Records electrical differences between the left leg and left arm electrodes. The other three frontal plane limb leads are called the augmented Vector leads. this means that these next three electrodes, for all practical purposes have a zero potential and do not change during the cardiac cycle.

In addition to the three bipolar limb leads, there are three augmented unipolar limb leads. These are termed unipolar leads because there is a single positive electrode that is referenced against a combination of the other limb electrodes. In practice, these are the same electrodes used for leads I, II and III.

The same three leads that form the standard leads also form the three unipolar leads known as the augmented leads. These three leads are referred to as aVR (right arm), aVL (left arm) and aVF (left leg) and also record a change in electric potential in the frontal plane.

aug·ment·ed lead electrocardiogram recorded between one limb and two other limbs. The augmented leads are designated aVF, aVL, and aVR for recordings made between the foot (left), left arm, and right arm, respectively, and the other two limbs.

transitive verb. 1 : to make greater, more numerous, larger, or more intense The impact of the report was augmented by its timing. 2 : supplement She took a second job to augment her income. 3 grammar : to add an augment to (a verb form) (see augment entry 2)

The morphology of the P wave in lead aVR can be used to differentiate atrial tachyarrhythmias. A positive P wave in aVR during tachycardia favours atrioventricular nodal re-entry tachycardia (Figure 6) (11). A negative P wave in aVR suggests a focal right atrial tachycardia (Figure 7) (33).

Abstract. The aVR is often neglected lead. It is an unipolar lead facing the right superior surface. As all the depolarisations are going away from lead aVR, all waves are negative in aVR (P, QRS, T) in normal sinus rhythm.

An automatic voltage regulator (AVR) is an electronic device that maintains a constant voltage level to electrical equipment on the same load. The AVR regulates voltage variations to deliver constant, reliable power supply.

When the limb placement is wrong (right arm-left arm lead reversal) it can cause technical dextrocardia in the ECG. Lead aVR will show positive “P” and positive QRS but there will be normal progression of R from V1 to V616 (Figure 14).

Well, the 2 leads situated on the right and left wrist (or shoulders), AVr and AVL respectively, and the lead situated on the left ankle (or left lower abdomen) AVf, make up a triangle, known as “Einthoven’s Triangle”. Information gathered between these leads is known as “bipolar”.

Unipolar Leads

Normal range 120 – 200 ms (3 – 5 small squares on ECG paper). QRS duration (measured from first deflection of QRS complex to end of QRS complex at isoelectric line). Normal range up to 120 ms (3 small squares on ECG paper).

AVF

In right chest leads V1 and V2, the QRS complexes are predominantly negative with small R waves and relatively deep S waves because the more muscular left ventricle produces depolarization current flowing away from these leads. In V1 the QRS are positive with tall R waves.

The duration of the P wave should not exceed three small squares (0.12 s). The wave of depolarisation is directed inferiorly and towards the left, and thus the P wave tends to be upright in leads I and II and inverted in lead aVR. Sinus P waves are usually most prominently seen in leads II and V1.

The electrical activity on an ECG (EKG). The areas represented on the ECG are summarized below: V1, V2 = RV. V3, V4 = septum. V5, V6 = L side of the heart.

If the P wave is inverted, it is most likely an ectopic atrial rhythm not originating from the sinus node. Altered P wave morphology is seen in left or right atrial enlargement. The PTa segment can be used to diagnose pericarditis or atrial infarction.

The P wave represents the electrical depolarization of the atria. In a healthy person, this originates at the sinoatrial node (SA node) and disperses into both left and right atria.

The first deflection is the P wave associated with right and left atrial depolarization. Wave of atrial repolarization is invisible because of low amplitude. On this count the P wave is always positive in lead II and always negative in lead aVR during sinus rhythm.

Mobitz II occurs is when the P-R interval is fixed in duration, but some P waves are not followed by a QRS as illustrated in the second tracing below. This is an example of a 2:1 rhythm because there are two P waves for each QRS.

the R wave reflects depolarization of the main mass of the ventricles –hence it is the largest wave.

The R wave is the first upward deflection after the P wave and part of the QRS complex. If a right bundle branch block is present, there may be two R waves, resulting in the classic “bunny ear” appearance of the QRS complex. In this setting, the second R wave is termed “R’” or “R prime.”

Electrocardiographic poor R wave progression (PRWR) is found in patients with anterior myocardial infarction, left ventricular hypertrophy and right ventricular hypertrophy, and is also seen in apparently normal individuals.

Tall R waves in V1 can be caused by abnormal electrical conduction (RBBB or left-sided VT, which slowly spreads across the right ventricle, or a left-sided accessory pathway), loss of posterior myocardium (old or acute posterior MI) or chronic anterior hypertrophy (HCM), chronic or acute RV strain (RVH, PE), congenital …

R wave height > 3mm. R/S ratio > 0.7.