Pediatric multifocal atrial tachycardia
Introduction
Introduction to multi-source atrial tachycardia in children Chaoticatrialtachycardia (CAT), also known as multi-source atrial tachycardia or disordered atrial rhythm, occurs mostly in infancy, usually with normal heart structure, persistent seizures, difficult drug cardioversion However, it can be relieved by itself and the prognosis is good. Adult cases occur in the elderly, often accompanied by chronic obstructive pulmonary disease, severe condition and poor prognosis, which are significantly different. basic knowledge The proportion of illness: the incidence rate is about 0.0035% Susceptible people: infants and young children Mode of infection: non-infectious Complications: cardiomyopathy, heart failure
Cause
Causes of multi-source atrial tachycardia in children
(1) Causes of the disease
The cause of this disease is unclear, may be related to autonomic dysfunction or viral infection. It is also believed that the neonatal heart conduction system is not fully developed, histological and pathophysiological changes are likely to lead to arrhythmia, in addition, viral myocarditis, Respiratory distress syndrome, low calcium, etc. can also induce the disease, and its mechanism may be related to atrial pacing point shift or atrial block.
(two) pathogenesis
The disease is common in the perinatal period of normal heart structure, neonatal and infancy patients, its occurrence may be related to the development of atrial muscle action potential and self-discipline variation, animal experiments suggest that the neonatal animal atrial muscle action potential time is shorter The maximum diastolic potential is lowered and the plateau period is short, and the vulnerability of the atrial muscle is increased. The external stimulation may cause repeated reactions. Compared with the clinically observed neonates and adults, the atrial muscle refractory period is shorter. The conduction velocity is faster and consistent. In addition, the parasympathetic innervation of the baby's heart is dominant, and the sympathetic innervation is imperfect. The autonomic nervous system is not well-developed, which can also lead to the vulnerability of the atrial muscle. With the heart tissue and its autonomic nerves. The phylogeny is getting better and better, and the infantile ventricular atrial tachycardia can often recover spontaneously. All kinds of congenital heart disease, myocardial disease, rheumatic valvular disease and high altitude heart disease can have disordered atrial tachycardia. It has been reported. Digitalis poisoning caused disordered atrial tachycardia with varying degrees of atrioventricular block, we saw a congenital neck, chest lymph In patients with squamous cell carcinoma, preoperative routine electrocardiographic examination revealed a transient disordered atrial tachycardia. The mechanism of ventricular atrial tachycardia is still unknown. It may be due to the excitability and refractory period of atrial tissue. Differences, the formation of atrial micro-reentry loop; it has also been suggested that triggering activity can play a role in the occurrence of turbulent atrial tachycardia.
Prevention
Multi-source atrial tachycardia prevention in children
Active prevention of congenital heart disease; prevention and treatment of electrolyte imbalance and acid-base imbalance, active treatment of primary disease, such as various gastrointestinal disorders, uremia, rheumatic fever, Kawasaki disease, nervous system factors, hypothermia, anesthesia and drug poisoning caused by arrhythmia .
Complication
Complications of multi-source atrial tachycardia in children Complications cardiomyopathy heart failure
Can be complicated by cardiomyopathy, heart enlargement, heart failure.
Symptom
Pediatric multi-source atrial tachycardia symptoms common symptoms arrhythmia heart murmur heart enlargement pale pale irritability restless limbs cold heart tachycardia heart failure shock
The age of onset is small, mostly in infancy, a few occur in the mother's uterus, and misdiagnosed as intrauterine distress, patients with normal heart often have no symptoms, because of regular health check or respiratory infection, the heart rate is fast, irregular rhythm, often It lasts for several months to several years, usually relieves itself at the age of 3, and has a good prognosis. Some infants have arrhythmogenic cardiomyopathy due to persistent tachycardia, heart enlargement, heart failure, and patients with heart disease. Symptoms are related to basic heart disease. Because persistent tachycardia can aggravate heart failure, the prognosis depends on the severity of the original heart disease. Some patients have no ventricular rate and no hemodynamic changes, and there is no clinical manifestation. Some children have fast ventricular rate, irritability in clinical manifestations, pale complexion, cold limbs, and even shock. Some of them can be treated for primary disease. Clinical cardiac signs: abnormal heart rhythm, heart sounds are different, low blunt, Some audible noises, some have systemic manifestations of heart failure.
Examine
Pediatric multi-source atrial tachycardia examination
General cases of routine examination without abnormalities, severe cases can be found hypoxemia, acidosis, hypocalcemia and so on.
1. ECG characteristics
(1) In line with adult CAT characteristics: ECG performance is consistent with the diagnostic criteria for adult dysfunctional atrial tachycardia:
1 There are at least 3 or more different forms of P waves on the same lead.
2 Do not see the dominant pacemaker.
There is an equipotential line between 3P-R.
4P-R interval, RR interval and PP interval.
5 atrial rate is fast, children are 140 ~ 300 times / min, an average of 210 times / min.
(2) Pediatric CAT has the following characteristics: In addition to the above-mentioned specific manifestations of electrocardiogram, pediatric disordered atrial tachycardia has the following characteristics:
1 often accompanied by short-term atrial flutter (atrial rate 350 ~ 450 beats / min), atrial fibrillation (atrial rate 400 ~ 700 beats / min) and atrial premature contraction (monomorphic and polymorphic), disordered atrial There is no obvious order relationship between the tachycardia and the above three atrial arrhythmias.
2 ventricular rate of 110 ~ 200 times / min, an average of 130 times / min.
3 due to rapid ectopic rhythm caused by overspeed inhibition, the common cardiac arrest reached 1.00 ~ 1.20s.
2. Chest film
In heart failure, the heart enlarges and the pulmonary congestion appears.
3.B Ultra
In heart failure, liver enlargement, congestion, echocardiography, can be found in the heart of congenital malformations, cardiac dysfunction and other primary cardiac disease manifestations.
Diagnosis
Diagnosis and diagnosis of multi-source atrial tachycardia in children
According to the typical electrocardiogram or 24h dynamic electrocardiogram, the diagnosis of turbulent atrial tachycardia can be confirmed. Secondly, echocardiography should be performed to determine the possible cause.
It should be differentiated from atrial fibrillation and flutter.
1. Atrial fibrillation: atrial rate of 350 beats / min or more, the equipotential disappearance between PR, with atrioventricular block.
2. Atrial flutter: atrial rate of 250 beats / min or more, the equipotential disappearance between PR, atrial wave is F waveform, and with atrioventricular block.
