What Is Ventricular Tachyarrhythmia?

First, ^[1] ventricular premature contraction

Ventricular arrhythmia

Ventricular arrhythmia refers to arrhythmia that originates in the ventricle and is a common arrhythmia, including ventricular premature beats (preventricular), ventricular tachycardia (ventricular tachycardia), ventricular fibrillation (ventricular fibrillation), and so on. Ventricular tachycardia, especially those with organic heart disease, is usually an arrhythmia that can lead to severe consequences such as ventricular fibrillation and sudden death. It is necessary to make a clear diagnosis in time, determine the cause of VT, its causes, and its impact on prognosis and deal with it in a timely manner. The incidence of ventricular arrhythmias in the elderly population increases with age just like organic heart disease.

Ventricular Arrhythmia Common Causes and Characteristics of ECG

First, ^[1] ventricular premature contraction

1. Etiology: Common in patients with coronary heart disease, rheumatic heart disease and mitral valve prolapse.

2. ECG characteristics:

1) QRS complexes occur in advance. The time limit usually exceeds 0.12s, and the distortion is large. The directions of ST segment and T wave are opposite to the direction of QRS main wave. No P wave before it

2) The period between the pre-ventricular contraction and the sinus beat before it is constant

3) The complete compensatory interval, that is, the interval between the two sinus beats, including the ventricular premature contraction, is equal to the sum of the two sinus RRs.

4) ECG manifestations with ventricular parallel rhythm

Paroxysmal ventricular tachycardia

Cause:

1) Common in organic heart disease such as coronary heart disease, cardiomyopathy, myocarditis, myocardial infarction, etc.

2) Drug poisoning such as antiarrhythmic drugs, chloroquine, digitalis and antimony, sympathomimetic overdose, etc.

3) Hypokalemia or hypomagnesemia

4) Mechanical stimuli such as low temperature anesthesia, surgery and cardiac catheterization

5) Few are found in non-organic heart disease

2. ECG characteristics:

1) Three or more ventricular premature contractions appear continuously

2) The shape of the QRS complex is abnormal. The time limit exceeds 0.12s. The direction of the ST-T wave is opposite to the main wave of the QRS complex.

3) The ventricular rate is usually 100-250 times / min, the rhythm is regular, but it can also be slightly irregular

4) There is no fixed relationship between independent atrial activity and QRS complex, which leads to separation of atria and atria. Occasionally individual or all ventricular backfires capture atrium

5) Ventricular capture and ventricular fusion waves

Ventricular fusion wave, ventricular capture, all precardiac lead QRS complexes are isotropic, and the ECG manifestations indicate ventricular tachycardia

Third, ventricular fibrillation

Cause:

Commonly before death, acute myocardial infarction, severe hypokalemia, etc.

2. ECG characteristics:

Completely irregular wave, 150 500 times / minute

Classification and description of ventricular arrhythmia diseases

(1) Ventricular premature beats

The incidence of early age room is 70% -80%. The number of ventricular premature patients increased with age, but the complexity of ventricular premature patients did not increase correspondingly. The elderly with higher levels of ventricular early (Lown classification) had higher rates of ECG abnormalities. Often accompanied by myocardial hypertrophy, infarction and other abnormal manifestations. Ventricular premature beats have completely different clinical significance and prognosis under different circumstances, and are related to the presence or absence of organic heart disease, the type of heart disease, and cardiac function.

(B) Ventricular tachycardia (ventricular tachycardia)

Ventricular tachycardia (ventricular tachycardia), referred to as ventricular tachycardia, is common in AMI, ventricular aneurysm, heart failure, electrolyte disturbances, and drug poisoning. Tip torsional ventricular tachycardia is caused by multi-loop reentry or irregular reentry due to increased dispersion of ventricular repolarization. More common in low potassium, quinidine, amiodarone, tricyclic antidepressant poisoning.

(3) Ventricular flutter and ventricular fibrillation Ventricular flutter and ventricular fibrillation are common in ischemic heart disease. In addition, antiarrhythmic drugs, especially those that cause QT interval prolongation and tip twist, severe hypoxia, ischemia, pre-excitation syndrome combined with atrial fibrillation, extremely fast ventricular rate, electric shock, etc. Ventricular flutter and fibrillation are fatal arrhythmias.

Clinical manifestations of ventricular arrhythmias

1. Ventricular premature beats

Ventricular premature contractions often have no symptoms directly related to them; whether each patient has symptoms or the severity of the symptoms is not directly related to the frequency of premature contractions. Patients can feel palpitations, similar to the weightlessness of a rapid elevator lift or a strong heart beat after a compensatory break.

During auscultation, a longer pause followed the pre-ventricular contraction, and the second heart sound intensity of the pre-ventricular contraction weakened, and only the first heart sound was heard. Radial artery pulsation weakened or disappeared. Jugular veins show normal or huge a waves.

The characteristics of an electrocardiogram are as follows:

1. The QRS wave group that occurs in advance usually has a time limit of more than 0.12 seconds and is wide and deformed. The directions of the ST segment and the T wave are opposite to the direction of the QRS main wave.

2. The period between the preventricular contraction and the sinus beat preceding it (known as the pairing interval) is constant.

3 Ventricular premature contraction rarely reverses the atrium and excites the sinoatrial node in advance, so the impulsive rhythm of the sinoatrial node is not disturbed, and there is a complete compensatory intermittent after ventricular contraction, which includes The interval between the two sinus pulsations before and after is equal to the sum of the two sinus RR intervals. If the ventricular premature contraction happens to be inserted between two sinus beats, there is no pause after the premature ventricular contraction, which is called interstitial ventricular premature contraction.

4 Types of premature ventricular contractions Ventricular premature contractions can occur in isolation or regularly. The doublet law means that each sinus beat follows a preventricular contraction; the triplet law means one premenstrual contraction after every two normal beats; and so on. Two consecutive premature ventricular contractions are called pairwise premature ventricular contractions. Three or more consecutive pre-ventricular contractions are called ventricular tachycardia. In the same lead, those with the same pre-ventricular contraction form are unimorphic pre-ventricular contractions; those with different morphology are called polymorphic or multi-source pre-ventricular contractions.

5. Ventricular parasytole Ventricular ectopic pacemaker regularly issues impulses on its own and prevents sinus node impulses from invading. Its electrocardiogram manifests itself as: the pairing interval of ectopic ventricular beat and sinus beat is not constant; the long distance between two ectopic beats is an integral multiple of the shortest two ectopic beat intervals; when it is dominant The impulse of the heart rhythm (such as sinus rhythm) and the impulse of the ventricular ectopic pacing point reach the ventricle at the same time, and a ventricular fusion wave can be generated. Its shape is between the two QRS wave group shapes.

Ventricular tachycardia (ventricular tachycardia)

The clinical symptoms of ventricular tachycardia vary depending on the ventricular rate, duration, underlying heart disease and cardiac function at the time of the attack. Patients with non-sustained ventricular tachycardia (onset of spontaneous termination of less than 30 seconds) are usually asymptomatic (Figure 3-3-24). Persistent ventricular tachycardia (onset of more than 30 seconds, which requires medication or electrical cardioversion to terminate) is often accompanied by significant hemodynamic disorders and myocardial ischemia. Clinical symptoms include hypotension, oliguria, syncope, shortness of breath, and angina pectoris. On auscultation, the heart rhythm is slightly irregular, the first and second heart sounds are split, and the systolic blood pressure can change with the heartbeat. If complete atrioventricular separation occurs, the intensity of the first heart sound often changes, and a giant a wave appears intermittently in the jugular vein. When the ventricle beats back and continues to capture the atrium, the atria and ventricles contract almost simultaneously, and the jugular vein presents a regular and huge a wave.

Ventricular flutter and ventricular fibrillation

Clinical symptoms include loss of consciousness, convulsions, apnea, and even death, auscultation of heart sounds, impaired pulse, and undetectable blood pressure.

Primary ventricular fibrillation associated with acute myocardial infarction without pump failure or cardiogenic shock has a better prognosis, a higher rescue survival rate, and a lower relapse rate. In contrast, ventricular fibrillation, which is not associated with acute myocardial infarction, has a recurrence rate of 20% to 30% within one year.

For the treatment of ventricular flutter and fibrillation, please refer to Chapter 4 "Sudden Cardiac Arrest and Sudden Cardiac Death" in this chapter.

Ventricular arrhythmia treatment plan

Patients with premature ventricular disease should use lidocaine, propafenone, amiodarone and other drugs based on the etiology treatment to reduce the grade and number of premature ventricular disease to reduce the risk of sudden death. There is no need for antiarrhythmic medications. Symptomatic and life-threatening anti-arrhythmic drugs such as mexiletine and beta-blockers can be used to reduce symptoms rather than eliminate premature ventricular dysfunction. For the treatment of patients with ventricular tachycardia, in addition to the etiology (potassium supplementation and drug withdrawal), the intravenous injection of 25% magnesium sulfate is preferably 1-2g, which is followed by intravenous infusion of 1mg / min, and 12-48 / h. Isoproterenol was once the drug of choice (0.5mg / 500ml intravenous drip). Ventricular fibrillation is now rarely used due to excessive dosage. If the drug treatment is not effective, esophageal atrial pacing or historical endocardial pacing can be used. The beat rate is 100 / min, and it can control VT. Those with low blood pressure and fainting during ventricular tachycardia, should be immediately shocked by irregularities followed by intravenous drip of lidocaine. If there is no hemodynamic change during the onset, immediately inject lidocaine 50-75mg. After 2min, it is ineffective and then use 50mg, followed by 1-4mg / min. Lidocaine is ineffective and can be treated with procainamide, propafenone, amiodarone, bromobenzamine and other drugs.

Nursing measures for ventricular arrhythmia

(I) General Nursing

1. Take a break. Patients should have adequate rest and sleep when arrhythmia causes symptoms such as palpitations, chest tightness, dizziness, etc. Avoid lying on the left side during rest to prevent the heart from beating and aggravating discomfort in the left side.

2. Diet. Give foods rich in cellulose to prevent constipation; avoid full meals and intake of irritating foods such as coffee and strong tea.

(2) Observation of illness. Connect to an ECG monitor to continuously monitor changes in heart rate and heart rhythm, and detect danger signs early. Measure vital signs in time, measure pulse time for 1 minute, and listen to heart rate. When the patient has frequent multi-source pre-ventricular systole, RonT pre-ventricular systole, ventricular tachycardia, second-degree type II and third-degree atrioventricular block, inform the doctor in time and cooperate with the treatment. Monitor electrolyte changes, especially serum potassium.

(3) Rescue. Prepare rescue equipment with rescue equipment (such as defibrillators, electrocardiographs, ECG monitors, temporary pacemakers, etc.) and various antiarrhythmic drugs and other rescue drugs.

(D) medication. When using anti-arrhythmic drugs in nursing, closely observe the effects of the drugs and adverse reactions to prevent the occurrence of toxic and side effects.

(5) Nursing of interventional treatment. Introduce the patient to the purpose and method of interventional therapy such as cardiac catheter radiofrequency ablation or pacemaker placement to eliminate the patient's nervousness and enable the patient to actively cooperate with the treatment. And do the appropriate nursing interventional treatment. ^[2]