What does this wave marked by an arrow in the ECG represents?
A. Ventricular Depolarisation
B. Ventricular Repolarisation
C. Atrial Depolarisation
D. Atrial Repolarisation
Ans:B. Ventricular Repolarisation.
The wave marked by an arrow in the ECG represents T wave.
|P wave||The p-wave represents depolarization of the atria. Atrial depolarization spreads from the SA node towards the AV node, and from the right atrium to the left atrium.|
|PR interval||The PR interval is measured from the beginning of the P wave to the beginning of the QRS complex. This interval reflects the time the electrical impulse takes to travel from the sinus node through the AV node.|
|QRS complex||The QRS complex represents the rapid depolarization of the right and left ventricles. The ventricles have a large muscle mass compared to the atria, so the QRS complex usually has a much larger amplitude than the P-wave.|
|J-point||The J-point is the point at which the QRS complex finishes and the ST segment begins.|
|ST segment||The ST segment connects the QRS complex and the T wave; it represents the period when the ventricles are depolarized.|
|T wave||The T wave represents the repolarization of the ventricles. It is generally upright in all leads except aVR and lead V1.|
|Corrected QT interval (QTc)||The QT interval is measured from the beginning of the QRS complex to the end of the T wave. Acceptable ranges vary with heart rate, so it must be corrected to the QTc by dividing by the square root of the RR interval.|
|U wave||The U wave is hypothesized to be caused by the repolarization of the interventricular septum. It normally has a low amplitude, and even more often is completely absent.|