Shunt flows from high pressure left ventricle to low pressure right ventricle.

  Shunt flow follows the
left ventricle - right ventricle - pulmonary artery - left atrium - left ventricle route.

  ECG changes reflect hemodynamic changes caused by the shunt flow.

  ECG may be normal if the VSD is small.

ECG abnormalities that may be observed in patients with VSD

  Right atrial abnormality (RAA).

  Left atrial abnormality (LAA).

  Right ventricular hypertrophy (RVH).

  Complete or incomplete right bundle branch block (RBBB).

  Left ventricular hypertrophy (LVH).

  If VSD is large,
S1S2S3 pattern may be observed.

Katz-Wachtel phenomenon ( sign ): large biphasic (equiphasic) QRS complexes observed in midprecordial and limb leads. Sum of the amplitudes of R and S waves in leads C2, C3 or C4 is > 60mm (6mV).

Katz-Wachtel phenomenon is seen when pulmonary hypertension and the resultant biventricular hypertrophy developes.

ECG in patients with VSD and Eisenmenger syndrome

  Signs of right ventricular hypertrophy (RVH) are observed more frequently. Signs of left ventricular hypertrophy (LVH) may also accompany.

  The rhythm is generally

  Right atrial abnormality (RAA) may be seen.

ECG abnormalities in adult patients who have been operated for closure of the VSD during their childhood

  Right bundle branch block: 50-90% if operated by right ventriculotomy, 40% if operated by right atrial approach.

  Complete atrioventricular (AV) block (very rare).

  In this group of patients, the risk of sudden cardiac death has been reported to increase in patients with
left axis deviation on ECG and/or ventricular arrhythmias on Holter monitoring.


  Chou's Electrocardiography in Clinical Practice. Adult and Pediatric. 5th ed. Philadelphia. WB Saunders. 2001.

  Am Heart J 1961;62:842.

  Am J Cardiol 1959;3:721.

  Am J Cardiol 1965;16:359.

  Am Heart J 1960;60:195.

  Acc Curr J Review 2003;12:97-100.

  Am Heart J 1937;13:202.

  Am J Cardiol 1972;28:679.

ECG 1. The ECG above, belongs to an 11 years old child who has been operated for ASD, VSD and coarctation of the aorta.
Katz-Wachtel phenomenon (biventricular hypertrophy pattern) is also seen.

Dr. Mahmut Gokdemir has donated this ECG to our website.

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ECG 2. This ECG belongs to a 49 years old woman who was operated for VSD and pulmonary stenosis.

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ECG 3. Twenty years old man with VSD, pulmonary stenosis and mitral stenosis. The ECG shows right bundle branch block and
first degree AV block.

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ECG 4. The above ECG belongs to an 8 years old boy. He was operated for Transposition of the Great Arteries and Ventricular
Septal Defect (VSD) when he was 1 year old. VSD closure operations increase the risk of right bundle branch block.

Dr. Mahmut Gokdemir has donated this ECG to our website.

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ECG 5. The ECG above belongs to a 30 years-old man with kyphoscoliosis and pectus excavatum.
He has a large (1.4 cm wide) unoperated subaortic VSD.
Color-Doppler ECHOcardiography did not show clear-cut shunt flow suggesting equalization of ventricular pressures.
ECHOcardiography also showed hypokinesia of some left ventricular (LV) segments (mild LV systolic dysfunction).
The patient had clubbing of the fingers.
This ECG shows several signs of right ventricular hypertrophy: R/S ratio in C5 and C6 is <1,
S1S2S3 pattern, right atrial abnormality, S in C5 is >0.7mV (>7mm).
The amplitude of the P wave in lead II is >2.5mm denoting right atrial abnormality.

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ECG 6. The ECG above belongs to an 8 years-old girl with restrictive VSD.
ECHOcardiographic signs of pulmonary hypertension was NOT observed.

Pediatric cardiologist Prof. Dr. Nazlihan Gunal has donated the above ECG to our website.

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