Congenital Mitral Insufficiency (Mitral Regurgitation)
Congenital mitral insufficiency is a rare cardiac malformation characterized by incomplete closure of the mitral valve during ventricular systole, leading to retrograde blood flow from the left ventricle to the left atrium.
Key Points
- Incidence: Accounts for <5% of all congenital heart defects
- Often associated with other cardiac anomalies (60-80% cases)
- Represents a spectrum of anatomical abnormalities affecting valve components
- Significant impact on left heart development and function
- Early recognition crucial for optimal outcomes
Anatomical Variations
Primary Anatomical Defects
- Leaflet Abnormalities:
- Leaflet dysplasia
- Accessory leaflet tissue
- Cleft mitral valve
- Double orifice mitral valve
- Absence or hypoplasia of leaflet segments
- Chordal Apparatus:
- Elongated chordae tendineae
- Shortened chordae
- Absent chordae
- Abnormal chordal attachments
- Anomalous insertion of chordae
- Papillary Muscle Abnormalities:
- Single papillary muscle
- Abnormal papillary muscle position
- Hypoplastic papillary muscles
- Direct papillary muscle-leaflet attachment
- Annular Abnormalities:
- Annular dilation
- Abnormal annular shape
- Calcification (rare in children)
Associated Cardiac Lesions
- Left-sided Lesions:
- Aortic valve disease
- Coarctation of aorta
- Left ventricular outflow tract obstruction
- Hypoplastic left heart syndrome
- Septal Defects:
- Ventricular septal defect
- Atrial septal defect
- Atrioventricular septal defect
Clinical Manifestations
Symptom Progression
- Neonatal Period:
- Respiratory distress
- Poor feeding
- Failure to thrive
- Cardiogenic shock in severe cases
- Infancy and Early Childhood:
- Recurrent respiratory infections
- Exercise intolerance
- Growth delay
- Easy fatigability
- Later Childhood/Adolescence:
- Decreased exercise capacity
- Dyspnea on exertion
- Palpitations
- Chest pain
Physical Examination
- Cardiac Auscultation:
- Holosystolic murmur at apex
- Radiation to axilla
- Third heart sound (S3)
- Displaced point of maximal impulse
- Signs of Heart Failure:
- Tachypnea
- Tachycardia
- Hepatomegaly
- Pulmonary rales
- Poor peripheral perfusion
- Growth Parameters:
- Weight percentiles
- Height percentiles
- Head circumference in infants
Diagnostic Evaluation
Imaging Studies
- Echocardiography:
- Primary diagnostic tool
- 2D Assessment:
- Valve morphology
- Annular dimensions
- Subvalvular apparatus
- Chamber sizes
- Color Doppler:
- Regurgitant jet characteristics
- Direction of flow
- Multiple jets if present
- Quantitative Measures:
- Regurgitant fraction
- Effective regurgitant orifice area
- Vena contracta width
- Cardiac MRI:
- Detailed anatomical assessment
- Accurate quantification of regurgitation
- Ventricular volumes and function
- Myocardial characterization
- Surgical planning
- Cardiac Catheterization:
- Hemodynamic assessment
- Pulmonary vascular resistance
- Left ventriculography
- Pre-operative evaluation
Additional Studies
- Electrocardiogram:
- Left atrial enlargement
- Left ventricular hypertrophy
- Rhythm abnormalities
- Chest Radiograph:
- Cardiomegaly
- Pulmonary venous congestion
- Left atrial enlargement
- Laboratory Studies:
- B-type natriuretic peptide
- Complete blood count
- Renal function
- Genetic testing if indicated
Treatment Approaches
Medical Management
- Heart Failure Therapy:
- Diuretics:
- Furosemide
- Spironolactone
- Afterload Reduction:
- ACE inhibitors
- Angiotensin receptor blockers
- Beta-blockers in selected cases
- Diuretics:
- Supportive Care:
- Nutritional support
- Growth monitoring
- Prevention of infections
- Developmental assessment
Indications for Intervention
- Absolute Indications:
- Symptomatic severe MR
- LV dysfunction (EF <60%)
- LV end-systolic dimension Z-score >2.5
- Pulmonary hypertension
- Relative Indications:
- New onset atrial fibrillation
- Progressive LA enlargement
- Exercise intolerance
Surgical Management
Preoperative Considerations
- Timing of Surgery:
- Symptom severity
- Ventricular function
- Associated lesions
- Growth potential
- Anatomical Assessment:
- Detailed imaging review
- Valve repair possibility
- Associated anomalies
Surgical Techniques
- Valve Repair Options:
- Annuloplasty:
- Complete rings
- Partial bands
- Suture annuloplasty
- Leaflet Procedures:
- Cleft repair
- Patch augmentation
- Edge-to-edge repair
- Chordal Procedures:
- Shortening
- Artificial chordae
- Transposition
- Annuloplasty:
- Valve Replacement:
- Mechanical valves
- Bioprosthetic valves
- Size considerations
- Growth potential
Outcomes and Follow-up
Postoperative Care
- Early Monitoring:
- Hemodynamic stability
- Valve function
- Rhythm monitoring
- Anticoagulation if needed
- Complications:
- Early:
- Bleeding
- Arrhythmias
- Low cardiac output
- Late:
- Repair failure
- Prosthetic valve dysfunction
- Endocarditis
- Early:
Long-term Follow-up
- Regular Monitoring:
- Clinical assessment
- Serial echocardiography
- Exercise testing
- Growth and development
- Quality of Life:
- Physical activity guidelines
- Educational support
- Psychological support
- Family counseling
Special Populations
Neonates and Infants
- Unique Considerations:
- Timing of intervention
- Size limitations
- Growth potential
- Nutritional support
Adolescents
- Transition of Care:
- Adult congenital care
- Lifestyle modifications
- Career counseling
- Sports participation
Pregnancy Considerations
- Pre-pregnancy Counseling:
- Risk assessment
Special Populations
Neonates and Infants
- Unique Considerations:
- Timing of intervention
- Size limitations
- Growth potential
- Nutritional support
Adolescents
- Transition of Care:
- Adult congenital care
- Lifestyle modifications
- Career counseling
- Sports participation
Pregnancy Considerations
- Pre-pregnancy Counseling:
- Risk assessment
- Medication adjustments
- Contraception options
- Genetic counseling
- Management During Pregnancy:
- Frequent monitoring
- Modified anticoagulation if needed
- Labor and delivery planning
- Multidisciplinary care approach
- Post-partum Care:
- Close surveillance
- Medication adjustments
- Breastfeeding considerations
- Long-term follow-up planning
Disclaimer
The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.
