Characteristics of various types of electrocardiogram -22 medical and health interview materials

electrocardiogram (ECG or EKG) is a technique to record the pattern of electrical activity changes produced by the heart in each cardiac cycle from the body surface with an electrocardiograph. In the examination of practicing skills of medical practitioners, the content of electrocardiogram is often tested, and some questions are set in different heart problems, which is sometimes difficult for students to judge in the examination. Therefore, experts from Tianjin Health Talent Network have summarized relevant knowledge points for everyone, hoping to help candidates review.

1. Normal ECG: ECG characteristics of sinus rhythm: P wave appears regularly, and the shape of P wave shows that the excitation comes from sinus node (that is, P wave stands upright in leads I, II, aVF and V4 ~ V6, and inverted in lead aVR). The frequency of sinus rhythm in normal people fluctuates physiologically, and the normal range of resting rhythm is generally defined as 6 ~ 1 beats/min.

2. Sinus tachycardia: frequency of sinus rhythm >; 1 beats/min, PR interval and QT interval were shortened accordingly.

3. Sinus bradycardia: frequency of sinus rhythm <; 6 times/minute.

4. Atrial premature contraction: (1) ectopic P' wave appears before atrial premature contraction, and its shape is different from sinus P wave; (2)P'R interval >; .12s; (3) Most of them are incomplete compensatory intervals, and the interval between two sinus P waves after immediate pre-contraction is less than twice that of normal PP..

5. Atrial fibrillation: (1) Normal P waves disappear and are replaced by fibrillation waves (F waves) with different sizes and shapes; (2) The frequency is 35 ~ 6 times/minute; (3)RR is absolutely irregular, and QRS wave generally does not widen.

6. Paroxysmal supraventricular tachycardia: sudden and sudden, with a frequency of 16 ~ 25 beats/min, fast and regular rhythm, and normal QRS morphology.

7. Ventricular extrasystole: (1) QRS-T wave front before ventricular extrasystole has no P wave or related P wave; (2) QRS malformation with large shape before the stage, the time limit is usually >; .12s, the direction of T wave is mostly opposite to that of QRS main wave; (3) It is often a complete compensatory interval, and the distance between the two sinus P waves before and after immediate premature contraction is equal to twice the normal PP distance.

8. Ventricular tachycardia: (1) The frequency is mostly 14 ~ 2 beats/min, and the rhythm can be slightly irregular; (2) The 2)QRS complex is wide and deformed, and the time limit is usually >; .12s; (3) If P wave can be found, and the frequency of P wave is slower than that of QRS wave, and there is no fixed relationship between PR (atrioventricular separation), the diagnosis can be confirmed; (4) Occasionally atrial excitation captures the ventricle or ventricular fusion wave occurs.

9. Ventricular fibrillation: QRS-T wave disappears completely, and low wavelets with different sizes and extremely uneven frequency of 2 ~ 5 beats/min appear.

1. atrioventricular block: (1) I degree atrioventricular block with prolonged PR interval > .2s。 (2) Type I atrioventricular block of degree II, P wave appeared regularly, and PR interval gradually extended until a QRS complex fell off. (3) Type Ⅱ atrioventricular block, with constant PR interval (normal or prolonged) and five QRS complex after partial P wave. (4)Ⅲ atrioventricular block, P wave has nothing to do with QRS wave (PR interval is not fixed), and atrial rate is faster than ventricular rate.

11. Acute myocardial infarction: pathological Q wave (time limit? .3s, amplitude? 1/4R), the arch back of ST segment is raised upward. Chest lead: V1-V6 lead: extensive anterior wall; Lead V1-V3: anterior septal wall; V3-V5 leads: anterior wall; V4-V6: front side wall; V7-V9 leads: posterior wall. Limb conduction: ⅱ, ⅲ, avF: inferior wall; I. avL: high side wall.