Makindo Medical Notes

Related Subjects: |Congenital Acyanotic Heart Disease |Congenital Cyanotic Heart Disease |Cardiac Embryology |Cyanosis - Central and Peripheral |Down's syndrome (Trisomy 21) |Tetralogy of Fallot |Patent Foramen Ovale (PFO) |Ventricular Septal defect (VSD)

Small VSDs may produce loud murmurs, and large VSDs may produce no murmur at all but will cause heart failure, usually at 6+ weeks. Many smaller VSDs close without any treatment.

About

• Abnormal shunt between the left ventricle (LV) and right ventricle (RV).
• Seen in 2/1000 live births, making it the most common congenital heart disease.
• Harsh, loud pansystolic blowing murmur ± thrill.

Aetiology

• Size of the defect and pulmonary pressures determine the clinical picture.
• Increased pulmonary flow can result in pulmonary hypertension, which then reduces flow.
• Can lead to Eisenmenger's syndrome, where reversal of flow causes cyanosis.

Anatomical Types

• Perimembranous VSD: The most common type, located in the membranous portion of the ventricular septum, near the tricuspid and aortic valves. Can vary in size and is often associated with aortic valve prolapse or insufficiency. May close spontaneously, especially in smaller defects.
• Muscular VSD: Occurs in the muscular portion of the septum, lower in the ventricular septum, away from the valves. Often referred to as "Swiss cheese" VSD when multiple small defects are present. These defects have a high chance of spontaneous closure.
• Inlet (Atrioventricular Canal) VSD: Located near the tricuspid and mitral valves, in the area where blood enters the ventricles from the atria. Commonly associated with atrioventricular septal defects (AVSD) and Down syndrome. Surgical intervention is often required.
• Outlet (Supracristal or Subarterial) VSD: Located near the outflow tracts of the right and left ventricles, beneath the pulmonary and aortic valves. Less common, more frequent in Asian populations. Associated with aortic valve prolapse, which may necessitate early surgical repair.
• Gerbode VSD: Rare type of VSD that involves a direct communication between the left ventricle and the right atrium. This type of defect is unusual and often requires surgical correction due to the significant left-to-right shunt it causes.

Clinical

• Loud, harsh pansystolic murmur/thrill at the lower left sternal border.
• Hyperdynamic LV apex beat, pulmonary edema.
• Poor weight gain, fatigue after feeding. Look for signs of endocarditis.
• Eisenmenger's syndrome - murmur reduces, RV failure.
• High risk of endocarditis, so be vigilant.
• RV hypertrophy with lift and volume overloaded LV.
• Small VSDs create loud murmurs, and large VSDs create soft murmurs.

Investigations

• Bloods: Raised WCC/ESR/CRP may suggest endocarditis. U&E and LFTs: usually normal.
• CXR: Normal with small VSD but cardiomegaly, enlarged pulmonary arteries, increased vascular markings, and possibly edema.
• ECG: Normal if small; otherwise, RVH and LVH.
• Echocardiogram: Can anatomically locate the VSD and estimate pulmonary artery pressures.

Management

• Observation: Close monitoring of the VSD without immediate intervention. Small defects are likely to close spontaneously without intervention. This is particularly applicable to small muscular VSDs in infants.
• Medications: Use of drugs such as IV/PO diuretics, ACE inhibitors, and digoxin to manage fluid overload and heart failure. These can alleviate symptoms prior to definitive surgery and are used when surgery is delayed or not immediately necessary.
• Surgical Repair: Open-heart surgery to close the VSD using a patch or sutures. Indicated for large defects causing significant symptoms, failure to thrive, or increased pulmonary blood flow. Surgery is often performed in early childhood.
• Transcatheter Device Closure: A minimally invasive procedure where a device is inserted through a catheter to close the VSD. Typically used for muscular VSDs or residual VSDs after surgery. It’s less invasive than open-heart surgery and involves a shorter recovery time.
• Endocarditis Prophylaxis: Antibiotic therapy to prevent infective endocarditis, particularly in patients with certain types of VSD or after surgical repair. Recommended for individuals with VSD who have a history of endocarditis or those who have undergone VSD repair with residual defects.
• Long-term Follow-up: Regular cardiac evaluations to monitor for complications such as residual defects, arrhythmias, or pulmonary hypertension. Essential for all patients with a history of VSD, regardless of whether they have undergone surgical or transcatheter repair.

Complications

• Endocarditis
• Heart failure
• Arrhythmias