idiopathic ventricular fibrillation
Introduction
Introduction to idiopathic ventricular fibrillation Idiopathic ventricular fibrillation (IVF), also known as primary electrical dysfunction (arrhythmic death with outdifiable heart disease), arrhythmia sudden death syndrome (suddenarrhythmicdeathsyndrome), etc. Causes of ventricular fibrillation, that is, ventricular fibrillation, sudden death, and survivors, after detailed invasive and non-invasive examinations (including autopsy), still cannot determine the clinical or functional clinical cause of the malignant arrhythmia . If such patients have found a cause of coronary heart disease, cardiomyopathy, etc. during the follow-up period, the original diagnosis should be changed. basic knowledge The proportion of illness: 0.005% Susceptible people: no specific population Mode of infection: non-infectious Complications: arrhythmia, syncope, A-S syndrome
Cause
Idiopathic ventricular fibrillation
(1) Causes of the disease
Most of the patients are young and middle-aged healthy people. The clinical manifestations of no previous heart disease, after extensive examination, are still not sure of the cause.
(two) pathogenesis
At present, it is unclear that the current research focus on this disease focuses on M-layer cardiomyocytes (M cells) and repolarization abnormalities. It is believed that epicardial and M-layer cardiomyocytes can sometimes be expressed as all or none of the repolar forms. The plateau period (2 phase) of the action potential is suppressed or disappeared, and the 3-phase rapid repolarization wave appears in advance. This "early repolarization" can shorten the action potential time course by 40% to 70%, causing the ST segment elevation of the corresponding part. High, the electrical heterogeneity between the plateau loss zone and the normal zone of the action potential, the difference and dispersion of repolarization between ventricular myocytes in different regions, leading to the occurrence of reentry ventricular arrhythmia, multi-site indoor Micro-reentry can cause ventricular fibrillation. It has also been observed that idiopathic J waves (small repolarization waves following the QRS wave) are associated with ventricular fibrillation, but so far there is no correlation between molecular biology and Related ion channel studies report that they help identify abnormalities in ion channel protein or ion channel transmembrane transport, which is likely to be the underlying cause of the disease.
Prevention
Idiopathic ventricular fibrillation prevention
Prevention includes two aspects: 1 Phase 1 prevention: prevention of ventricular flutter and tremor in patients with risk factors. 2 Phase II Prevention: Prevention of recurrence of ventricular flutter and tremor in survivors of ventricular flutter and tremor.
Complication
Idiopathic ventricular fibrillation complications Complications arrhythmia syncope A-S syndrome
Ventricular fibrillation is the most serious arrhythmia, the heart has lost the function of bleeding, clinical convulsions, syncope, A-S syndrome, sudden cardiac death.
Symptom
Idiopathic ventricular fibrillation symptoms Common symptoms QT interval prolonged sudden death syncope arrhythmia convulsion ventricular tachycardia tachycardia loss of consciousness pupillary abnormalities
After ventricular flutter and tremors, the ventricles lose their regular contractile activity. The result is loss of consciousness, convulsions, and cessation of breathing. If ventricular flutter and tremors are not terminated in time, the result is death.
Usually ventricular flutter and tremors occur suddenly, without aura symptoms.
Physical examination revealed loss of consciousness, inability to smell heart sounds, inability to converge on the pulse, blood pressure not measured, and cyanosis and dilated pupils.
Examine
Examination of idiopathic ventricular fibrillation
Mainly rely on ECG diagnosis.
Typical ECG characteristics of ventricular fibrillation: The QRS-T wave group of each lead disappears completely, and the tremor wave (f wave) with different shapes and different sizes and uneven spacing is 250-500 times/min. There are no wires between the chattering waves.
Diagnosis
Diagnosis and diagnosis of idiopathic ventricular fibrillation
diagnosis
Most of the diagnosis of idiopathic ventricular fibrillation is made by retrospective diagnosis of survivors of syncope or sudden death caused by ventricular fibrillation. The diagnosis requires the following two points.
1. Diagnosis of ventricular fibrillation
Must be confirmed by electrocardiographic recording of ventricular fibrillation, which may be primary ventricular fibrillation, or initial polymorphic ventricular tachycardia or cardiac arrest, and then develop into ventricular fibrillation, with There is syncope or sudden death.
2. Diagnosis of "idiopathic"
The diagnosis of idiopathic ventricular fibrillation must be preceded by other diseases before diagnosis can be made. The following aspects should be examined.
(1) A detailed review of clinical history: whether there is an application history of antiarrhythmic drugs or cardiovascular active drugs.
(2) Electrocardiogram: such as conventional electrocardiogram, 24h dynamic electrocardiogram, exercise load electrocardiogram and other examinations.
(3) blood biochemical examination: serum myocardial enzymes, blood sugar, electrolytes and other tests as well as blood, urine routine, nuclear thyroid function determination.
(4) Echocardiography, routine electrophysiological examination (especially whether programmed stimulation can induce ventricular tachycardia, ventricular fibrillation is helpful for diagnosis) and ventricular late potential examination.
(5) Coronary angiography: If the medical history is normal, the above several tests are normal, and other causes of ventricular fibrillation can be ruled out, then idiopathic ventricular fibrillation can be diagnosed, but the diagnosis of idiopathic ventricular fibrillation does not indicate the patient's There is no organic or functional abnormality in the heart, that is, when some abnormalities in the heart exist, it may not be the cause of ventricular fibrillation. The diagnosis of idiopathic ventricular fibrillation can still be made. The following cardiac abnormalities can be Coexisting ventricular fibrillation: 1 mitral valve prolapse without valve leaf length, without obvious mitral regurgitation; 2Q-T interval prolongation; 3 without pre-excitation syndrome paroxysmal and chronic atrial fibrillation : 4 incomplete atrioventricular block; 5 hypertension without left ventricular hypertrophy and right bundle branch block.
Differential diagnosis
1. Need to differentiate from other polymorphic ventricular tachycardia
The following two points are helpful in the differential diagnosis: on the electrocardiogram before or just after the onset of ventricular tachycardia, if there is a prolongation of the QT interval and the presence of U waves, a relatively long intercostal interval, or a typical induction sequence. (long-short circumference), etc., support TDP; the clinical situation when 2 ventricular tachycardia occurs is helpful for differential diagnosis.
2. This type of arrhythmia should be differentiated from the symptoms of paroxysmal syncope and sudden death.
For example, it should be differentiated from intermittent-dependent TDP, pre-excitation syndrome with extreme atrial fibrillation, idiopathic ventricular fibrillation, Brugada syndrome, sick sinus syndrome and epilepsy, except for secondary QT interval prolongation.
