S3 (CHF/LA overload)

• In chronic MR, the intensity of the murmur does correlate with the severity.

• Heart Failure: coincide with increased hemodynamic burden e.g., pregnancy, infection or atrial fibrillation

Investigations

Echocardiography and Doppler
ALL patients: Trans-thoracic echocardiography with Doppler; determine left and right ventricular function and pulmonary artery pressures

ECG

• AF common
• P-mitrale (bifid P waves) due to left atrial enlargement
• Changes uncommon in acute mitral regurgitation

CXR

• Cardiomegaly: enlarged left atrium and ventricle

• Signs of congestive heart failure

• Acute MR: heart size is usually normal but shows pulmonary edema (alveolar edema).

Treatment

Acute mitral regurgitation

• All patients: primary urgent surgical repair or valve replacement.

• Manage HF before surgery. (diuretics, nitrates, antihypertensive drugs).

• If secondary MR: identify and treat the underlying cause (revascularization therapy for ischemic MR)

Surgical therapy:
Indications

• Acute primary MR (urgent surgery)
• Acute secondary MR that does not adequately respond to medical therapy

Procedures

• Valve repair: preferred option because of the reduced risk of mortality and complications
• Valve replacement: severe destruction of the mitral valve
• Revascularization therapy: ischemic MR with papillary muscle rupture`

Medical therapy

• Temporizing measure before surgery

• Vasodilators: to reduce afterload and improve cardiac output e.g. Nitroprusside, Nitrates

• Diuretics: furosemide: acute pulmonary edema

• Hypotension: inotropes (dobutamine)

• Atrial fibrillation: cardiac resynchronization therapy to improve hemodynamics.

Chronic mitral regurgitation

Medical therapy: all patients to optimize cardiac function but surgery is the definitive treatment option.

Medical management:

• Identify & treat underlying cause 2nd MR

• Heart failure

  • Diuretics: furosemide

  • ACE inhibitors: Lisinopril

  • Beta blockers: Metoprolol

• Ischemic MR: revascularization therapy

• Atrial fibrillation: evaluation for cardiac resynchronization therapy

Surgical

• LV dysfunction: LVEF 30–60%
• Severe MR and persistent symptomatic heart

Management of chronic MR: symptoms and extent of heart failure and the cause of MR because of the high mortality rate and low likelihood of symptom improvement.

• Left ventricular assisted device

Complications

• Heart failure; pulmonary edema
• Cardiogenic shock
• Atrial fibrillation
  • Increases risk of stroke and other thromboembolic complications
• Acute decompensation of heart failure in chronic MR
• Endocarditis
• Pulmonary artery hypertension

Case 1

A 20-year-old man is evaluated for sudden onset palpitations, dyspnea, and dizziness. His temperature is 36.0°C, pulse is 102/min, and blood pressure is 135/86 mmHg. Chest examination demonstrates pectus excavatum. Cardiac auscultation reveals a mid systolic click followed by a late-systolic crescendo murmur over the cardiac apex. ECG demonstrates. Which of the following is the most likely diagnosis?

• Coarctation of the aorta

• Aortic stenosis

• Mitral valve prolapse

• Mitral stenosis

• Ventricular septal defect

Case 2

A 70-year-old woman is being evaluated for sudden onset dyspnea. 3 days prior, she underwent PCI, which demonstrated right coronary artery stenosis. The ECG at that time demonstrated ST-segment elevation in leads II, III, and aVF. Current temperature is 37.0°C, pulse is 120/min, respirations are 20/min, and blood pressure is 90/50 mmHg. On physical examination, the following murmur pattern is appreciated over the 5th left midclavicular intercostal space. Which of the following is the most likely explanation for this patient’s new onset dyspnea?

• Ventricular septal rupture

• Ventricular aneurysm

• Papillary muscle rupture

• Ventricular arrhythmia

• Left ventricular free wall rupture

Mitral + tricuspid Regurge, VSD,

Tricuspid increased with inspiration, on tricuspid area or left sternal border

VSD in 3rd ICS - can be found in any area of the chest