Frequent atrial premature beats

Introduction Premature beats are also called pre-systolic and extra-systolic, referred to as premature beats. It is an early ectopic heart beat. According to the origin, it can be divided into four types: sinus, atrial, atrioventricular junction and ventricular. Occasionally or frequently, frequent (>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. Premature beats can be asymptomatic, and there can be a feeling of palpitations or heartbeat. Frequent premature beats can cause symptoms such as fatigue and dizziness due to decreased blood output. The original heart disease can induce or aggravate angina or heart failure. Auscultation can be found that the heart rhythm is irregular, and there is a long compensatory interval after the premature beat. The first heart sound of the premature beat is more enhanced, and the second heart sound is weakened or disappeared. When the premature beat is in the second or third joint, you can hear a long pause after every two or three heart beats. Premature beats are inserted between two regular heart beats, which can be expressed as three consecutive heart beats. Pulse palpation can be found in intermittent pulse.

Cause

Frequent atrial premature beats, seen in mitral valve disease, hyperthyroidism or coronary heart disease, especially multi-source, may be a prelude to atrial fibrillation. There are many reasons for premature beats. Some healthy people may have premature beats in their hearts, but they are more likely to occur in morbid hearts. Premature beats are very common, and it is inevitable that no one will happen in a lifetime.

In general, the younger the age, the rarer it is. The older you get, the more common it is. Its highest incidence is between 50 and 70 years old. About 5% of healthy people can have premature beats. Premature beats can occur, which can reduce the amount of heart beat. However, premature beats less than 6 times per minute have little effect on physical health (physiological). There are often some artificial incentives for healthy people to have premature beats, such as emotional excitement, full meal, overwork, upper respiratory tract infection, biliary system disease, electrolyte imbalance, and drug effects.

an examination

Related inspection

Dynamic electrocardiogram (Holter monitoring) ECG

Mainly by ECG diagnosis, ECG performance can have the following performance:

1. Characteristics of typical atrial premature contraction ECG:

(1) Shaped P' wave appearing in advance: The P' wave shape is different from the sinus P wave. The P' wave is usually not retrograde, but if it originates from the lower part of the atrium, its P' wave can be retrograde.

(2) The P'-R interval is greater than 0.12 s.

(3) The shape and time limit of the QRS complex are the same as the basic sinus rhythm.

(4) There is an incomplete compensation interval.

2. Description of typical ECG characteristics of pre-atrial contraction:

(1) P' wave: The P' wave of premature atrial contraction appears in advance, which can overlap the T wave of the previous sinus beat and the T wave, which can cause the T wave to blunt, notch or increase or decrease the amplitude. And so on. If it is earlier, the P' wave can overlap on the ST segment, or the R wave falls to the S wave region. ST segment, T wave, R wave drop to S wave region are atrial fibrillation, which easily lead to atrial fibrillation. The P' wave can be high-pointed, flat, bi-directional or inverted. There may be two or more P' wave patterns on the same lead, which is called multi-source atrial premature contraction.

(2) P'-R interval: The P'-R interval of atrial contraction is greater than 0.12 s. Its length depends on the degree of advancement of premature contraction and the conduction function of the atrioventricular junction. Atrial contraction occurs in the late stage of contraction. The P' wave occurs at the peak of the T wave to the end of the T wave. Because the compartmental junction area and the ventricle are in a relatively refractory period, it is prone to P'-R interphase interference prolongation, often exceeding 0.20 s, and often there is indoor differential conduction. Pre-atrial contraction occurs in the early stage of diastole, and the P' wave occurs at the end of the T wave to the end of the u wave. In addition, occasional P'-R interval prolongation and/or indoor differential conduction may occur. Usually, in the case of normal atrioventricular conduction function, pre-expansion and early diastolic atrial contraction, the P'-R interval is 0.12 to 0.20 s. Pre-systolic pre-systolic contraction, which occurs in the pre-atrial contraction between the J-point and the T-wave peak, cannot be transmitted because the atrioventricular junction area is in an absolute refractory period. However, a few atrial premature contractions fall in the first supernormal period, that is, in the middle segment of the ST segment, and are unexpectedly transmitted underground, which is called supernormal conduction; if not in the middle segment of the ST segment, but in other parts of the mid-systolic period Transmission is also a super-period conduction, that is, a void phenomenon. If the atrial premature contraction occurs earlier, because the atrioventricular junction area is in an absolute refractory period, the P' wave is not blocked by the QRS wave due to the block, which is the room that has not been transmitted (or blocked). Contraction before sexual sex.

(3) QRS-T wave: usually normal, QRS wave with wide deformity may appear after pre-atrial contraction in the following cases: 1 with indoor differential conduction; 2 with pre-excitation syndrome; 3 with There is bundle branch block.

(4) Compensation Intermittent: Usually it is an incomplete compensation compensation interval. The following three manifestations can also occur: 1 In a few cases, a complete compensatory interval occurs, which is due to the late atrial contraction, and the P' wave falls in the first 20% of the sinus cycle. At this time, the sinus node impulse has begun to be released, and the two interfere with the sinus junction, but the next sinus impulse is still issued on time, so a complete compensatory interval is formed; 2 the premature contraction is inserted, that is, An atrial premature contraction was inserted between the two sinus beats, without compensatory interval (PP'+P'-P=PP); 3 premature contraction occurred prematurely, and the P' wave fell at the beginning of the sinus cycle. 15% to 17%, can be introduced into the sinus node caused by sinus echo, which showed an early sinus P wave after atrial contraction on the electrocardiogram.

Differential diagnosis

Differential diagnosis:

First, atrial premature beats: P wave appeared in advance, the shape is different from the P wave of sinus rhythm, PR interval > 0.12 seconds. Most QRS complexes are the same as sinus rhythm, sometimes slightly widened or deformed, with ST segment and T wave corresponding changes, called indoor differential conduction, need to be differentiated from ventricular premature beats, the former QRS wave group can see P wave, The PR interval is >0.12 seconds, and the V1QRS wave group is mostly rsR. There was no QRS wave after the early malformation P wave, which was called atrial premature beat and did not turn down to block atrial premature beat.

Second, atrioventricular junction premature beats: QRS complexes appearing early, the morphology of which is the same as sinus or both indoor differential conduction. Retrograde P waves are sometimes seen before and after the QRS complex, with a PR interval shorter than 0.12 seconds or no P wave. The compensation interval can be incomplete or complete.

Third, ventricular premature beats: there are premature QRS complexes, their morphology is abnormal, most of the time 0.12 seconds, T wave and QRS wave group main wave opposite, ST segment shifts with T wave direction, there is no correlation before P wave, there is a complete compensatory interval. Ventricular premature beats can occur between two sinus beats, forming an insertional ventricular premature beat.

Fourth, multi-source premature beats: atrial or ventricular premature beats are sometimes produced by more than two pace points, the QR wave of P wave and ventricular premature beats in atrial premature beats in ECG have two or more different forms, and The pairing interval varies and is called multi-source premature beats. Frequent premature beats can occur in succession. If more than 3 times, it is called short-term tachycardia.

V. Parallel rhythm type premature beats: It is characterized by the fact that the pairing interval is not constant, but there is a fixed law between the premature beats. The longest prepulse beat interval is the integral multiple of the shortest premature beat interval, and often there is atrial or ventricular fusion wave. .

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