Ventricular parallel rhythm and ventricular parallel tachycardia

Introduction to ventricular parallel rhythm and ventricular parallel rhythm tachycardia Ventricular parasystole accounts for 60% of parallel heart rhythm. Ventricular parasystoletachycardia is more common than other parallel rhythm tachycardia. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: heart failure cardiogenic shock

Ventricular parallel rhythm and ventricular parallel rhythm tachycardia

Organic heart disease (80%):

About 86%, the highest incidence rate is 50-70 years old, about 65% of patients are over 60 years old, with coronary heart disease myocardial infarction, hypertensive heart disease is the most common, more than 50% of patients have heart failure, acute myocardium Infarcted ventricular parallel rhythm accounted for 1.7%, more common within 24h of onset, can occur intermittently for several hours, the drug is easy to control, benign arrhythmia, parallel heart rhythm can also be seen in cardiomyopathy, pulmonary heart disease, rheumatic heart Disease, myocarditis, congenital heart disease, etc., ventricular parallel rhythm has a higher incidence of heart disease than supraventricular parallel rhythm with heart disease, atrial and parallel heart rhythm healthy people more.

Rare cause (2%):

Such as uremia, hypokalemia, amyloidosis, leukemia, scleroderma, subacute bacterial endocarditis, nephritis, etc., digitalis poisoning does not cause ventricular parallel rhythm.

Other causes (15%):

About 15% of parallel rhythms are seen in healthy people who have parallel rhythms after exercise or after smoking. It is reported that younger people with no structural heart disease have more rhythmic ventricular tachycardia, accounting for 74.5% (35. /47), excessive fatigue, emotional changes, insomnia, etc. are common causes, suggesting that the production of parallel rhythm ventricular tachycardia may be related to autonomic dysfunction or humoral factors. In clinical applications of cardiac implantable pacemakers, many pacemaker arrhythmias fall into the category of parallel heart rhythms.

Pediatric causes (3%):

Children with parallel heart rhythm without organic heart disease are mostly benign arrhythmia, and are not prone to ventricular parallel rhythm tachycardia. There are also reports of children aged 2 to 14 years old, acute viral myocarditis accounted for 65 %, acute nephritis and other diseases accounted for 12%, and unexplained cases accounted for 23%, mostly due to mental stress, excessive fatigue and so on.

Pathogenesis

The electrophysiological basis of parallel heart rhythm is that in a small area of the heart, due to various diseases, the cells are ischemia, hypoxia, degeneration, etc., causing membrane permeability to change, resulting in different degrees of membrane potential reduction, some of which are cells. Produces 3-phase block; some cells increase autonomy and release evoked ectopic pacemakers and produce four-phase block. The conduction tissue around the pacemaker has a combination of 3-phase and 4-phase block. During the period, when the normal conduction interval between them is quite narrow, a complete afferent protective effect is formed.

The ectopic pacemaker of the parallel heart rhythm regularly emits excitement. It has nothing to do with the excitatory stimulation of the previous heart rhythm, and has two characteristics: protective afferent block and efferent block:

1. Protective afferent block There is a protective block around the arrhythmia pacemaker. The external stimulus is blocked and cannot be transmitted, that is, there is a protective afferent block.

2. The evanescent block is a one-way block, and the ectopic beat of the parallel heart rhythm, although it is regularly distributed, does not cause the heart to depolarize every beat, which is the block. .

Ventricular parallel rhythm and ventricular parallel rhythm tachycardia prevention

Because ventricular parallel rhythm is common in patients with structural heart disease and can coexist with other arrhythmias, active treatment of primary heart disease is the key to preventing such arrhythmias.

Ventricular parallel rhythm and ventricular parallel rhythm tachycardia complications Complications heart failure cardiogenic shock

Complications such as heart failure and cardiogenic shock may occur.

Heart failure: sudden severe breathing difficulties: respiratory frequency often reaches 30-40 times per minute, forced sitting position, pale complexion, cyanosis, sweating, irritability, frequent coughing, coughing pink foamy sputum, extremely heavy due to brain Hypoxia causes confusion, and at the beginning of the onset, there may be an increase in blood pressure. If the condition is not relieved, blood pressure can continue to decline until shock.

Cardiogenic shock: 1. Severe basic heart disease manifestations. 2. Circulatory failure manifestations: persistent hypotension, oliguria, disturbance of consciousness, peripheral purpura, etc.; can also be combined with acute pulmonary edema. 3. Changes in hemodynamic parameters: arterial pressure <10.7KPA (80mmHg); central venous pressure is normal or high; cardiac output is extremely low.

Ventricular parallel rhythm and ventricular parallel rhythm tachycardia symptoms common symptoms tachycardia flustered chest heavy heart palpitations arrhythmia

Patients with concurrent rhythm are usually asymptomatic. Frequent patients with concurrent rhythm or concurrent rhythm tachycardia may have symptoms such as palpitations, palpitation, chest pressure, and often fatigue, overwork, emotional changes, excessive stress, Insomnia and other incentives, can be rested, calmed, removed incentives or taking general antiarrhythmic drugs, quickly controlled, with the symptoms and signs of the primary disease.

Ventricular parallel rhythm and ventricular parallel rhythm tachycardia

There may be laboratory changes related to the primary disease.

ECG features:

1. Parallel heart rhythm and some basic ECG performance of parallel rhythm tachycardia

That is, three diagnostic criteria for parallel heart rhythm:

(1) The inter-rational interval is not fixed: if the inter-temporal contraction of the ectopic period is not fixed, the length is different, and the difference is greater than 0.08 s (some people also suggest that it is greater than 0.11 s), and the parallel rhythm should be suspected.

(2) The pre-systolic interval is equal to the multiple of the length of the ectopic beat cycle of the parallel heart rhythm: that is, the relationship between the shortest ectopic beat interval and the longer ectopic beat interval is that the long interval is the shortest interval. The integer multiple relationship of the period, or all the ectopic beats have a greatest common divisor, and the shortest ectopic beat interval or the greatest common divisor is the ectopic period of the parallel heart rhythm, but when the ectopic beat is small, However, the interval between ectopic beats is very long, so the common law method is easy to make mistakes, because a number of different common divisors can be obtained, so it is difficult to measure the cardiac cycle of parallel heart rhythm, and the ectopic cycle directly measured is often The ectopic period (the greatest common divisor) calculated from the sinus rhythm is slightly longer than the middle, and the reason is unknown. Therefore, this criterion only makes sense if the shortest joint interval is significantly smaller than the length of the shortest ectopic period.

(3) Fusion wave: When the parallel heart rhythm and the excitement of the basic heart rhythm reach the heart at the same time, each part of the ventricle excites the ventricular fusion wave. When the fusion wave is found on the electrocardiogram, no other arrhythmia is found. Parallel heart rhythm, at this time, the ECG should be observed continuously for a long time to find parallel heart rhythm, but it is the most non-specific diagnostic criteria, its sensitivity is also low, the total occurrence rate is 45%, atrial parallelism The rate of heart rhythm is only 17%, and the highest rate of ventricular parallel rhythm is 52%. There are many reasons for fusion waves. It should be carefully identified. For example, the more the number of fusion waves appears, the more the accelerated escape rhythm should be considered first.

2. Ventricular parallel heart rhythm ECG features

(1) Typical ECG characteristics of ventricular parallel rhythm:

1 The interval between the ventricular ectopic beats is not fixed, most of them appear in the form of ventricular premature contraction, and in a few cases, they appear in the form of ventricular escape.

2 The time interval between any two adjacent ventricular ectopic beats is equal, or there is a multiple of each other, or there is a greatest common divisor relationship.

3 is prone to ventricular fusion waves.

4 frequency 30 ~ 60 times / min, more common in 30 ~ 40 times / min, > 60 times / min for ventricular parallel rhythm tachycardia.

(2) A detailed description of the typical electrocardiogram of ventricular parallel rhythm:

The ventricular premature contraction of 1-ventricular parallel rhythm: ectopic pulsation of ventricular parallel rhythm is called ventricular premature contraction, and its QRS wave morphology is the same, single-source, mostly in the middle and late diastole, in the sinus When the sexual rhythm is slow, it is easy to show insertion. When the ventricular premature contraction has no retrograde P-wave, the compensatory interval is complete. If there is retrograde P-, the compensatory interval is incomplete, suggesting that there is sinus rhythm weight. Integrity, but this phenomenon is rare. Sometimes alternating parallel rhythms and premature pulsating impulses from the same ectopic pacemaker can occur. For example, premature pulsation bipolar law lasts for a few seconds or more and then turns into Parallel heart rhythm, the former can have a fixed inter-law interval.

2 joint interval: Because the ventricular parallel rhythm has nothing to do with sinus rhythm, the parallel rhythm of ventricular premature contraction may vary from 0.08s, which may appear on the same ECG. A very short inter-disciplinary interval, a long inter-trial interval is usually easy to merge with a ventricular fusion wave, and its QRS wave shape is between the sinus QRS wave and the ventricular QRS wave.

3-ventricular parallel rhythm with afferent block and efferent block is the same as type and atrioventricular block, also divided into one degree, second degree type I and type II, third degree block and superconducting, different types, Different combinations of afferent and afferent blocks form a different combination. The typical ventricular parallel rhythm is actually the result of a combination of third-degree afferent block and second-degree type II block.

4 The frequency of ventricular pacemakers is usually slower than sinus rhythm, mostly 30 to 40 beats/min. When >60 beats/min, the ventricular ventricular autonomic acceleration is called ventricular parallel rhythm tachycardia: eg <30 Times/min means that there is an efferent block, and when the frequency is close to the sinus rhythm, it will appear in the form of parallel heart rhythm tachycardia.

5 Because most ventricular parallel rhythms can not be reversed to the atria, they do not affect the sinus rhythm, and the compensatory interval is complete; when the sinus rhythm is slowed down, it can be inserted into the ventricular premature contraction form: Ventricular parallel heart rhythm can be reversed to the atria, then atrial fusion waves can be formed; such as ventricular ventricular arrhythmia, reversal into the atria and invading the sinus node, the sinus node can be excited to reconstruct the rhythm, and the compensation interval is Incompleteness, when the period of ventricular parallel rhythm is longer than the sinus cycle and shorter than the subsequent compensatory interval, the ventricular parallel rhythm will control the ventricle twice in succession, the first pre-contraction form appears, the second time The escape form appears.

The ventricular ectopic beat of 6-ventricular parallel rhythm should be given a localization diagnosis according to the performance of its electrocardiogram.

3. ECG characteristics of ventricular parallel rhythm tachycardia

(1) 3 or more consecutive ventricular ectopic beats, QRS widened, deformed.

(2) tachycardia begins with a ventricular ectopic beat that varies from one to the other.

(3) The ectopic beat frequency is accelerated, mostly 60-150 beats/min.

(4) The shortest interphase/shortest ectopic beat cycle with a length <80%.

(5) The pause interval of ventricular parallel rhythm tachycardia is an integral multiple of the ventricular parallel rhythm tachycardia cycle.

4. Detailed description of typical electrocardiographic features of ventricular parallel rhythm tachycardia

(1) When the frequency of ventricular parallel rhythm is greater than 60 times/min, the diagnosis of ventricular parallel rhythm tachycardia can be diagnosed. The frequency is more than 60-150 beats/min, and the minority can reach 140-220 beats/min. Chung The standard is 70 to 140 times/min.

(2) ventricular parallel rhythm tachycardia scattered in a short burst of episodes, the ventricular ectopic beat interval is gradually shortened, followed by a sudden extension, it is a second degree I (Wen's type) efferent block, If the interval between ventricular ectopic beats is different, but there is an integer multiple relationship with each other, it is a second-degree type II efferent block or a high-emission block. The latter frequency is not fast and is easily missed. A very short ventricular ectopic beat can be diagnosed. When there is a 2:1 block, the heart rate can suddenly halve or double with the appearance and disappearance of the block.

(3) Parallel rhythm ventricular tachycardia is a manifestation of ventricular autonomy. When the autonomous pulse is 1:1 or 2:1, the ventricular tachycardia rhythm is regular. Parallel rhythm ventricular tachycardia with Venturi-type efferent block, also has its regularity, atypical parallel rhythm ventricular tachycardia can be expressed as abnormal rhythm or RR interval, so Parallel rhythm ventricular tachycardia rhythm can be divided into three types: 1 irregular type (83%), most common; 2 regular type (4.2%); 3 long and short RR interval alternating type (12.7%).

(4) Parallel rhythm ventricular tachycardia has different durations, can be repeated, interval is normal sinus rhythm, there is a group report, each line of parallel rhythm ventricular tachycardia duration is 0.90 ~ 120s, average (24.3±15.6)s, QRS waveforms were single-line, 81% were right bundle branch block type, 19% were left bundle branch block type, and QRS time limit was 0.11~0.14s, parallel rhythm The average tachycardia cycle was (406.8 ± 88.6) ms.

(5) Frequent ventricular premature contraction conforms to the rule of parallel heart rhythm. The QRS waveform is the same as that of ventricular tachycardia, and the ventricular fusion wave can be seen.

Diagnosis of ventricular parallel rhythm and ventricular parallel rhythm tachycardia

diagnosis

According to the clinical manifestations and changes in ECG, the diagnosis can be confirmed.

Differential diagnosis

1. When ventricular parallel rhythm tachycardia has no efferent block (measured 1:1), the frequency is fast and regular, and should be differentiated from pre-systolic ventricular tachycardia (frequency >120 times / min)

It mainly depends on whether there is intermittent occurrence of tachycardia. If there is an interval, this interval refers to the last ventricular QRS complex of each ventricular tachycardia and the first ventricular QRS of the next ventricular tachycardia. When the distance between the waves is exactly the same as the short multiple or the shortest ventricular ectopic beat interval or an integer multiple of the greatest common divisor, it can be diagnosed as ventricular parallel rhythm tachycardia.

2. Identification with accelerated ventricular autonomous rhythm (non-paroxysmal ventricular tachycardia with a frequency of 70-130 beats/min)

At this time, it is not possible to use the "multiple relationship" to identify, but to rely on the following characteristics to identify, the first ventricular ectopic beat of ventricular parallel rhythm tachycardia is a sudden advance ventricular premature contraction; The onset of ventricular autonomic heart rhythm usually begins with late ventricular premature contraction or ventricular fusion wave. The episode occurs more frequently when the basal heart rate is slow. There is no parallel rhythm basis before and after the attack. The ventricular rate is mostly 60-100. Times / min.

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