Accelerated ventricular spontaneous rhythm
Introduction
Introduction to accelerated ventricular autonomic rhythm Accelerated ventricular arrhythmia (AIVR), also known as accelerated ventricular escape rhythm, non-paroxysmal ventricular tachycardia, accelerated ventricular self-pulsation rhythm, accelerated ventricular autonomy rhythm, ventricular autonomy Sexual tachycardia and so on. basic knowledge Sickness ratio: 0.01%-0.02% Susceptible people: no specific population Mode of infection: non-infectious Complications: paroxysmal ventricular tachycardia
Cause
Accelerated ventricular autonomic rhythm
(1) Causes of the disease
The most common patients with acute myocardial infarction may have repeated episodes in the acute phase. It is a common arrhythmia within 24 hours of acute myocardial infarction. It is more common in inferior myocardial infarction, and often occurs in the slow heart rate of sinus arrhythmia. Reported, in the anterior and inferior wall infarction is also common, in addition, accelerated ventricular arrhythmia is also the most common arrhythmia in acute myocardial infarction reperfusion, the incidence of revascularization after thrombolysis or PTCA treatment is 20.8 %, other causes are digitalis overdose, myocarditis, hyperkalemia, surgery (especially after cardiac surgery), complete atrioventricular block, ventricular escape, after application of isoproterenol, etc. The cause of quality is also occasionally seen in normal people.
(two) pathogenesis
Most people believe that its mechanism is the increased self-discipline of Purkinje fibers, with or without sinus node pacing.
The relationship between accelerated ventricular autonomic rhythm and pathological paroxysmal persistent ventricular tachycardia: accelerated ventricular arrhythmia is usually short-lived, prognosis is good, rarely develops into ventricular fibrillation, is a benign arrhythmia However, in recent years, patients with acute myocardial infarction accompanied by accelerated ventricular arrhythmia have a pathogenic paroxysmal persistent ventricular tachycardia with a prevalence of 43%, which can accelerate accelerated ventricular arrhythmia. Heart rate is divided into two types: 1 patients with ventricular rate of 60 ~ 75 times / min, rarely pathological paroxysmal persistent ventricular tachycardia; 2 ventricular rate of 75 ~ 100 times / min, prone to pathology Sexual paroxysmal persistent ventricular tachycardia.
Prevention
Accelerated ventricular autonomic heart rhythm prevention
Accelerated ventricular autonomic rhythm has little effect on hemodynamics, so it is a fundamental measure to prevent this type of arrhythmia by treating and preventing its primary disease.
Complication
Accelerated ventricular arrhythmia complications Complications paroxysmal ventricular tachycardia
Rapid accelerated ventricular autonomous rhythm is prone to pathological paroxysmal persistent ventricular tachycardia.
Symptom
Accelerated ventricular autonomous rhythm symptoms Common symptoms Tachycardia
Symptom
Accelerated ventricular autonomic rhythm is called tachycardia, but its frequency is not very fast, so it has no obvious effect on hemodynamics. Therefore, most patients have no obvious symptoms. The main symptoms and signs of patients are mostly primary. Symptoms and signs of illness.
2. Signs
The physical examination of accelerated ventricular autonomous rhythm has the following characteristics:
(1) Heart rate characteristics: heart rate is generally 55 to 110 times / min, compared with rules, mostly 60 to 80 times / min, rarely more than 100 times / min.
(2) The characteristics of the first heart sound: Because the strength of the first heart sound is related to the position of the atrioventricular valve at the beginning of the ventricular systole, this position is related to the length of the PR interval, and the position of the atrioventricular valve is relatively long during the PR interval. The first heart sound is weakened when closed. If the PR interval is shortened, the atrioventricular valve position is lower, the first heart sound is enhanced, and the accelerated ventricular arrhythmia patient has atrioventricular dislocation, and the P wave is not related to the R wave. The distance between the two can be different, so the strength of the first heart sound can be different at the time of auscultation.
(3) Jugular cannon wave: Accelerated ventricular arrhythmia due to atrioventricular dislocation, right atrial contraction when the tricuspid valve is closed, so the right atrial pressure is increased, the jugular vein can appear gun waves.
(4) Sometimes you can hear the systolic horse.
(5) The first heart sound and the third heart sound often have split sounds.
(6) No response to carotid sinus massage: accelerated ventricular autonomic rhythm will not be terminated by it.
(7) There are many short-term attacks and self-terminates at the time of attack.
Examine
Accelerated ventricular autonomic heart rate examination
Mainly rely on ECG examination;
1. Typical ECG features
(1) QRS complex malformation: the time limit is 0.12 s, and there is no relevant P wave before it.
(2) ventricular rate of 60 ~ 110 times / min: the general duration is shorter, often less than 30 cardiac cycles, the onset of start and stop is slow.
(3) Because its frequency is close to the sinus frequency: it is prone to atrioventricular dislocation, ventricular capture or ventricular fusion.
2. Detailed description of a typical ECG
(1) Accelerated ventricular autonomic rhythm can be divided into two categories based on the presence or absence of sinus-compartment competition:
1 Accelerated ventricular autonomic rhythm without sinus-chamber competition: seen in sinus arrest, atrial rest, so no sinus P wave, or ventricular autonomic rhythm, its excitatory control through the atrioventricular junction area, causing Retrograde P-wave, this P-wave mostly overlaps in the QRS wave can not be seen, in a few cases after the QRS wave, retrograde impulse can be transmitted to the sinus node, causing sinus rhythm reforming.
2 Accelerated ventricular autonomic rhythm with sinus-chamber competition: It refers to the intermittent interfering atrioventricular dislocation between sinus rhythm and accelerated ventricular autonomic rhythm, which is the phenomenon of sinus-chamber competition. The following two situations:
A. When both sinus rhythm and accelerated ventricular arrhythmia coexist: if the heart rhythms of the two are similar (only a few times per minute, mostly about 5 times/min), when accelerating ventricular autonomous rhythm When the frequency is faster than the sinus frequency, the ventricle is controlled by the ectopic pacemaker, and the atrium is controlled by the sinus node, forming an isometric (equal frequency) interfering atrioventricular dislocation, and the interference sites of the two are at the chamber. Area, when the sinus frequency is faster than the frequency of accelerated ventricular arrhythmia, it is easy to be captured by the sinus rhythm, and the ventricle captured at this time can be completely captured (QRS wave shape is sinus beat) It can also be incompletely captured (QRS wave morphology is ventricular fusion wave). Since sinus rhythm is slightly faster than ventricular rhythm, ventricular ectopic activation is suppressed and sinus rhythm is restored, but when sinus rhythm is excited Slower than ventricular ectopic agitation, atrioventricular interference occurs, and the atrioventricular septum forms an accelerated ventricular autonomic rhythm. These two rhythms can be seen competing on the electrocardiogram of continuous tracing.
B. Sinus rhythm alternates with accelerated ventricular autonomic rhythm.
(2) QRS complex frequency comparison rules: but it is not very fixed. The change per minute rarely exceeds 10 heartbeats, and the sinus frequency is rarely more than 5 times per minute. Therefore, if you do not have a surface ECG, Dynamic electrocardiography is easy to miss.
(3) The first heartbeat of accelerated ventricular arrhythmia often occurs in the late diastole: more in the slow phase of sinus arrhythmia, and the interval between the previous sinus beat is longer, and in the fast phase When the sinus rhythm is restored, the accelerated ventricular autonomic rhythm often forms a ventricular fusion wave with the sinus heartbeat at the beginning and the end, and sometimes several or more different degrees of ventricular fusion waves may appear.
(4) There is no fixed relationship between P wave and QRS wave: P wave often overlaps on malformed QRS-T wave.
(5) The origin of ectopic activation of accelerated ventricular arrhythmia is mostly at the proximal or distal end of the conduction bundle, so the deformed QRS waves are mostly bundle-blocking.
(6) Overspeed pacing can only inhibit and not terminate accelerated ventricular autonomous rhythm.
3. Special types of accelerated ventricular autonomous heart rhythm ECG
(1) Sustained accelerated ventricular autonomous rhythm is rare: seizures can last for several hours, several days, and individual years can reach several years (9 years).
(2) Over-speed accelerated ventricular autonomous rhythm: also known as ventricular pre-systolic accelerated ventricular autonomous rhythm, often starting with ventricular premature contraction or ventricular fusion wave, frequency is 90 ~ 100 times / min, Exceeding the sinus rhythm for 30 times/min, the basic sinus rhythm may not be slow, and there may be more ventricular capture and intermittent ventricular fusion waves, but there are no consecutive ventricular fusion waves. The ventricular rate is more rapid and uneven. This type of ventricular autonomic rhythm suggests that the heart has some pathological changes.
(3) Irregular accelerated ventricular autonomous rhythm: the rhythm is obviously irregular, and there is no regularity. The attack may start at any position of the RR interval of the dominant heart rhythm, or may be triggered by premature beats, or accelerated. At the beginning of the form of escape, the QRS wave is a bundle-blocking type, which can be seen in patients with no structural heart disease, and the prognosis is good (Figure 5).
(4) Accelerated ventricular autonomic rhythm and pathological paroxysmal ventricular tachycardia alternately appear: in patients with acute myocardial infarction, the incidence rate is different, the literature reports 42% to 83%, Beijing Fuwai Hospital report It is 10%. <
(5) Third degree atrioventricular block with accelerated ventricular arrhythmia:
(6) Escape-type accelerated ventricular autonomous rhythm: often begins with a ventricular pacing after a long interval, the ventricular rate is 50-84 beats/min, with an average of 62.2 beats/min, and the ventricular rate is slow. Rules, may be associated with ventricular premature contraction, third degree atrioventricular block.
(7) Mixed type: ventricular pre-systolic type and typical or escape-type accelerated ventricular autonomous rhythm.
(8) Accelerated ventricular autonomous rhythm with efferent block: rare.
Diagnosis
Accelerated ventricular autonomic heart rhythm diagnosis
According to clinical symptoms, physical signs and ECG features can make a correct diagnosis.
Differential diagnosis
1. Identification with parallel rhythm ventricular tachycardia
(1) There is afferent block in the ectopic pacemaker of parallel rhythm ventricular tachycardia, so the dominant sinus impulse can not be transmitted to the parallel arrhythmia pacemaker, so parallel rhythm ventricular tachycardia The cardiac cycle is not reorganized, and there is no protective afferent block around the ectopic pacemaker of accelerated ventricular arrhythmia, so when sinus rhythm occurs in the ventricular capture, the ectopic pacemaker The rhythm cycle that is emitted is reformed, that is, the captured sinusoidal ORS wave begins to restart according to the cycle of the ectopic rhythm itself.
(2) The ectopic beat of the parallel rhythm ventricular tachycardia can begin at any period of the cardiac cycle (except for the refractory period), and the long interval of the ectopic beat is an integer multiple of the short interval, and the accelerating chamber The first heartbeat of sexual autonomic rhythm occurs in the late diastolic phase, and there is no integral multiple of the long interval between ectopic beats.
2. Identification of intermittent left bundle branch block
Intermittent left bundle branch block can be short-radar QRS wave, but has normal P wave, and has a fixed PR interval with QRS wave, no atrioventricular separation, and accelerated ventricular arrhythmia The QRS wave is independent of the P wave and has a separation of the atrioventricular compartment.
3. Identification with pre-excitation syndrome
The QRS wave of pre-excitation syndrome has a fixed relationship with the P wave. The QRS wave has a delta wave at the beginning, and the accelerated ventricular autonomic rhythm does not have these two characteristics, so the identification is not difficult.
4. Identification of pathological paroxysmal ventricular tachycardia
(1) Pathological paroxysmal ventricular tachycardia (PPVT) starts and stops suddenly: the first QRS wave occurs in advance, and there is a complete compensatory interval at the termination, and accelerated ventricular autonomic rhythm (AIVR) For gradual onset, slow termination, the first QRS wave at the onset begins in the late diastole, and there is no complete compensatory interval at the termination.
(2) Frequency: PPVT is 150-250 times/min: 110-150 times/min, AIVR frequency is 60-110 times/min, and most are 70-80 times/min.
(3) ventricular fusion wave: PPVT is rare, AIVR is more common.
(4) The duration of PPVT episodes is longer: there is ventricular premature contraction in the intermittent episode; while the duration of AIVR episodes is short, only 3 to 30 heartbeats per episode, and there is no ventricular premature contraction during the episode.
(5) PPVT has a great influence on hemodynamics: it can cause blood pressure lowering or A-S syndrome, the prognosis is serious, and immediate treatment is needed; while AIVR does not cause hemodynamic changes, the prognosis is good, no special circumstances can be needed without treatment .
