Ventricular Flutter and Ventricular Fibrillation
Introduction
Introduction to ventricular flutter and ventricular fibrillation The duration of ventricular flutter is often very short and quickly turns into ventricular fibrillation, so ventricular flutter is a precursor to ventricular fibrillation. Ventricular flutter is a transitional type between ventricular tachycardia and ventricular fibrillation, or it can be followed by ventricular fibrillation or doping. basic knowledge The proportion of illness: 0.005%, the incidence of hypertension in the elderly can reach 2% Susceptible people: the elderly Mode of infection: non-infectious Complications: A-Syst Syndrome Sudden Death Syndrome
Cause
Ventricular flutter and the cause of ventricular fibrillation
Causes:
Myocardial hypoxia, ischemia, electrolyte imbalance, drug poisoning and physical and chemical factors can cause ventricular flutter and ventricular fibrillation, which are often caused by arrhythmia before dying. But it can also be seen that the heart disease is not very serious, or there is no obvious heart disease, or even the heart without organic disease according to the sudden onset of ventricular flutter or ventricular fibrillation leading to cardiac arrest, the common causes are as follows:
1. Coronary heart disease: especially in acute myocardial infarction, unstable angina pectoris, ventricular aneurysm, reperfusion after thrombolytic therapy in acute myocardial infarction, etc., acute myocardial infarction complicated with ventricular fibrillation, no hypotension before ventricular fibrillation , shock or heart failure can be called primary ventricular fibrillation, such as hypotension before ventricular fibrillation, shock or heart failure called secondary ventricular fibrillation, primary and subsequent occurrence during acute myocardial infarction hospitalization The incidence of ventricular fibrillation was 2.7% and 2.8%, respectively. 71% of primary ventricular fibrillation occurred within 24 hours after acute myocardial infarction, and the highest incidence occurred in the first hour after onset, in the following hours. Rapid decline within the body, no primary ventricular fibrillation occurred 48 hours after infarction, secondary ventricular fibrillation 41% occurred 2 weeks after the onset of myocardial infarction, primary ventricular fibrillation occurred in the anterior wall myocardial infarction, when acute myocardial infarction Combined with bradycardia, conduction block or re-infarction, will increase the incidence of ventricular fibrillation. The survival rate of primary ventricular fibrillation in acute phase of myocardial infarction is 57%. Secondary ventricular fibrillation Rate was 18%.
2. Conversion from other arrhythmias to ventricular fibrillation:
(1) Complete or high atrioventricular block.
(2) Long QT interval syndrome with torsades de pointes ventricular tachycardia: Brugada syndrome.
(3) QT interval normal polymorphic ventricular tachycardia and extremely short intertemporal polymorphic ventricular tachycardia.
(4) Also seen in pathological paroxysmal persistent ventricular tachycardia.
(5) Pre-excitation syndrome with atrial fibrillation: If the bypass refractory period is <270ms, rapid atrial activation can be transmitted by bypass 1:1, resulting in ventricular fibrillation.
(6) arrhythmogenic right ventricular dysplasia ventricular tachycardia.
3. Other heart diseases:
(1) Cardiomyopathy: including dilated cardiomyopathy, hypertrophic cardiomyopathy, etc., their incidence of ventricular tachycardia is high, and the number of sudden death cases in the persistent ventricular tachycardia group is 56%, 19%; In the non-sustained ventricular tachycardia group, 5.4% occurred in dilated cardiomyopathy, and electrocardiographic examination confirmed that ventricular fibrillation accounted for 66%.
(2) valvular disease: such as aortic stenosis and dysfunction with angina or cardiac insufficiency.
(3) Myocarditis, acute pulmonary embolism, some mitral valve prolapse syndrome, aortic aneurysm rupture, cardiac tamponade, heart rupture.
(4) Performance of other patients with severe heart disease or other diseases before dying.
4. The toxicity of various drugs: such as digitalis, quinidine, procainamide, expectorant, phenothiazine and other drug poisoning.
5. Electrolyte disorders: mainly hypokalemia, or occasionally when hyperkalemia is too high, severe acidosis.
6. Cardiac Surgery: Especially during the open heart surgery under the low temperature anesthesia block cycle, ventricular fibrillation, tracheal intubation, cardiac trauma, right heart catheter or left can often occur during deep hypothermic cardiopulmonary bypass. Cardiac catheters, mitral balloon dilatation catheter failures, etc. may also occur.
7. Electric shock or drowning: When 300 mA of direct current or 70-80 mA of alternating current passes through the heart during electric shock, it can cause ventricular fibrillation. Freshwater drowning often causes ventricular fibrillation.
8. Others: myocardial ischemia, hypoxia, cardiac hypertrophy, sympathetic excitation, metabolic acidosis, bradycardia, cerebrovascular accidents, etc. can promote the occurrence of ventricular fibrillation.
Pathogenesis:
There are two theories:
1. Increased ventricular muscle self-discipline, resulting in single or multiple rapid ectopic excitability in the ventricle.
2. Micro-reentry agonism: When myocardial ischemia, hypoxia, myocardial necrosis and severe bradycardia, the repolarization rate of myocardial cells is inconsistent with the length of refractory period, and the height is inconsistent, and one or more micro-returns in the ventricular muscle are formed. The transmission route through different sizes and directions is transmitted to all parts of the ventricle, so that the contraction and relaxation of the myocardial parts of each part are not consistent.
Prevention
Ventricular flutter and prevention of ventricular fibrillation
prevention:
Primary prevention: prevention of ventricular flutter and tremor in patients with risk factors.
Secondary prevention: prevention of recurrence of ventricular flutter and tremor in survivors of ventricular flutter and tremor.
1. Phase I prevention: The first step is risk assessment. The first is to use a relatively simple examination method to exclude patients with low risk. Epidemiological data is the most valuable method to distinguish low-risk and high-risk patients, such as the crown. The history of myocardial infarction in patients with heart disease is the most common cause of ventricular flutter and ventricular fibrillation. The risk of ventricular fibrillation and ventricular fibrillation should be assessed. The vulnerability of ventricular muscle depends on three interactions, namely: 1 residual myocardial ischemia; 2 left ventricular dysfunction; 3 ECG instability, the relationship between each factor is interdependent, the interaction between the three is two-way, change any one of them, can By changing the other two factors, the risk of these three aspects is found by different examination methods. Once the risk assessment is completed, the differentiated high-risk patients must receive further treatment, such as beta blockers, aspirin and interventional therapy. It must be emphasized that further treatment does not specifically target the prevention of ventricular flutter and tremor, but can reduce overall cardiac mortality.
2. Phase II prevention: 20% to 25% of patients with ventricular flutter and tremor can survive, and the clinical treatment of survivors is a complex process, including multi-faceted clinical assessment and management.
(1) Diagnostic measures:
1 First determine the nature and extent of heart disease.
2 Assessment of left ventricular function.
3 In the case of different drug treatments, arterial ECG and exercise tests were used to determine the type, frequency and reproducibility of spontaneous ventricular arrhythmias.
4 Under the medical treatment, the induction of ventricular arrhythmia was measured by electrophysiological examination.
(2) Treatment measures:
1 If possible, discontinue the drug, especially antiarrhythmic drugs.
2 correct metabolic and electrolyte disorders.
3 to assess the predisposing factors.
4 improve left ventricular function.
5 control myocardial ischemia.
6 assess the neuropsychiatric state.
7 systematic assessment of antiarrhythmic drugs (non-invasive and invasive examinations).
Complication
Ventricular flutter and complications of ventricular fibrillation Complications A-Syst Syndrome Sudden Death Syndrome
Ventricular flutter and ventricular fibrillation are the most serious arrhythmias, and the heart has lost its ability to bleed. Clinical convulsions, syncope, A-S syndrome, sudden cardiac death. Ventricular flutter and tremor are often mixed or appear, and their effects on blood circulation function are equivalent to ventricular arrest. If not rescued in time, the patient can die within a few minutes. It is common in a variety of serious diseases (poisoning, electric shock, acute myocardial infarction, etc.), and is often a heart rhythm disorder before the death of patients with heart disease and other diseases.
Symptom
Ventricular flutter and ventricular fibrillation symptoms common symptoms arrhythmia cerebral ischemic ventricular fibrillation threshold lowering ventricular flutter convulsions coma ventricular fibrillation loss of consciousness
Ventricular flutter and ventricular fibrillation can be persistent or paroxysmal, recurrent in a short period of time, lasting a few seconds to 1-2 minutes or longer.
At the time of ventricular fibrillation, there is no effective contraction of the ventricle, and there is little or no blood discharge from the heart. Cerebral ischemia can occur rapidly, which is manifested as A-S syndrome. The patient suddenly convulsions, often convulsions throughout the body, and the length of time is not First, up to several minutes, most occur within 10s after ventricular fibrillation, loss of consciousness, coma often occurs after 30s of ventricular fibrillation, with several slow sighs breathing, the breathing gradually becomes shallow and stops, which often occurs in the ventricle Within 20 to 30 seconds after the tremor, the complexion changed from pale to dark purple, heart sound, pulse, and blood pressure disappeared. Most of the pupil dilation occurred in ventricular fibrillation for 30 to 60 seconds.
Examine
Examination of ventricular flutter and ventricular fibrillation
Mainly rely on ECG diagnosis.
1. Typical ECG characteristics of ventricular flutter: continuous and regular, wide, deformed QRS wave, ie ventricular flutter wave, QRS wave has a long time limit, above 0.12s, QRS wave has upward and downward amplitude like sinusoidal curve Can not be separated from the T wave, there is no wire between the QRS waves, the QRS wave frequency is more than 180 ~ 250 times / min, sometimes as low as 150 times / min or up to 300 times / min, P wave disappears.
2. Typical ECG characteristics of ventricular fibrillation: The QRS-T wave group disappears completely, and the tremor wave (f wave) with different shapes, different sizes and extremely uneven spacing, with a frequency of 250-500 times/min, vibrates There are no wires between the waves, and ventricular fibrillation can be divided into the following types according to the characteristics of the electrocardiogram:
(1) According to the f-wave coarse subdivision type:
1 rough wave: f amplitude > 0.5mV, more common in early ventricular fibrillation, extracorporeal circulation, open heart surgery or open chest compression, myocardial contraction function is relatively good, myocardial tension, creep is relatively large and powerful, The heart is brighter in color, and this type uses a shock and defibrillation effect.
2 fine tremor wave: f amplitude <0.5mV, also known as powerless ventricular fibrillation, more common in pre-dying cases, f-wave slender and weak, poor heart tension, dark complexion, poor response to shock defibrillation.
(2) According to the frequency classification of f wave:
When the frequency of 1f wave is between 100 and 500 times/min: the prognosis is relatively good, and electric shock defibrillation may make the cardioversion of some cases successful.
2f wave frequency <100 times / min: that is, very slow tremor wave, the prognosis is bad, and more quickly turn into ventricular arrest.
When the ventricular flutter and ventricular fibrillation, the atrium is excited independently, but it is often difficult to recognize the P wave due to the presence of a large and deformed flutter or tremor wave.
Diagnosis
Diagnosis of ventricular flutter and ventricular fibrillation
diagnosis
According to the patient's clinical manifestations and electrocardiogram, the diagnosis can be confirmed. Ventricular flutter and tremor are arrhythmias that cause rapid death of the patient, and rarely stop by themselves. Therefore, diagnosis should be made as soon as possible so that patients can receive timely treatment.
Differential diagnosis
1. Need to be differentiated from other polymorphic ventricular tachycardia: The following two points are helpful for differential diagnosis: on the electrocardiogram before or just after the onset of ventricular tachycardia, if there is QT interval extension and U wave The presence of a relatively long inter-discipline interval, or a typical induction sequence (long-short circumference), supports TDP; the clinical situation at the onset of ventricular tachycardia is helpful for differential diagnosis.
2. This type of arrhythmia should be differentiated from paroxysmal syncope and sudden death: for example, intermittently dependent TDP, pre-excitation syndrome with extreme atrial fibrillation, idiopathic ventricular fibrillation, Brugada syndrome, and sick sinus syndrome Identification of epilepsy and other phases should be excluded except for the extension of secondary QT interval.
