There are three main components to an ECG: the P wave, which represents the depolarization of the atria; the QRS complex, which represents the depolarization of the ventricles; and the T wave, which represents the repolarization of the ventricles.
What does each part of the ECG represent?
The P wave is a record of the electrical activity through the upper heart chambers (atria). The QRS complex is a record of the movement of electrical impulses through the lower heart chambers (ventricles). The ST segment shows when the ventricle is contracting but no electricity is flowing through it.
What does ECG measure physiology?
An ECG provides a measurement of the rate and rhythm of the heart. It also provides information about the health of the electrical system, the size of the heart chambers, and the supply of blood to the heart muscle (Hampton, 2008).
How do the components of an ECG relate to the physiology of the heart?
The ECG works by detecting and amplifying tiny electrical changes on the skin that occur during heart muscle depolarization. The output for the ECG forms a graph that shows several different waves, each corresponding to a different electrical and mechanical event within the heart.
What does the P wave represent physiologically?
The P wave represents the electrical depolarization of the atria. In a healthy person, this originates at the sinoatrial node (SA node) and disperses into both left and right atria.
How would you describe an ECG?
An electrocardiogram (ECG or EKG) records the electrical signal from your heart to check for different heart conditions. Electrodes are placed on your chest to record your heart’s electrical signals, which cause your heart to beat. The signals are shown as waves on an attached computer monitor or printer.
What are the parts of the EKG?
The main components of an EKG wave include the P wave, PR segment, QRS complex, ST segment, T wave, and TP segment.
How is each part of the cardiac cycle represented on the ECG tracing?
A typical ECG tracing of the cardiac cycle (heartbeat) consists of a P wave (atrial depolarization ), a QRS complex (ventricular depolarization), and a T wave (ventricular repolarization). An additional wave, the U wave ( Purkinje repolarization), is often visible, but not always.
What does the QRS represent on an ECG?
The QRS wave is produced by the atrioventricular node (AV). The P wave in an ECG complex indicates atrial depolarization. The QRS is responsible for ventricular depolarization and the T wave is ventricular repolarization.
Which of the following components of an ECG represents ventricular repolarization?
T wave. T waves represent ventricular repolarization (atrial repolarization is obscured by the large QRS complex).
Which component of an ECG represents ventricular diastole?
The Purkinje fibers, relay the electrical impulse directly to ventricular muscle, stimulating the ventricles to contract (ventricular systole). Repolarization of the SA node is also spread throughout the atria, and then the ventricles, starting the relaxation phase (ventricular diastole).
What part of the ECG reflects the depolarization of the ventricles and repolarization of the atria?
Atrial and ventricular depolarization and repolarization are represented on the ECG as a series of waves: the P wave followed by the QRS complex and the T wave. The first deflection is the P wave associated with right and left atrial depolarization. Wave of atrial repolarization is invisible because of low amplitude.
What does ST segment on ECG represent?
The ST segment is an interval between ventricular depolarization and ventricular repolarization. It is identified as the end of the QRS complex to the beginning of the T wave. The end of the T wave to the beginning of the P wave is described as the TP segment, which is the zero potential or isoelectric point.
How do you identify a pathological Q wave?
Q waves are considered pathological if: > 40 ms (1 mm) wide. > 2 mm deep. > 25% of depth of QRS complex.
What does the T wave represent in ECG?
The T wave on the ECG (T-ECG) represents repolarization of the ventricular myocardium. Its morphology and duration are commonly used to diagnose pathology and assess risk of life-threatening ventricular arrhythmias.
What is AP wave on an ECG?
P Wave. The P wave represents the depolarization of the left and right atrium and also corresponds to atrial contraction.