What are deflections on an ECG?
A wave that travels toward a positive lead will result in an upward or positive deflection (tracing) on the ECG, and a wave traveling away from a positive lead will result in a downward or negative deflection.
Why are Q and S waves downward deflections?
This is due to the passage of depolarization wave down the interventricular septum, and through the septum from left to right, upward from the apex, and through the lateral walls of the ventricles.In a typical ECG, the Q wave is the initial downward deflection.
What is aVR aVL and aVF?
aVR means augmented Vector Right; the positive electrode is on the right shoulder. aVL means augmented Vector Left; the positive electrode is on the left shoulder. aVF means augmented Vector Foot; the positive electrode is on the foot.
What does polarization of the heart mean?
Theory. Heart muscle cells are polarized at rest. This means the cells have. slightly unequal concentrations of ions across their cell membranes.
What leads bipolar?
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”.
Why is lead aVR used?
The lead aVR is a very important lead in localisation of Coronary Artery Disease. In the presence of anterior ST elevation, ST elevation in lead aVR and V1 denotes proximal LAD obstruction where ST elevation is more in lead V1, than in aVR.
Why is Pqrst used in ECG?
He chose the letters PQRST to separate the tracing from the uncorrected curve labeled ABCD. The letters PQRST undoubtedly came from the system of labeling used by Descartes to designate successive points on a curve.
What is the Pqrst wave?
The sinoatrial node (SA) is the pacemaker of the heart and produces the P wave. The QRS wave is produced by the atrioventricular node (AV). The P wave in an ECG complex indicates atrial depolarization. The QRS is responsible for ventricular depolarization and the T wave is ventricular repolarization.
What is V3 in ECG?
V3, V4 = septum. V5, V6 = L side of the heart. Lead I = L side of the heart. Lead II = inferior territory.
How is AVf calculated?
aVF=EF – 1/2 (EL + ER) [10].
What happens when the heart is depolarized?
What is meant by depolarization of the heart? Depolarization of the heart is the orderly passage of electrical current sequentially through the heart muscle, changing it, cell by cell, from the resting polarized state to the depolarized state until the entire heart is depolarized.
What is polarization in medical term?
Medical Definition of polarization : the action of polarizing or state of being or becoming polarized: as. a(1) : the action or process of affecting radiation and especially light so that the vibrations of the wave assume a definite form. (2) : the state of radiation affected by this process.
Is there any deflection on an electrocardiogram?
One does NOT see any deflection on the ECG during the time that the sinoatrial node is being depolarized. The depolarization of the atrioventricular node and the His-Purkinje system also does not generate any electrical activity that is detectable in the ECG.
Why does an ECG show positive or negative deflection?
This is due to each lead recording the electrical activity from different directions. When the electrical activity of the heart travels towards a lead you get a positive deflection. When the electrical activity travels away from a lead you get a negative deflection.
What do you need to know about ECG waves?
Log in or Register. ECG interpretation requires firm knowledge of the characteristics of the normal ECG. The waves, intervals, durations and assessment of rhythm is fundamental to ECG interpretation. Below follows a brief summary of the ECG waves, their appearance, terminology, physiological background and interpretation. Figure 1.
What does early repolarization of an ECG look like?
Early Repolarization A usually benign ECG pattern with an incidence of 5 to 13% of people so very common especially in young healthy athletes ST elevation (J point elevation) of 1 mm or more in 2 or more contiguous leads (usually inferior or lateral or both) ST morphology similar to pericarditis