define ECG draw one ECG and write the major events shown in the figure
Answers
an ECG is a test that detects and records the strength and timing of the electrical activity in your heart. This information is recorded on a graph that shows each phase of the electrical signal as it travels through your heart.
An electrocardiogram (ECG) is a simple test that can be used to check our heart's rhythm and electrical activity. Sensors attached to the skin are used to detect the electrical signals produced by our heart each time it beats. It is also used to quickly detect heart problems and monitor our heart's health.
The first attachment shows the ECG of a healthy person
Each peak in the ECG is identified with a letter from P to T that corresponds to a specific activity of the heart.
Look at the second attachment for a better understanding!
1. The P-wave represents the electrical excitation (or depolarisation) of the atria, which leads to the contraction of both the atria.
2. The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole.
3. There is no distinctly visible wave representing atrial repolarization in the ECG (TA wave) because it occurs during ventricular depolarization. Because the wave of atrial repolarization is relatively small in amplitude (i.e., has low voltage), it is masked by the much larger ventricular-generated QRS complex.
4. The T-wave represents the return of the ventricles from excited to normal state (repolarisation). The end of the T-wave marks the end of the systole.
Note: I forgot to mark it, but T-wave (or U-wave) actually represents ventricular repolarisation (in the second attachment)!
