ECG findings in VSD

ECG findings in VSD

ECG findings in ventricular septal defect (VSD) depend on the size of defect, magnitude of the left to right shunt and severity of pulmonary hypertension. ECG is normal in small ventricular septal defects with small left to right shunts [1].

Left atrial enlargement may be noted in moderately restrictive VSDs and in those with large left to right shunts. Left axis deviation is common with inlet VSDs and AV septal defects. Left axis deviation may also be seen in about 5% of moderately restrictive VSDs. Ventricular septal aneurysms and multiple VSDs (Swiss cheese ventricular septum) can be associated with left axis deviation.

Biventricular enlargement (Katz – Wachtel phenomenon) can be seen in large VSD [2]. The Katz-Wachtel sign is tall diphasic RS complexes at least 50 mm in height in lead V2, V3 or V4 – mid precordial leads [3]. Large anterior electrocardiographic forces are due to the hypertrophied right ventricle and late posterior forces due to the hypertrophied left ventricle [4]

A study of 110 isolated ventricular septal defects evaluated by cardiac catheterization and oximetry has given detailed description of ECG findings in VSD [5]. Notching of the P waves was noted in more than one third of the cases. Notching and broadening of the P wave in lead I or II and terminal P inversion in V1 indicated left atrial overload. It was associated with tall R or deep Q indicating left ventricular volume overload. R wave voltage in V6 greater than maximum for the age and voltage of S in V1 greater than maximum for age were considered features of left ventricular overload. Voltage of R in V1 and S in V6 greater than maximum for age were considered features of right ventricular overload.

References

1. Dack S. The electrocardiogram and vectorcardiogram in ventricular septal defect. Am J Cardiol. 1960 Feb;5:199-207.
2. Katz LN and Wachtel H. The diphasic QRS type of electrocardiogram in congenital heart disease. Am Heart J; 1937, 13: 202-206. (Available at ScienceDirect)
3. Elliott LP, Anderson RC, Tuna N, Adams P, Neufeld HN. Complete Transposition of the Great Vessels: II. An Electrocardiographic Analysis. Circulation; 1963; 27:1118-1127. (Free full text available at: https://www.ahajournals.org/doi/abs/10.1161/circ.27.6.1118)
4. Varriale P, Kennedy RJ, Alfenito JC. Vectorcardiogram of combined ventricular hypertrophy: posterior counterclockwise loop (Frank system). Br Heart J. 1969 Jul;31(4):457-61. (Free Full Text at Pubmed Central).
5. Vince DJ, Keith JD. The electrocardiogram in ventricular septal defect. Circulation. 1961 Feb;23:225-40.