What Is Ventricular Response?

Premature beat (also known as premature beat, extra-periodical contraction, referred to as premature beat). It is an early ectopic heartbeat. According to the origin, it can be divided into four types: sinus, atrial, atrioventricular junction and ventricular. Among them, the most common is ventricular, followed by atrial, premature sinus beats are rare. Premature beats are common ectopic rhythms. Can occur on the basis of sinus or ectopic (such as atrial fibrillation) rhythm. Occasionally or frequently, it can occur irregularly or regularly after each or a few normal beats, forming a dual or premature beat.

Premature heart beat

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Premature beat

Premature pulsations may be asymptomatic, and palpitations or palpitation may also be present. Frequent premature

This can happen in a number of ways.

(I) Abnormal impulse formation due to abnormal autonomy Under certain conditions, such as the sinus impulse reaching the ectopic pacing point, due to the Weidensky phenomenon, the threshold potential is reduced and the diastolic depolarization slope is changed. Causes premature pulsation. The permeability of the fibrous cell membrane of the diseased atrium, ventricle, or Pujiye to different ions changes the fast-response fibers into slow-response fibers, and the diastole is automatically depolarized, which accelerates autonomy and enhances self-discipline.

(2) Reentry phenomenonCircular reentry or focal microreentry has the same premature pulsation pattern if the reentry route is the same; if the conduction velocity is the same during reentry, the pairing time of the premature pulsation and the previous pulsation is fixed.

(Three) parallel contraction

(Four) triggering activities (triggered activity)

Etiology

Premature pulsations can occur in normal people. However, patients with cardiac neurosis and organic heart disease are more likely to occur. Emotional agitation, nervousness, fatigue, indigestion, excessive smoking, alcohol or strong tea can cause seizures, and there is no obvious cause. Digitalis, barium, quinidine, sympathomimetics, chloroform, ring Toxic effects such as propane anesthetics, potassium deficiency, and cardiac surgery or cardiac catheterization can be caused. Coronary heart disease, advanced mitral valve disease, heart disease, myocarditis, hyperthyroid heart disease, and mitral valve prolapse are often prone to premature beats.

The principles of treatment should be determined with reference to the presence or absence of organic heart disease, whether it affects cardiac output and the possibility of developing severe arrhythmia.

Most premature beats without organic heart disease require special treatment. Symptoms should be relieved. Sedatives and -blockers can be tried with premature pulsation induced by tension and excessive emotion or exercise.

Those with frequent attacks, obvious symptoms or accompanied by organic heart disease, should find out the etiology and inducement of premature beat as soon as possible, and give corresponding etiology and inducement treatment, meanwhile correctly identify its potential fatal possibility, and actively treat the cause and symptomatic treatment.

In addition to the treatment of the cause, antiarrhythmic drugs can be used. Most of the premature beats at the atrial and atrioventricular junctions are selected for the a, Ic, , and IV drugs at the atrial and atrioventricular junctions, and the premature ventricular contractions are mostly used Class I and III drugs in the ventricle (see Drug Classification above, see also Chapter 7 "Introduction to Clinical Pharmacology"). Potentially fatal ventricular premature beats often require urgent intravenous administration. Ib is preferred. Intravenous lidocaine is often preferred in the early stages of acute myocardial infarction. If there is no contraindication after myocardial infarction, -blockers are often used. In patients with primary or secondary QT interval prolongation syndrome, Class I drugs are contraindicated. -blockers, phenytoin, or carbamazepine can be selected for primary patients. If the cause is removed in secondary cases, isoproterenol or atrial or ventricular pacing should be used.

Recent studies (CAST 1989) have suggested that antiarrhythmia increases the risk of increased mortality. Even if patients with heart disease control ventricular premature beats, there is no evidence to reduce the sudden death rate (except for beta blockers after myocardial infarction). Therefore, the use of anti-arrhythmic drugs should be weighed against its advantages and disadvantages. There have been large series of multi-center trials in non-myocardial infarction patients (mainly premature beats) in the country, followed up for a long period of time, and supraventricular arrhythmia is commonly used for propafenone, morexazine, and ventricular arrhythmia Rupidone, Morexazine, and Mexiletine have certain effects. No serious cardiac events have been found, but the effects and possible adverse reactions need to be closely followed up during the medication. Caution is especially needed for those with heart dysfunction.