How to check for premature heart beats?

All patients should pay attention to the examination of premature heart beats, because sometimes they may be symptoms caused by other diseases, such as atrial premature beats, atrioventricular junctional premature beats and multi-source premature beats. Common examinations include electrocardiogram.

1. Atrial premature beats.

2. Premature beats at the atrioventricular junction.

3. Ventricular premature beats, with premature QRS complexes with abnormal morphology, mostly lasting ≥ 0.12 seconds, T wave opposite to the main wave of the QRS complex, S-T segment shifted with the direction of the T wave, no related P wave in front of it, and complete compensatory interval. Ventricular premature beats can occur between two sinus beats, forming insertional ventricular premature beats.

4. Multifocal premature beats.

5. Parallel rhythm-type premature beats and ventricular premature beats can help diagnose myocardial infarction.

6. Electrocardiogram examination performance

(I) In atrial premature beats, the P wave appears early, and its shape is different from the P wave of the basic heart rhythm. The PR interval is greater than 0.12s. The QRS wave is mostly the same as that of the sinus rhythm, sometimes slightly widened or deformed, accompanied by corresponding changes in ST and T waves. This is called intraventricular differential conduction, which needs to be differentiated from ventricular premature beats. When atrial premature beats are accompanied by intraventricular differential conduction, an early and deformed P' wave can be seen before the deformed QRS wave group. There may also be no corresponding QRS wave after the premature and deformed P' wave. This is called blocked atrial premature beat, which needs to be differentiated from sinus arrhythmia or sinus arrest. If a deformed premature P' wave is found on the ST segment or T wave of the previous heartbeat, it can be diagnosed as blocked atrial premature beat. Atrial premature beat impulses often invade the sinoatrial node, causing the latter to depolarize prematurely. The sinoatrial node depolarizes spontaneously and then restarts according to the original cycle, forming an incomplete compensatory interval. Occasionally, a complete compensatory interval is seen after atrial premature beats.

(III) Ventricular premature beats: The QRS complex appears early with abnormal morphology and a duration of more than 0.12s. The T wave is opposite to the main QRS wave and ST is displaced with the T wave without a P wave in front of it. Ventricular premature beats occur at the proximal bundle branch and their QRS complex may not be widened. There is usually a complete compensatory interval after the ventricular premature beats. When the basic heart rate is slow, the ventricular premature beats may be inserted between two sinus beats to form insertional ventricular premature beats. Occasionally, the retrograde P' wave of the ventricular premature beats that is transmitted back to the atria often appears on the ST segment of the ventricular premature beats.