Common terminology for ECG paper

Composition of each band of the ECG

1. P wave
Because the sinus node is located at the junction of the right atrium and superior vena cava, sinus node excitation is first transmitted to the right atrium and then to the left atrium via the ventricular bundle, forming a P wave across the atrium. ECG. The P wave represents atrial excitation, with the first half representing right atrial excitation and the second half representing left atrial excitation. P-wave time limit was 0.12 s and height was 0.25 MV. When the atria are enlarged, with abnormal conduction in both chambers, the P wave can appear as a spike or bimodal P wave.

2. PR interval
The PR interval (PR) represents the time required for the sinus node to generate excitation that reaches the ventricle through the atria, atrioventricular junction, and atrioventricular bundle, so that the ventricular myocardium begins to excite. The normal PR interval was between 0.12 and 0.20 sec. When conduction from the atrium to the ventricle is blocked, it manifests as prolongation of the PR interval or disappearance of the ventricular waves after the P wave.

3. QRS complexes
Going down through the His bundle and the left and right bundles and simultaneously the Ciji right and left ventricles form the QRS complex. The QRS complex represented ventricular de jirization, and the Jihuo time frame was less than 0.11 seconds. When left or right bundle block, ventricular enlargement or thickening occurs, the QRS complex will broaden, deform, and extend the time frame.

4. J point
Intersection of the end of the QRS with the beginning of the ST segment. This means that all ventricular myocytes had been completely dejiminated.

5. ST segments
Ventricular muscle dejirization is complete and re jirization has not begun for some time. At this time point ventricular myocardium was in a dejionized state with no potential difference between cells. Therefore, the ST segment should normally be on the isoelectric line. When ischemia or necrosis occurs in a certain part of the myocardium, there is still a potential difference after the completion of dejirimination. At this time on ECG showed ST segment shift.

6. T wave
The subsequent T wave represents the ventricular re Ji. Before the main QRS, the T wave should be in the same direction as the main QRS. Changes in the T wave on the electrocardiogram are influenced by several factors. For example, myocardial ischemia can manifest as low T-wave inversion. A shrunken T wave may be seen with hyperkalemia, hyperacute phase of acute myocardial infarction, etc.

7. U wave
U waves can be seen after T waves in some leads and are currently thought to be related to ventricular re-ji.

8. QT interval
Represents the time of ventricular depolarization to repolarization. The normal QT interval was 0.44 sec. Because the QT interval is affected by heart rate, the concept of corrected QT interval (QTC) was introduced. Prolongation of the QT interval is frequently associated with the occurrence of malignant arrhythmias.