Down syndrome electrocardiogram

There are no ECG findings associated with Down syndrome however 40-60 percent of patients with Down syndrome suffer from congenital heart defects the most common being atrial septal defect, atrioventricular septal defect, ventricular septal defect, and patent ductus arteriosus. The ECG findings in Down syndrome are of the aforementioned underlying congenital heart defects.

• There are no ECG findings associated with Down syndrome however 40-60 percent^[1][2] of patients with Down syndrome suffer from congenital heart defects the most common being atrial septal defect, ventricular septal defect, atrioventricular septal defect, and patent ductus arteriosus. The ECG findings in Down syndrome are because of the aforementioned underlying congenital heart defects.
• The ECG findings suggestive of an underlying congenital heart defects are:^[3]

Ventricular septal defect electrocardiogram

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.

Atrial septal defect electrocardiogram The ECG findings in atrial septal defect vary with the type of defect present.

• It may be normal with an uncomplicated ASD and a small shunt.
• Individuals with atrial septal defects may have a prolonged PR interval (a first degree heart block). The prolongation of the PR interval is probably due to the enlargement of the atria that is common in ASDs and the increased distance due to the defect itself.
• Incomplete and less frequently complete right bundle branch block (RBBB) is often present.
• Right ventricular hypertrophy (RVH) with strain suggests onset of pulmonary hypertension or associated pulmonic stenosis.
• The QRS complex may be slightly prolonged and has a characteristic rSr’ or rsR’ pattern that is contributed to the disproportionate thickening of the right ventricular outflow tract (the last portion of the ventricle to depolarize).

Lesion Specific Electrocardiogram Findings

• Ostium secundum ASD– Patients with ostium secundum ASDs often develop atrial fibrillation or atrial flutter, and this occurs with a higher incidence with increasing age and with pulmonary hypertension. 2 out of 3 patients with an ostium secundum ASD have right axis deviation, incomplete right bundle-branch block.
• Ostium primum ASD – The first degree heart block is found to happen more frequently with ostium primum ASD compared to the other types due to the involvement of Bundle of His present in the close proximity of the defect. Both of these can cause an increased distance of internodal conduction from the SA node to the AV node.^[4] Ostium primum ASDs are associated with a marked superior left axis deviation.
• Sinus venosus ASD – Individuals with a sinus venosus ASD exhibit a left axis deviation of the P wave (not the QRS complex). It is often associated with low atrial and junctional rhythms, abnormal P-wave axis.
• Familial ASD – Complete heart block may be present in association with familial ASD ^[5].

Atrioventricular septal defect electrocardiogram

• Rhythm: normal sinus rhythm, PVCs 30%
• PR interval: 1° AVB >50%
• QRS axis: Moderate to extreme LAD; normal with atypical
• QRS Configuration: rSr´ or rsR´
• Atrial Enlargement: Possible LAE
• Ventricular hypertrophy: Uncommon in partial; BVH in complete; RVH with Eisenmenger
• Particularities: Inferoposteriorly displaced AVN

Patent ductus arteriosus electrocardiogram

• An electrocardiogram will appear differently depending on the severity of disease onset. In general, one can expect:
• Small PDA: the EKG is normal.
• Medium-sized PDA: there is LVH, LA increase, prolonged PR interval and eventual atrial fibrillation.
• Large-sized PDA: is similar to that of a VSD complicated by pulmonary hypertension. One can also expect:
  • Evidence of LVH is decreased or absent because there is essentially normal volume work by the LV.
  • There is RVH instead with a large R wave in V1. No Rsr’ like ASD.
  • Marked right axis deviation is common.
  • Peaked RA p waves are present

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