Why the electric lead is connected to the left ankle?
Answers
I don't know sorry please ask to other people
* When the average vector (direction of depolarization) is moving toward the positive pole of the electrode, the QRS complex will be upright on the ECG. Note that in lead II, the right arm is the negative pole and the left foot is the positive pole. This represents the general flow of electrical current through the heart, because, anatomically, the sino-atrial (SA) node is approximately at the right arm and the apex of the left ventricle is roughly on the same plane as the left foot. For this reason, one is able to see the P, QRS, and T waves best in lead II. Lead II is also the most commonly used lead for bedside monitoring.
* When the average vector is moving away from the positive pole of the electrode, the QRS complex is negative.
* When the average vector is moving perpendicular (at a right angle) to the positive pole of the electrode, the QRS will be biphasic (above and below the baseline).
* The more directly an electrical impulse comes toward or away from an electrode, the greater the amplitude or height of the QRS complex.
* The QRS complex in leads I, II, III, aVL, and aVF are normally upright, with aVR normally downward.
* The R wave in the precordial leads should progress from very small in V1 to very tall in V6. This is termed as "R-wave progression," and when not present, it suggests an abnormality that is most commonly an old anterior wall myocardial infarction (MI) or left bundle branch block (LBBB).
* A Q wave is the first negative deflection after the PR interval, and may be normal or abnormal depending on its size and shape.