Ventricular septal defects (VSD) are a type of cardiac defect associated with the heart's lower chambers (ventricles). The wall separating the right and left bottom chambers is partially or entirely missing.

There are five basic types of ventricular septum classifications:

  • Perimembranous (Paramembranous, Membranous): VSD immediately below and adjacent to the commissure between the anterior and septal leaflets of the tricuspid valve. It is closely associated with the bundle of His (conduction system of the heart) at its posterior and inferior corners. This defect often lies under the commissure between the non- and right-leaflets of the aortic valve can cause aortic valve damage.
  • Conoventricular (Subaortic, Infracristal): VSD frequently associated with malalignment of the conal septum (i.e., Tetralogy of Fallot with anterior malalignment, interrupted aortic arch with posterior malalignment). This defect extends more superiorly and anteriorly than a perimembranous VSD, but is also closely associated with the bundle of His (conduction system of the heart).
  • Subpulmonary (Supracristal, Conal, Intraconal): Defect in the conal septum, which lies immediately below the pulmonary valve and adjacent to the right coronary cusp of the aortic valve. This VSD has a high risk of damaging the aortic valve and requires surgical repair.  
  • Inlet (Atrioventricular Canal Type): VSD immediately below the atrioventricular valves (septal leaflet of the tricuspid/right AV valve). Commonly associated with a primum ASD and also may be related to a separate perimembranous VSD.
  • Muscular: VSD occurring in the muscular septum between the two ventricles of the heart. Many of these defects either close over time or are amenable to device closure. 

Symptoms

Ventricular septal defect symptoms depend primarily on the amount of blood flow traveling from the left side of the heart to the right side of the heart, referred to as a left-to-right shunt. The amount of shunting is related to the size of the defect, the resistance of the pulmonary vasculature combined with the resistance of the systemic vasculature. When too much blood goes to the lungs, they can get overworked, often seen a few weeks after birth when pulmonary resistance falls. Children may require medication to help the body remove "extra" fluid on the lungs associated with this over circulation. Additionally, if this connection is not fixed, the lungs can become permanently injured, and the child can develop pulmonary hypertension. 

Infants may show signs and symptoms of congestive heart failure such as breathing fast, difficulty or working hard to breathe, elevated heart rate, not taking feedings as well as other babies, not growing well for their age, being tired or sleeping more often than other babies. 

Spontaneous closure of VSDs can occur later in life. Still, their presence increases the risk for bacterial endocarditis (infection of the heart, which can spread throughout the body) and often require life-long surveillance for monitoring for valve damage.

Interventional/Surgical Techniques

The surgical approach involves a standard midline incision (sternotomy). A machine that allows the heart and lungs to rest (cardiopulmonary bypass) allows the surgery team to repair the area of concern. Surgical repair most commonly involves placing a patch of material, either biological or synthetic, to close the ventricular septal defect. 

Post-Operative Care

Monitoring in the post-operative period after a ventricular septal defect repair will include invasive lines, such as an arterial line and central venous line, to monitor blood pressure and deliver medications. Medications may be needed to control hemodynamics, provide sedation and maintain hydration during recovery. Perfusion is monitored by pulse oximetry and NIRS (near-infrared spectroscopy) probes. The breathing tube (endotracheal tube) can be removed before leaving the operating room. A chest tube(s) will be present to remove air, blood or fluid from around the heart or lungs. This tube will be removed in the ICU as soon as possible, typically the following day. 

The average length of hospital stay is around 5-7 days.