Non-paroxysmal junctional tachycardia

Introduction to non-paroxysmal transitional tachycardia Nonparoxysmaljunctional tachycardia (NPJT), also known as accelerated junctional tachycardia (AYT), accelerated intercourse escape rhythm, etc. Pick is equal to the first report in 1957 for atrioventricular transfer Tachycardia caused by increased self-discipline in the district. basic knowledge The proportion of the disease: the incidence rate is about 0.003% - 0.007%, more common in patients with hypertension Susceptible people: no special people Mode of infection: non-infectious Complications: arrhythmia

Non-paroxysmal transitional tachycardia

(1) Causes of the disease

Non-paroxysmal transition tachycardia almost always occurs in patients with structural heart disease, such as coronary heart disease, acute myocardial infarction (especially inferior myocardial infarction), myocarditis, cardiomyopathy, chronic pulmonary heart disease , especially co-infection, heart failure, hypertensive heart disease, bacterial endocarditis, diabetic acidosis, hypokalemia, digitalis poisoning, cardiac surgery, anesthesia, cardiac catheterization, coronary angiography Neutral and electrolyte imbalance can affect the blockage of the atrioventricular junction, causing different degrees of hypoxia, ischemia, inflammation, degeneration, necrosis, etc., resulting in increased self-discipline in the junction area and NPJT, a small number of patients with unknown causes. Some patients are normal.

According to the characteristics of clinical electrocardiogram, NPJT is divided into two categories. The causes of these two types are different, as follows:

NPJT (35%) without dissection of the atrioventricular:

The patient's age ranged from 8 to 66 years old, and about 38.1% were seen in normal people. Some were caused by selective inhibition of the vagus nerve on the sinus node. Most of the other cases were found in chronic and stable heart disease. The most common coronary heart disease (22.2%) ), followed by congenital heart disease (such as atrial septum, ventricular septal defect, corrective large blood vessel ectopic, etc.), a small number of patients with perivascular disease, when NPJT occurs, mostly transient, usually only recorded by an electrocardiogram It disappears at the time of review. The causes are acute infection, electrolyte imbalance, uremia, etc. Among them, heart rate is mostly 60-69 times/min. This type of NPJT is a relatively benign arrhythmia.

NPJT (20%) with combined atrioventricular dissection (compartmental separation):

The patients were 7 to 71 years old, and the vast majority (97.2%) were found in organic heart disease and systemic diseases. About 2.8% of them were normal, most of them were found in patients with acute heart damage or digitalis overdose. The probability of occurrence is from large to small. There are: intracardiac surgery, digitalis overdose, rheumatic fever, acute myocardial infarction, coronary heart disease, pulmonary heart disease and pneumonia, pulmonary bursitis, uremia, acute gastroenteritis, etc. Except for a small number of patients with chronic heart disease (such as cardiomyopathy, coronary heart disease), NPJT can last for a long time or irregular, all are transient, disappear within a few hours, several days, combined with atrioventricular dislocation can be divided into the following In four categories, the causes are not the same.

(1) simple atrioventricular dislocation: most of the heart or body disease, such as patients after direct surgery, rheumatic fever, cardiomyopathy, acute myocardial infarction patients, pheochromocytoma patients with hypertensive crisis, etc., NPJT For a transient, disappear within hours or days.

(2) Atrioventricular dislocation combined with atrioventricular block: more heart disease, the most common digital rehmannia, followed by intracardiac surgery, rheumatic fever, cardiomyopathy and acute myocardial infarction, pulmonary heart disease.

(3) sinus node and junction area alternately control the atrial and ventricular more heart damage performance: coronary heart disease, cardiomyopathy is more common.

(4) double-crossing tachycardia: more common in coronary heart disease, cardiomyopathy.

(two) pathogenesis

NPJT is an ectopic pacemaker that occurs in the atrioventricular junction. In the pathological state, the autonomic increase in the pacemaker is caused by the level of sinus node, which is often caused by a slight decrease in sinus rhythm. The escape of the junction area begins. When the sinus heart rate is accelerated, the NPJT can be suspended or terminated. In addition, there is a lack of afferent protection mechanism around the pacemaker point in the sinus node and the junction area. When either frequency is too fast, it can invade each other. , causing the rhythm of the other pacemaker to rectify.

Non-paroxysmal transition tachycardia prevention

1. Because non-paroxysmal tachycardia is more common in digitalis poisoning, it is necessary to master the indications when using digitalis drugs. The blood concentration and clinical symptoms should be closely monitored during the treatment. deal with.

2. When the atrioventricular tachycardia occurs in the non-paroxysmal transitional tachycardia, because the atrial contraction can not help the ventricular filling to reduce the cardiac output, then consider the use of atropine to increase the sinus rhythm, through the sinus - The competition of heart rhythm in the junction area makes the non-paroxysmal transitional tachycardia disappear, the separation of the atrioventricular compartment disappears, and the cardiac output increases.

Non-paroxysmal transition tachycardia complications Complications arrhythmia

The frequency of non-paroxysmal transition tachycardia is similar to sinus rhythm. There is no obvious change in hemodynamics. This arrhythmia is often temporary, so it is a benign arrhythmia, usually without special treatment. It often disappears with the improvement of the primary disease. NPJT does not cause atrial fibrillation or ventricular fibrillation.

Non-paroxysmal transitional tachycardia symptoms Common symptoms tachycardia frequent atrial premature beats

Because the frequency of NPJT is 70-130 times/min, there is no significant effect on hemodynamics. Most patients are asymptomatic, and a few people may have palpitations; more patients have arrhythmia from sinus to atrioventricular transfer. When the tachycardia is over-speed, it feels itchy, coughing, palpitations, and the symptoms disappear after the seizure stops. There are no other special positive signs except for the signs of basic heart disease.

1. The heart rhythm has the characteristics of the atrioventricular junction area: retrograde P wave (II, III, P wave inversion on aVF lead; V1P wave upright); P wave can be before, during or after QRS wave, PR spacing is less than 0.12 seconds , QRS wave normal range (can have indoor differential conduction).

2. The ventricular rate is 70-130 beats/min, most of which is between 70 and 100 beats/min.

3. The room is out of touch.

4. Sinus rhythm captures the ventricle.

According to the above points, non-paroxysmal atrioventricular junction tachycardia can be diagnosed.

Non-paroxysmal transition tachycardia

Mainly rely on ECG diagnosis.

1. Typical ECG characteristics of non-paroxysmal transitional tachycardia

(1) A series of crossover P waves and QRS waves for more than 3 consecutive times: the frequency is 70-130 times/min. In general, the rhythm is uniform and the RR interval is equal.

(2) The P' wave is retrograde, and the P'-R interval can be <0.12s before the QRS wave; or after the QRS wave, the RP' interval is <0.20s; it can also overlap with the QRS wave. Invisible, PII, PIII, PaVF inverted, PaVR, PV1 upright (Figure 1).

(3) sinus agitation often captures the ventricle: the formation of incomplete atrioventricular dislocation, the QRS wave captured by the ventricle appears in advance, with sinus P wave before it, P'R interval > 0.12s, can also form intermittent Interfering atrioventricular dislocation, ie sinus-crossing zone competition phenomenon (Figure 2).

(4) NPJT is a gradual onset, slow stop: when the carotid sinus is compressed, the heart rate can only be temporarily slowed down, and outing block can also occur.

2. Detailed description of typical ECG features

(1) The frequency of NPJT is usually 70 to 130 times/min, and is mostly about 100 times/min. It has also been proposed that the frequency is 60 to 150 times/min.

(2) QRS waves are supraventricular: malformations can also occur, often accompanied by differential conduction in the room, or with bundle branch block or pre-excitation syndrome. The RR interval is basically uniform, but not It is fixed, and sometimes the out-of-way block can occur after the excitement of the junction area, causing the ventricular rhythm to become uneven.

(3) Competition phenomenon in sinus-intersection area: When the sinus rhythm coexists with the QRS wave in the junction area, there will be competition between the two, showing incomplete interfering atrioventricular separation (disjointed).

3. NPJT's ECG type

(1) NPJT without atrioventricular dislocation: characterized by atrial and ventricular, controlled by the rhythm of the junction zone, with retrograde P' wave before or after the QRS wave, or no P' wave visible due to overlap of the P' wave with the QRS wave (Fig. 1), if the junction area is excited to go out of block, sinus P wave can be captured to capture the ventricle, which is sinus escape.

(2) NPJT with dissociated atrioventricular dislocation: ECG is controlled by the rhythm of the junction area with a frequency of 60-150 times/min, all of which have different forms and degrees of dislocation of the atrioventricular, depending on the form of dissection of the atrioventricular compartment. For the following four categories:

1 Simple atrioventricular dislocation: the atrium is controlled by the sinus node, the ventricle is controlled by the rhythm point of the junction area, the ventricular rate exceeds the atrial rate, and there is no conduction block. This is due to the reverse conduction block in the junction area, but only the reverse conduction block. The forward conduction controls the ventricle, which may be complete: it may also be incomplete, as in some cases it may manifest as intermittent sinus activation of the ventricle (Figure 3).

2NPJT and sinus rhythm competition alternately appear sinus node and the frequency of the junction area is similar: the performance of the sinus node and the junction area competition, alternating control of the ventricle (intermittent atrioventricular dislocation), which is a more common type, NPJT occurs only when the frequency of the junction area increases beyond the sinus rhythm. Therefore, NPJT occurs when sinus bradycardia (frequency is less than 130 beats/min) or sinus conduction block, once sinus When the heart rate increases, it disappears (Figures 4, 5).

3 atrioventricular dislocation combined with atrioventricular block: the atrium is controlled by sinus node or ectopic rhythm (atrial fibrillation), and the ventricle is controlled by the atrial junction, the atrial rate exceeds the ventricular rate, but the atrial agitation cannot capture the ventricle. The most common is atrial fibrillation with non-paroxysmal atrioventricular junction tachycardia, which is characterized by complete afferent block in the atrioventricular junction, so the junctional activation controls the ventricle but has reverse conduction resistance. At this time, the electrocardiogram shows the QRS wave regularity, while the retrograde P wave disappears and is replaced by the atrial fibrillation wave (Fig. 6). Sometimes the excitation in the junction area can cause forward conduction block, which can occur 2:1 or 3. : 2 conduction block or Venturi phenomenon, at this time the ventricular rate is irregular (Figure 7, 8).

4 double sexual intercourse tachycardia: two rhythm points in the junction area respectively control the atria (retrograde P' wave) and ventricle at different frequencies, and are disconnected from each other, the atrial rate can be greater or less than the ventricular rate, generally more intermittent .

Diagnosis and diagnosis of non-paroxysmal transitional tachycardia

The identification of escape rhythm and non-paroxysmal atrioventricular transition tachycardia in the atrioventricular junction, the two are mainly in frequency, the former ventricular rate is 40 ~ 60 times / min, is the passive rhythm of the atrioventricular junction; The latter ventricular rate is faster than or equal to 70 times / min and not reached 140 times / min, also known as accelerated handover heart rate.

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