Ventricular escape and ventricular escape rhythm
Introduction
Introduction to ventricular escape and ventricular escape rhythm If the atrioventricular junction area is also affected by the same cause as the sinoatrial node, if the escape is not possible, the ventricular pacemaker will activate the ventricle to form a ventricularescape, 3 or 3 consecutive. The above ventricular escape, which constitutes a ventricular escape rhythm (ventricularescapearrhythm). basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: dizziness, syncope, shock, A-S syndrome, angina pectoris, heart failure
Cause
Ventricular escape and ventricular escape rhythm
(1) Causes of the disease
More common in patients with severe heart disease, such as coronary heart disease, acute myocardial infarction, myocarditis, digitalis poisoning, quinidine poisoning, electrolyte imbalance, hyperkalemia, drug poisoning, also seen in low temperature anesthesia, and other serious heart disease, but most The common cause is the high and complete atrioventricular block caused by bilateral bundle branch block. At this time, the ECG performance is also complicated. The atrium can be controlled by the sinus node, and can also be atrial flutter, atrial fibrillation. Control of atrial tachycardia.
(two) pathogenesis
Ventricular escape or ventricular escape rhythm can occur in the following situations:
1. In sinus arrest, sinus block or severe sinus bradycardia, and the atrioventricular junction area failed to issue escape in the junction area.
2. Patients with atrial fibrillation use digitalis, especially when used excessively, to inhibit the occurrence of escape in the atrioventricular junction, and ventricular escape.
3. Sometimes the impulse from the above fails to pass through the atrioventricular junction, resulting in ventricular escape due to occult conduction, which is seen in the unreported atrial premature contraction or atrial fibrillation long RR interval .
4. The ventricular escape rhythm without atrial agitation (ie atrial stillness) is often an arrhythmia before dying. In the sudden death period, the frequency of ventricular escape rhythm can be extremely unstable, often slowing down gradually. The tendency to develop into auscultation heart sound disappears, a electrocardiogram has a very slow ventricular escape rhythm composed of several to more than ten heart beats (per minute), QRS complex large deformity, time limit can be >0.18s, at this time For the slow and ineffective ventricular autonomic rhythm, that is, the electrocardiogram-mechanical separation phenomenon, sometimes the escape rhythm can be converted into ventricular tachycardia, ventricular flutter, ventricular fibrillation and the like.
Prevention
Ventricular escape and ventricular escape rhythm prevention
Ventricular escape and ventricular escape rhythm are a physiological compensatory mechanism. When they appear, they should actively search for the primary disease that causes ventricular escape and ventricular escape rhythm, identify the cause, and actively treat the original disease. The cause of the disease is a fundamental measure to prevent such arrhythmia.
Complication
Ventricular escape and ventricular escape rhythm complications Complications vertigo syncope shock A-S syndrome angina pectoris heart failure
Generally, ventricular escape rhythm has a great influence on hemodynamics, and may have serious complications such as dizziness, syncope, shock, and A-S syndrome, and may also induce angina pectoris and heart failure.
Symptom
Ventricular escape and ventricular escape rhythm symptoms common symptoms, weakness, dizziness, tachycardia, chest tightness, ventricular fibrillation shock
Because the frequency of ventricular escape rhythm is 20-40 times/min, the heart rate is slow, and the hemodynamics often changes, so chest tightness, dizziness, weakness and other symptoms may occur, because it may be associated with ventricular tachycardia. Ventricular flutter, ventricular fibrillation, cardiac arrest, it can occur shock, heart failure, A-S syndrome, especially in patients with sudden death, the cardiac output is zero, in addition, due to ventricular escape Heart rhythm is common in severe heart disease, so there are often various clinical manifestations of heart disease.
1. The QRS wave frequency of slow and wide deformity can be seen on the electrocardiogram is 30~40 times/min. The degree of QRS complex is related to the position of the pace point. For example, the pace point is above the atrioventricular fork, QRS The degree of wave width and malformation is lighter, and the ventricular rate is more than 40 times/min; if the pace point is below the atrioventricular bifurcation, the degree of QRS wave wide deformity is heavy, and the ventricular rate is often below 40 beats/min, more than 30 ~40 times / min.
2. Most of the ventricular escape cycles are regular, but a few are irregular.
3. In the ventricular escape rhythm, the atrium and the ventricle are independent and excited, forming a complete atrioventricular separation.
Examine
Examination of ventricular escape and ventricular escape rhythm
Mainly rely on ECG examination.
1. ECG characteristics of ventricular escape
(1) Typical ECG characteristics of ventricular escape:
1 A deformed QRS wave appears after a long interval: the time limit is 0.12 s, which is often similar to the bundle branch block pattern, and the T wave is opposite to the QRS main wave.
2QRS wavefront without sinus P wave: occasional ventricular escape pulse can reverse the atrium, resulting in retrograde P-wave, called atrial capture.
3-ventricular escape and sinus activation can form ventricular fusion waves.
The end of the 4-ventricular premature contraction is shorter than the dominant rhythm, and the end of the ventricular escape is longer than the dominant rhythm.
(2) A detailed description of the typical ECG of ventricular escape:
1 The ventricular ectopic pacemaker has a low self-discipline, so it appears that ventricular activation occurs after a long ventricular interval. The escape period is generally 1.5 to 2.4 s, and the escape cycles are basically the same.
Both ventricular escape are delayed: the shape and time of the QRS wave depends on the origin of the escape point. For example, if the pacemaker is located at the bundle branch and the proximal end of the branch, the pattern is similar to bundle branch block or branch block. The graph, such as the pacing point is located at the branch of the His bundle, the QRS complex is similar to the normal QRS complex, similar to the escape of the atrioventricular junction. The lower the position of the pacemaker, the more obvious the QRS complex is. Because it is caused by intraventricular conduction through the ventricles.
If there are 2 or more escape beat points in the heart chamber, there may be two or more types of QRS waves with different forms. This is a multi-source ventricular escape, which should be associated with a multi-source ventricular phase. The pre-contraction phase is identified, the former is delayed, and the latter is premature.
3 There is a secondary ST-T change: the ST segment is down and the T wave is inverted on the R-based lead; in the QS or S-wave-based lead, the ST segment is elevated and the T wave is erect.
4 fusion wave: When the sinus impulse and the pacing point of the ventricular escape reach the ventricle at the same time, each part of the ventricle excites the ventricular fusion wave, and the ventricular escape is reversible to the atria in a few cases, ie P-wave appears, because the reverse conduction speed of the junction area is slower than the pre-transmission, so the retrograde P-wave is always after the QRS wave. If there is a sinus P wave, the PR' interval is often <0.12s, indicating the sinus P-wave and The QRS of ventricular escape is irrelevant, and the two compartments in the atrioventricular junction interfere with each other to form a compartmental separation.
2. ECG characteristics of ventricular escape rhythm
(1) Typical ECG characteristics of ventricular escape rhythm:
1 consecutive 3 or more ventricular escape.
2 ventricular rate is mostly 30 ~ 40 times / min: most of the escape interval is regular, but a few are slightly irregular.
3QRS wave width deformity: time limit 0.12s.
(2) A detailed description of a typical ECG of ventricular escape rhythm:
The frequency of 1-ventricular escape rhythm: mostly 30 to 40 times / min, can also exceed 40 times / min, can also be less than 20 times / min, which is related to the pace point, such as the pace point in the atrioventricular Above the bundle bifurcation, the ventricular rate is faster, up to 40 ~ 50 times / min, when the pace point is below the atrioventricular bundle bifurcation, the ventricular rate is often below 40 times / min, mostly 30 ~ 40 times / min, In the sudden death period, the ventricular rate can be extremely unstable, and there is a tendency to gradually slow down, which can be 10-20 times/min, or less than 10 times/min.
The degree of 2QRS wave width malformation: related to the location of the pace point, the same as the QRS wave with ventricular escape delay.
3-ventricular escape rhythm: Most of the escape stroke cycle is regular, but there are also a few irregularities. Irregular escape stroke can be seen in multi-source ventricular escape rhythm, and can also be seen in single-source ventricular escape. Heart rhythm, before dying, the prolapse interval is often progressive, it can be seen that the ventricular escape rhythm begins to attack at a slower frequency, and then gradually accelerates until it becomes a rule. Some people call this phenomenon "Treppe phenomenon."
4-ventricular escape rhythm: the atrium and ventricle are independent and excited, forming a complete atrioventricular separation.
Occasionally, the 5-ventricular escape rhythm can be seen in the ventricular escape with agitation and retrograde to the atrium to form atrial capture.
In the 6-ventricular escape rhythm, the supraventricular impulse (sinus or atrial) can be transmitted down with the ventricular escape pulse and simultaneously a part of the myocardium, forming a ventricular fusion wave.
7 In severe heart disease: ventricular escape rhythm may be converted to ventricular tachycardia, ventricular flutter or ventricular fibrillation, cardiac arrest.
Diagnosis
Diagnosis of ventricular escape and ventricular escape rhythm
diagnosis
Diagnosis was based on clinical manifestations and ECG characteristics.
Differential diagnosis
1. The intersection area escape rhythm with indoor differential conduction and ventricular escape rhythm identification intersection area escape rhythm with indoor differential conduction ventricular rate is 40 ~ 60 times / min, QRS wave is mildly deformed, mostly Right bundle branch block pattern, time limit <0.11s, more ventricular fusion wave, ventricular escape rhythm, ventricular rate is 20 ~ 40 times / min, QRS wave wide deformity, mostly single-phase or two-phase, The time limit is >0.12s, and there may be a ventricular fusion wave.
2. Identification of ventricular escape rhythm and accelerated ventricular escape rhythm The former ventricular rate is 20 ~ 40 times / min, which is the passive rhythm of the atrioventricular junction; while the latter ventricular rate is 60 ~ 110 times / min, is the ventricle Active heart rhythm.
