Frequent premature ventricular contractions

Introduction Ventricular premature contraction refers to ventricular activation, which is also called ventricular ectopic pulsation, which is caused by the pacemaker branch below the His bundle. It is the most common arrhythmia in children, caused by reentry or self-discipline. Frequently (>6 beats / min or 30 beats / hour), continued to appear in the law, continuous occurrence of 2-3 premature beats, showing multi-source or short-term tachycardia. The QRS complex is significantly or has a time limit > 0.14 seconds. With the further development of cardiac electrophysiology research, there have been some new understandings of the mechanism of pre-contraction, but so far, no theory has given a full explanation. According to recent literature reports, there are mainly the following theories: 1 fold back to excitement. 2 ectopic rhythm points increase self-discipline. 3 trigger the activity. 4 parallel heart rhythm.

Cause

Premature ventricular contraction:

1 QRS wave appearing in advance, without P wave before it.

Before the 2nd stage, the QRS wave was widened (elderly > 0.12s, infant > 0.10s). The subsequent T wave direction was opposite. If the pace point is adjacent to the atrioventricular bundle, the QRS wave is close to normal.

The 3 compensation interval is complete.

In the same lead of the electrocardiogram, the pre-systolic contraction morphology is different, and the inter-trial interval is different, which is the polymorphic pre-contraction. After each interval of sinus beats, a pre-contraction is called the second law. After every 2 sinus fluctuations, a pre-contraction is triad and so on. The fourth and fifth pre-contraction contraction is 5 times per minute. The above is called pre-systolic contraction, and 5 or less is sporadic. With the further development of cardiac electrophysiology research, there have been some new understandings of the mechanism of pre-contraction, but so far, no theory has given a full explanation. According to recent literature reports, there are mainly the following theories:

a. Reentry is excited.

b. The ectopic rhythm point is increased in self-discipline.

c. Trigger the activity.

d. Parallel heart rhythm.

an examination

Related inspection

Electrocardiogram blood routine

Most patients have no obvious symptoms. Older children can have heart palpitations, discomfort in the anterior region, irregular heartbeat or chest impact on the heart, sudden sinking or pause, and the symptoms of premature contraction in heart disease patients are more obvious. Cardiac auscultation found a long pause after two close heartbeats, consistent with the pulse pause. The first heart sound of the pre-contraction contraction was mostly enhanced, and the second heart sound was weakened.

Complications: Generally, no complications, such as palpitations, are more obvious.

Diagnosis: The diagnosis of premature contraction mainly depends on electrocardiogram examination, and ventricular premature contraction is more common in healthy children. Only ventricular premature contraction, not heart disease, how to assess the clinical significance of ventricular premature contraction, should understand whether the child with accompanying symptoms, such as palpitation, dizziness or syncope, and whether there is heart disease, need to carry out the necessary an examination.

Differential diagnosis

Identification points for benign premature contraction and pathological premature contraction:

(1) Pathological pre-contraction (mechanic pre-contraction):

1 There are many basic diseases such as congenital or acquired heart disease, or pathological conditions such as metabolic disorders and drug poisoning.

2 joint or recurrent contraction.

3 multi-source or polymorphic pre-contraction.

4 showed a pre-contraction contraction of parallel heart rhythm.

The 5-ventricular premature contraction QRS complex significantly increased by >0.14 to 0.16 s.

6 each type of contraction coexisted before the period.

The sinus beat T wave changed after the 7th stage contraction.

8R-on-T type pre-contraction.

9 contraction before the frequency.

10 The number of pre-contraction increases or the exercise load test is positive.

Electrocardiogram has signs of myocardial damage, such as ST segment, T wave changes. Premature contractions associated with other arrhythmias such as tachycardia, bradycardia, conduction block, or prolonged QT interval.

(2) Benign pre-contraction (functional pre-contraction, also known as simple pre-contraction):

1 The history of non-organic heart disease was found by chance.

2 Clinically, there is no obvious symptom activity, and the heart is not restricted, and there is no organic heart murmur.

Before the 3rd stage, the contraction increased at night or at rest, and the number of contractions decreased or disappeared before the heart rate increased.

Before the 4th stage, the contraction was monogenic. There was no R-on-T phenomenon in the interval, no short ventricular tachycardia, no QT interval extension and ST segment T wave change, no conduction block and other electrocardiogram. abnormal.

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