Ventricular Septal Defect (VSD)

A hole connecting the 2 ventricles

Acyanotic

Left-Right Shunt

Causes

•          Congenital (prevalence 2:1000 births) à most common congenital cardiac malformation
•          Acquired (post-MI)

Type

1.       Membranous VSD (90%)

2.       Muscular VSD

3.       Single Ventricle

Clinical Feature

Small VSDs : asymptomatic & usually close spontaneously, with 90% no longer patent by 10 years of age

Moderate VSDs : Fatigue & SOB with cardiac enlargement & prominent apex beat.

                                 Palpable systolic thrill at lower left sternal edge & loud ‘tearing’ pansystolic murmur heard at the same position.

Large VSDs : cause pulmonary HPT (may lead to Eisenmenger’s syndromeà central cyanosis & finger clubbing)

** loud ‘tearing’ pansystolic murmur produced by flow from high pressure LV to low pressure RV during systole.It’s best heard at left sternal border.

On PE (auscultatory finding)

Small VSDs (‘maladie de Roger’) : Loud & sometimes Long Systolic Murmur

Moderate VSDs : loud ‘tearing’ pansystolic murmur

Large VSDs : cause pulomonary HPT & soft murmur

Cx

• AR
• IE
• Pulmonary HPT
•  Eisenmenger’s complex (In this condition, a ventricular septal defect (VSD) exists in conjunction with pulmonary vascular obstructive disease (PVOD). The resistance to blood flow to the lungs involved in PVOD causes a "right to left shunt" to occur, in which blood flows from the right ventricle into the left ventricle through the VSD)

Ix

§                             ECG

o   normal (small VSD)

o   LAD + LVH (moderate VSD)

o   LVH + RVH (large VSD)

§                           CXR

o   Normal heart size +- mild pulmonary plethora (small VSD)/ cardiomegaly

o   Large pulmonary arteries

o   Marked pulmonary plethora (large VSD)

Mx

1. Small VSD require no specific tx.only IE prophylaxis should be advised
2. Surgical repair of the defect
3. Cardiac failure should be treated with:

a.      Digoxin

b.      Frusemide

Tetralogy of Fallot’s

EPIDEMIOLOGY

Most common causes of cyanotic congenital heart disease

Most common CHD that survive (10%)

Four typical features of TOF

1. VSD

2. Pulmonary stenosis

3. Right ventricular hypertrophy

4. Aorta overriding VSD

CLINICAL FEATURES

Symptoms

            Dyspnoea and fatigue is main presentation

After exercise (hypoxic cell), child usually adopt a squatting position because it can increases peripheral vascular resistance and decreases the degree of Rt to Lt shunt.

Growth retarded

On CVS examination

            Central cyanosis (commonly present from birth)

            Clubbing of finger and toes + polycythaemia (obvious after 12 months)

            Auscultation : systolic ejection murmur at Lt upper sternal border

PATHOPHYSIOLOGY

With substantial obstruction of the Rt ventricular outflow tract, blood is shunted thru the ventricular septal defect from right to left. Thus the patient will presented with central cyanosis.

INVESTIGATION

CXR shows RV hypertrophy & small pulmonary artery (classic boot-shaped heart)

ECG shows RV hypertrophy with Rt bundle branch block (RBBB)

Echocardiography shows discontinuity between aorta and anterior wall of ventricular septum

CT & MRI give valuable information for planning the surgery

Boot-shaped heart

TREATMENTS

Without intervention (mortality rate 95% by age 20)

            Give 02 and place knee-chest position

            Morphine can sedate the child + relaxing the outflow of pulmonary

            Long term B-blocker may be needed

            Give endocarditis prophylaxis

With intervention ( survival rate is 90-95% by age 20)

In infants (palliative procedure usually done before age 1 yr) – an anastomosis  between subclavian artery and pulmonary artery (Blalock shunt), in order to increase blood supply to the lungs.  

Older child – A complete surgical correction is required.

REFERENCES
1.  Kumar P, Clark M, editors. Kumar and Clark Clinical Medicine, 7th ed.
2. Mohammad Inam Danish, editor. "Medical Diagnosis and Management"

3. Longmore,editor. “Oxford handbook of Clinical Medicine”