Ventricular septal defect electrocardiogram

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Associate Editors-In-Chief: Keri Shafer, M.D. [mailto:kshafer@bidmc.harvard.edu]; Atif Mohammad, M.D., Priyamvada Singh, MBBS

Electrocardiogram

The ECG changes reflect the size of shunt and degree of pulmonary hypertension

Small VSD(restrictive VSD, Qρ/Qѕ < 1.5/1.0 Qρ/Qs is pressure gradient between pulmonary and systemic circulation): EKG is normal. A few patients will have an rsr' in V1.

Medium-sized VSD:


 * left atrial overload - broad notched P wave
 * Left ventricular overload - Deep 'Q' wave, tall 'R' wave, tall 'T' wave in lead V5 and V6
 * Atrial fibrillation can also be seen

Large VSD:


 * In adults or adolescence with a large VSD and pulmonary vascular obstructive disease, LVH is absent because volume overload of the LV is no longer present. Large VSD will produce right ventricular hypertrophy with right axis deviation. At this point there is either an rsR' pattern in the right precordial leads, or more  commonly, a tall monophasic R wave in the right precordial leads reflecting RVH. Also deep S waves in the lateral precordial leads and tall peaked P waves.

In patients with an acquired infundibular stenosis, the EKG shows a pattern of RVH similar to the tracing of patients with tetralogy of Fallot.