The normal length of the QTc is generally less than 460 milliseconds, but this length can vary based on a child's gender, age, and activity and the day of testing While the QT interval is used as one part of LQTS diagnosis, individuals with normal intervals may have LQTS and those with long intervals may not have LQTS For example, at least 10 to 15 percent of individuals with LQTS2700interpreting an ECG Patients age, gender, race, body habitus, heart orientation and physiology can affect the axis of the heart Similarly, technicalities of procedure, posture, temperature, or eating can affect ECG interpretations This analysis was carried out on the normal individual group of another study We needed to knowECG signs of left atrial enlargement 3 Left axis deviation 2 QRS duration ≥90 milliseconds 1 Prolonged Rwave peak time V1V2 (right ventricle) ≥35 milliseconds V5 Pin On Ecg Milliseconds on ecg