Question

Identify the mechanical activities that result from the electrical activity of the ECG components.

• P wave:

• QRS complex:

•T wave:

• P-R interval:

• P-R segment:

• ST segment:

• QT interval:

• ST interval:

• U wave:

• T-P segment:

Answer 1

P wave :The electrical signal begins in the sinoatrial node and travels to the right and left atria, causing them to contract and pump blood into the ventricles. Atrial depolarization

QRS complex : Represents ventricular depolarization ( the contraction of the ventricles and ejection of blood out of the heart and into the large arteries exiting the heart.)

T wave :This wave results from ventricular repolarization and signals the beginning of ventricular relaxation.

P-R interval : It is the time, in seconds, from the beginning of the P wave to the beginning of the QRS complex and it represents time between the onset of atrial depolarization and the onset of ventricular depolarization.

P-R segment : It is the flat line between the end of the P-wave and the start of the QRS complex, The P-R segment reflects the time delay between atrial and ventricular activation

ST segment : This segment starts at the end of the QRS wave and ends at the start of the T wave.  During the ST segment, all the ventricular myocardium is depolarized.

QT interval : It represents the time during which the ventricles are stimulated and recover after the stimulation. This interval shortens at a faster heart rate and lengthens at a slower heart rate.

ST interval : is an interval between ventricular depolarization and ventricular repolarization.

U wave : Is a small deflection immediately following the T wave, the exact source of U wave is not known but it could represent repolarization of the Purkinje fibers

T-P segment : It is region from the end of the T wave to the beginning of the P wave. It represents the time when the heart muscle cells are electrically silent. TP interval shortens when the heart rate increases and vice versa.