Right axis normal in first 6 months of life
Blood shunted away from pulm vasculature in utero, higher pulmonary pressures--> relatively thicker RV --> Right axis
Extreme superior axis
Axis of -90 - 180 degrees
Seen with AV canal or atrial septal defects
AVF lead vector
Negative QRS vector in AVF seen in some cardiac malformations (e.g. AV septal defects, single ventricle
Biphasic QRS in AVF can be normal but should be reviewed by peds cards cardiology review. [Evans, 2010]
Blood shunted away from pulm vasculature in utero, higher pulmonary pressures--> relatively thicker RV --> Right axis
Axis of -90 - 180 degrees
Seen with AV canal or atrial septal defects
Negative QRS vector in AVF seen in some cardiac malformations (e.g. AV septal defects, single ventricle
Biphasic QRS in AVF can be normal but should be reviewed by peds cards cardiology review. [Evans, 2010]
ECG 
Cardiac enzymes
Cardiac ultrasound
D-dimer
Transcutaneous pacing
Defibrillation
Pulmonary artery catheter
IVC ultrasound