Lecture Notes on Mitral Valve Stenosis

Overview

• Mitral valve stenosis often occurs 20 years after rheumatic heart disease
• Commonly seen in third world countries, particularly in the tropics
• Typically affects 30-year-old patients due to earlier rheumatic heart disease in childhood

Symptoms

• Dyspnea: Shortness of breath
• Orthopnea: Shortness of breath when lying down
• Paroxysmal Nocturnal Dyspnea: Sudden shortness of breath at night
• Possible hemoptysis due to back pressure in the left atrium
• Atrial fibrillation: Dilated left atrium may cause this
• Thrombus formation: Possible due to enlarged atrium
• Jet lesions: Can occur in the left ventricle
• Bronchus obstruction: Large atrium may splay the left main stem bronchus

Physical Diagnosis

• Loud S1: Due to stenosis of the mitral valve
• Opening Snap: Occurs right after S2; the earlier the snap, the worse the stenosis
  • Indicates a larger gradient across the valve
• Murmur Characteristics:
  • Best heard at the apex
  • Low-pitched rumbling diastolic murmur
  • Louder on exhalation; softer with Valsalva
  • May be similar to Austin Flint murmur in aortic regurgitation
• P2: Increased due to pulmonary hypertension
• Right ventricular hypertrophy: Due to elevated pulmonary artery pressures

Diagnosis

• EKG Findings:
  • Enlarged RV and left atrium
  • Atrial fibrillation
  • Large QRS complexes in precordial leads (V1, V2, V3)
  • Large "up and down" components on P wave
• Chest X-Ray:
  • Double density sign due to left atrium enlargement
  • Cephalization or pulmonary edema

Key Diagnostic Tool

• Echocardiogram:
  • Visualizes the large left atrium and mitral valve flow obstruction
  • Measures pressure gradient
• Cardiac Catheterization: Used for further evaluation and surgical planning

Treatment

• Loop Diuretics: For fluid management
• Anticoagulation: Important for atrial fibrillation and preventing embolization
  • Use of Coumadin
  • Rate control is crucial
• Balloon Valvuloplasty:
  • Effective without calcification or regurgitation
• Mitral Valve Replacement:
  • Necessary with significant regurgitation
  • Requires anticoagulation, especially for mechanical valves
  • INR should be maintained between 2.5 to 3.5

Conclusion

• Understanding of mitral valve stenosis includes pathophysiology, symptoms, diagnosis, and treatment options.
• Importance of managing symptoms and preventing complications through appropriate interventions.