Search results
Results from the WOW.Com Content Network
Normal T wave. In electrocardiography, the T wave represents the repolarization of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period. The last half of the T wave is referred to as the relative refractory period or vulnerable period.
Electrocardiography is the process of producing an electrocardiogram (ECG or EKG [a]), a recording of the heart's electrical activity through repeated cardiac cycles. [4] It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the heart [ 5 ] using electrodes placed on the skin.
The hexaxial reference system is a diagram that is used to determine the heart's electrical axis in the frontal plane.. In electrocardiography, left axis deviation (LAD) is a condition wherein the mean electrical axis of ventricular contraction of the heart lies in a frontal plane direction between −30° and −90°.
If lead b is positive, the electrical heart axis can be estimated to lie within the quadrant between axis of lead a and lead b. A simple tool to quickly identify axis deviation (Figure 3) is the popular mnemonic; Reaching for Right Axis Deviation and Leaving for Left Axis Deviation. This refers to the appearance of leads I and II.
The hexaxial reference system is a diagram that is used to determine the heart's electrical axis in the frontal plane. The hexaxial reference system, better known as the Cabrera system, is a convention to present the extremity leads of the 12 lead electrocardiogram, [1] that provides an illustrative logical sequence that helps interpretation of the ECG, especially to determine the heart's ...
A broad SA results when the heart undergoes pathological changes and is reflected in a discordant ECG. A large SA indicates an altered ventricular repolarization sequence, and may be the result of structural and functional myocardial changes that induce regional shortening in action potential duration and impaired ion channel functioning.
[1] [2] In the Wiggers diagram, the X-axis is used to plot time subdivided into the cardiac phases, while the Y-axis typically contains the following on a single grid: Blood pressure. Aortic pressure; Ventricular pressure; Atrial pressure; Ventricular volume; Electrocardiogram; Arterial flow (optional) Heart sounds (optional)
Different wave shapes generated by different parts of the heart's action potential The ECG complex. P=P wave, PR=PR interval, QRS=QRS complex, QT=QT interval, ST=ST segment, T=T wave Principle of ECG formation. The red lines represent the depolarization wave, not bloodflow. An electrocardiogram is a recording of the electrical activity of the ...