justopk.blogg.se - Waves complete v 12

High-takeoff is where there is widespread concave ST elevation, often with a slurring of the j-point (start of the ST segment).High-takeoff is also known as benign early repolarization. A mimic of ST elevation is high-takeoff.Here the ST depression will be downsloping (sometimes known as the “reverse tick” sign). ST segment depression may also be seen in digoxin toxicity.ST depression is normally due to ischaemia.To be significant the S-T segment must be depressed or elevated by 1 or more millimeters in 2 consecutive limb leads or 2 or more millimeters in 2 consecutive chest leads.

The ST segment can be normal, elevated or depressed.

The QRS can also be tall in young, fit people (especially if thin).

PR interval: 0.12 – 0.2 secs (3-5 small squares).

PR interval: Represents the time taken for excitation to spread from the sino-atrial (SA) node across the atrium and down to the ventricular muscle via the bundle of His.

What do the segments of the ECG represent? All boxes are based on the assumption that the paper speed is running at 25mm/sec, therefore 1 large square is equivalent to 0.2 secs and a small square to 0.04 secs. For the purpose of this we will look at lead II (see Figure 4). The ECG can be broken down into the individual components.

aVF = inferior territory (remember ‘F’ for ‘feet’).

The areas represented on the ECG are summarized below: The electrical activity on an ECG (EKG).įigure 3. This can often be seen in V4 (see Figure 3).įigure 2. If it is at 90 degrees then the complex is ‘isoelectric’ i.e. When the activity travels away from the lead the deflection is net negative. When electrical activity (or depolarisation) travels towards a lead, the deflection is net positive. These comprise 4 limb electrodes and 6 chest electrodes.įigure 1. The leads can be thought of as taking a picture of the heart’s electrical activity from 12 different positions using information picked up by the 10 electrodes. The 12-lead ECG misleadingly only has 10 electrodes (sometimes also called leads but to avoid confusion we will refer to them as electrodes). To start with we will cover the basics of the ECG, how it is recorded and the basic physiology. Having a good system will avoid making errors. As with all investigations the most important things are your findings on history, examination and basic observations.