Overview of NPJT
Nonparoxysmal Pleiotropic Junctional Tachycardia (NPJT) is also known as Accelerated Pleiotropic Junctional Tachycardia and Accelerated Pleiotropic Escape Rhythm. The heart rate is 70 to 130 beats per minute, but most do not exceed 100 beats per minute. NPJT almost always occurs in patients with organic heart disease, and most patients are asymptomatic, while a few may experience palpitations.
Etiology
Non-paroxysmal zonal tachycardia almost always occurs in patients with organic heart disease. For example, coronary heart disease acute myocardial infarction (especially lower wall myocardial infarction), myocarditis, cardiomyopathy, chronic pulmonary heart disease patients, especially the combination of infection, heart failure, hypertensive heart disease, bacterial endocarditis, diabetic acidosis, hypokalemia, digitalis toxicity, cardiac surgery, anesthesia, the process of central catheterization in the process of coronary arteriography, as well as electrolyte disorders, and other factors can be involved in the atrioventricular junction area Blockade, causing varying degrees of hypoxia, ischemia, inflammation, degeneration, necrosis, etc., leading to an increase in autoregulation of the junction zone and the occurrence of NPJT.The cause of the disease is unknown in a few patients. Some patients do not have organic cardiac disease.
Symptoms
Since the frequency of NPJT is 70-130 beats per minute, it has no obvious effect on hemodynamics, and most of the patients are asymptomatic, while a few may have palpitation sensation; occasionally, when the heart rhythm changes from sinus to atrioventricular junctional tachycardia, the patients feel itchy throat, coughing constantly, and palpitation, and the symptoms disappear when the attack stops. There are no special positive signs other than those of underlying heart disease.
Examination
Typical electrocardiographic features of nonparoxysmal junctional zone tachycardia:
1. more than 3 consecutive alternating P waves with QRS waves
The frequency is 70-130 beats/minute, and in general the rhythm is homogeneous and the R-R intervals are equal.
2. P-waves are retrograde in nature
May be before the QRS wave, then the P-R interval 1 upright.
3. Sinus excitation often seizes the ventricle
Incomplete atrioventricular disconnection is formed, the QRS wave captured by the ventricle appears in advance and is preceded by a sinus P-wave, with a P-R interval of >0.12 s. Intermittent interferential atrioventricular disconnection can also be formed, i.e., sinus-crossing zone competition phenomenon.
4. NPJT is gradual onset, slow cessation of
Compression of the carotid sinus can only slow down the heart rate temporarily, and outgoing block can also occur.
Diagnosis
1. The rhythm is characterized by atrioventricular junction zone origin, with retrograde P waves (inverted P waves on II III and aVF leads; upright V1 P waves); P waves can be before, during or after QRS waves, PR spacing is less than 0.12s, and QRS waves are in the normal range (intraventricular differentiation of conduction can be present).
2. ventricular rate is between 70 and 130 beats per minute.
3. Atrioventricular disconnection.
4. sinus rhythm seizes the ventricles.
On the basis of these points, a diagnosis of nonparoxysmal atrioventricular disconnected tachycardia can be made.
Differential Diagnosis
Differential of atrioventricular junction zone escape rhythm and nonparoxysmal atrioventricular junction zone tachycardia, the two differences are mainly in the frequency. The former has a ventricular rate of 40 to 60 beats per minute and is a passive rhythm in the atrioventricular interface zone, while the latter has a ventricular rate faster than or equal to 70 beats per minute without reaching 140 beats per minute and is also known as an accelerated interfacial heart rate.
Treatment
The frequency of nonparoxysmal zonal tachycardia is very similar to that of sinus rhythm, and this arrhythmia is mostly temporary, so it is a benign arrhythmia and usually does not require special treatment. NPJT does not cause atrial or ventricular fibrillation. Therefore, the treatment mainly focuses on the cause of the disease and the primary disease.
Digitalis toxicity caused by should immediately stop the use of digitalis, while the application of potassium salts, phenytoin sodium. When NPJT occurs when digitalis is used in patients with atrial fibrillation, it often suggests digitalis overdose or toxicity. If the ventricular rate is too fast can be used beta-blocker procainamide, etc., but should be avoided in the presence of heart failure. If the heart rate is too fast or heart failure is present and digitalis has not been used, digitalis can be used, but should be closely observed. When atrioventricular separation (deregulation) occurs, because atrial contraction does not help ventricular filling to reduce cardiac output, atropine may be considered to increase sinus rhythm. Through the competition of the sinus-junctional rhythm, the NPJT and atrioventricular separation disappear, and the cardiac blood output can be increased.
Prognosis
Non-paroxysmal sinus tachycardia is not likely to cause significant hemodynamic changes, does not cause atrial or ventricular fibrillation, and is mostly transient, so the prognosis is better. It often improves or disappears after eliminating the cause. However, if there is a severe atrioventricular deregulation will cause hemodynamic changes and need to be actively managed.
Because non-paroxysmal sympathetic regional tachycardia is often seen in digitalis intoxication, so in the use of digitalis drugs to grasp the indications, the treatment process should be closely monitored blood concentration and clinical symptoms, once the problem is found in a timely manner to deal with.