Premature beats are the most common type of pediatric arrhythmia and are characterized by heart beats that originate at ectopic pacing points and appear earlier than normal, followed by a long compensatory interval. Depending on the location of the pacing point, there are four types: sinus, atrial, junctional and ventricular. Premature ventricular beats are the most common, followed by premature atrial beats, while premature junctional beats are rare. Sinus premature beats are difficult to distinguish from sinus arrhythmias on the electrocardiogram.
Detection rate of premature heart beats in pediatric patients
Premature beats are less common in pediatric patients than in adults, and Yang reported that 0.5-2.2% of normal children have premature beats. The Shanghai Pediatric Hospital studied 1179 ECGs of healthy infants and children and found 9 cases of premature beats, with an incidence of 0.76%. 200 children with premature beats were also observed, of whom 70% had ventricular premature, 20% had atrial premature, and 10% had junctional. According to Lyen and Rakh, the incidence of premature beats in healthy newborns was 0.06%. In contrast, 57 cases of ventricular premature (0.31%) and 31 cases of supraventricular premature (0.17%) were found in 18,401 cases in the Japanese national pediatric census electrocardiogram. In epidemiological surveys, the incidence of ventricular premature in normal healthy children is 10%-15% in 24-hour ambulatory electrocardiograms, which shows that the presence of premature beats is not very frightening, but the key is the cause and nature of premature beats.
The following are the common causes of premature heart beats
1. various infections that directly damage the myocardium: e.g. various myocarditis (viral, toxic)
2. various causes of myocardial diseases (hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, etc.) and organic heart diseases (congenital heart disease, rheumatic heart disease, etc.)
3, various causes of hypoxia
4.Dysfunction of plant nerves
5, mental factors
6.Drugs
7.Electrolyte imbalance
8.High blood pressure, hyperthyroidism
9.Cardiac catheterization
10, Intracardiac direct vision surgery
11. The true cause of most premature beats is difficult to identify
Determination of the nature of premature beats
Premature beats that have no adverse effects on the body and generally do not require treatment are often referred to clinically as simple premature beats, whereas premature beats that have effects on the body and should be treated are referred to as pathologic premature beats. The following are the differences between simple and pathological premature contractions.
1. Whether there is an underlying organic heart disease or not and if there is an etiology, then it is pathological premature beats.
2. whether there is a combined ECG abnormality, if so, it is pathological premature beats
3. Premature beats are also pathological if they have the following characteristics.
(1) Frequent premature contractions in association, paired or repeated with more than three premature contractions.
(2) Polymorphic premature contractions and premature contractions of multiple origin.
(3) Wide QRS deformity with a time limit >0.14 seconds or an amplitude <10 mm or lower than the r-wave amplitude in the same lead.
(4) Coexistence of various types of premature beats (ventricular, supraventricular).
(5) Premature beats with R on T or R on P phenomenon.
(4) Increased premature beats after exercise or during rapid heart rate are considered pathological.
Further tests to determine the nature of premature beats
If the nature of premature beats cannot be determined by history and 12-lead ECG, further tests can be performed as follows.
1. Exercise ECG: The exercise test is mostly performed in pediatric patients using an activity plate or a bicycle exercise monitor, or, if this equipment is not available, by squatting or going up and down stairs. When the heart rate increases to 150 beats/min or more and the premature beats disappear without other ECG changes, it is generally benign; when the heart rate increases, the premature beats are frequent and appear in pairs, polymorphic or short bouts, it is mostly pathological.
2. Ambulatory ECG monitoring: also known as Holter monitoring, is a method to record ECG continuously for 24-72 hours under active conditions. The current small and lightweight tape recording weighs only 300-500 grams, or even 100 grams, suitable for infants and children to wear. It has improved the diagnosis rate of difficult and complex arrhythmias and is important for differentiating benign and pathological premature beats.
Premature heartbeat treatment
1. Premature beats with a detectable cause are treated for the cause
2. Most premature beats have no basis in heart disease and no other causes can be detected, so they usually do not need medication and most of them can disappear after some time or even some years. The specific judgment is as follows.
Anti-arrhythmic drugs may not be used in the following cases
1. asymptomatic, with normal activity or found on physical examination
2, Premature beats are more frequent at night or at rest, and decrease after activity.
3, the heart is not large on chest X-ray, with normal appearance and normal intracardiac structure on ultrasound.
4.Electrocardiogram without other abnormalities except premature beats, normal cardiac function, and myocardial enzyme values within the normal range.
Treatment of malignant ventricular premature contraction (ventricular premature after resuscitation of sustained ventricular tachycardia or ventricular fibrillation, with organic heart disease).
1, such as mitral valve prolapse 50% occurrence of ventricular premature, 6% occurrence of non-sustained ventricular tachycardia, optional beta-blockers; dilated cardiomyopathy patients with ventricular premature up to 90%, high rate of sudden death, optional amiodarone; hypertrophic cardiomyopathy patients with ventricular premature, mortality in 3%-18%, oral amiodarone; digitalis-induced ventricular premature, can be sedated lidocaine or phenytoin sodium.
2. Asymptomatic supraventricular premature beats, including short bursts of atrial tachycardia, do not require treatment; if the patient has symptoms or causes supraventricular tachycardia, cardioplegia, digoxin or beta-AR blockers may be given.
Problems to be noted in treatment
1, ventricular premature beats when generally do not use digitalis drugs, but if the premature beats are caused by organic heart disease, there is heart enlargement, heart failure exists, maundiflora can improve cardiac function, reduce the number of premature beats, pay attention to supplemental potassium salts, pay attention to maundiflora poisoning.
2, congenital heart disease in children with more serious conditions, the occurrence of premature ventricular contractions may be due to significant hemodynamic changes caused by heart malformations, which must be actively treated.
3, ventricular premature occurs during cardiomyopathy, myocarditis or rheumatic heart inflammation, which may indicate that the hemodynamics are deteriorating, causing a period of heart failure.
4.The prognosis of ventricular premature contractions occurring in hyperkalemia is poor. prolonged QT interval, history of syncopal episodes and the occurrence of frequent ventricular premature should be treated actively.
5, early after cardiac surgery occurs monogenic ventricular premature, clinical significance is not very big, often can disappear on its own, do not need to give treatment; if it is frequent premature beats, or even appear short burst ventricular tachycardia, often give lidocaine intravenous drip. After radical surgery for tetralogy of Fallot, the appearance of premature ventricular contractions is often a danger signal and prone to sudden death, so effective treatment should be given.
6. The treatment of premature beats generally advocates the use of one antiarrhythmic drug alone, or no more than two when a combination is necessary.