paroxysmal ventricular tachycardia
Introduction
Introduction to paroxysmal ventricular tachycardia Cardiac tachycardia caused by ventricular ectopic activation, sudden onset and termination, frequency 150 ~ 250 / min, regular, called paroxysmal ventricular tachycardia, if sustained for more than 30 seconds is called continuous ventricular tachycardia speed. More common in severe structural heart disease, especially acute myocardial infarction, complicated with myocardial infarction of ventricular aneurysm or heart failure, in addition to cardiomyopathy, acute myocarditis, QT interval prolongation syndrome, electrolyte imbalance, hypokalemia, Digitalis, quinidine, expectorant, phenothiazine poisoning, hypothermic anesthesia, cardiac surgery, and cardiac catheterization are occasionally seen in patients with no structural heart disease. basic knowledge The proportion of illness: 7% Susceptible people: no special people Mode of infection: non-infectious Complications: coronary heart disease cardiomyopathy heart failure mitral valve prolapse syndrome senile valvular heart disease sudden death tachycardia cardiomyopathy heart failure
Cause
The cause of paroxysmal ventricular tachycardia
Coronary heart disease (30%):
Such as myocardial infarction, angina or painless myocardial ischemia. The detection rate of myocardial infarction in the CCU ward was 6% to 40%. The detection rate was affected by the course of myocardial infarction. For example, the detection rate was 71% at 2 to 12 hours after onset, and the detection rate was only 10% after 2 weeks. 15%, the detection rate accounted for 27% within 24 hours of onset, about 2/3 of the patients showed repeated episodes, the heart rate was 150-250 times/min during continuous attack, and the heart rate was 150-200 times/min. %, the incidence of ventricular fibrillation was 50% in patients with heart rate >200 beats/min, and the incidence of ventricular tachycardia in patients with extensive anterior wall myocardial infarction was 75%. Continuous ventricular tachycardia occurred within 1 year after acute myocardial infarction. The rate of overspeed is about 30%; in the next 15 years, the annual rate is basically maintained at 3% to 5%.
Primary cardiomyopathy (30%):
Such as dilated cardiomyopathy, hypertrophic cardiomyopathy and restrictive cardiomyopathy. The incidence of persistent ventricular tachycardia was 26.3%, and there were two mechanisms: 1 micro-reentry: due to myocardial lesions and fibrotic lesions, myocardial activation and reentry were small reentry, 2 bundles of reentry: about 1/3 of patients It is the ventricle's excitement that passes through the bundle of one side and passes through the His bundle to the atrium. On the way, it is transferred from the other side to the atrium by the bundle of the other, and the bundle branch-bundle is folded back. Sexual tachycardia is not a type of ventricular tachycardia. Patients with dilated cardiomyopathy induce a persistent monomorphic ventricular tachycardia with programmed stimulation, and induce polymorphic ventricular tachycardia. The speed of 81%, for patients with persistent ventricular tachycardia in this disease, with program stimulation, 50% of patients with persistent ventricular tachycardia, ventricular late potential positive accounted for about 30%.
Electrolyte disturbance (10%):
Acid-base balance disorders, such as hypokalemia or hypomagnesemia.
Other factors (20%):
Myocarditis caused by various causes. Mitral valve prolapse syndrome. Various organic heart disease hypertensive heart disease; valvular heart disease (such as rheumatic valvular heart disease, senile valvular heart disease); congenital heart disease. Adverse reactions of drugs such as antiarrhythmic drugs, chloroquine, digitalis and expectorants, sympathomimetic drug overdose, etc. A few are seen in non-organic heart disease for unknown reasons.
Prevention
Paroxysmal ventricular tachycardia prevention
The cause of the attack should be avoided. Causes include exercise, excessive fatigue, emotional agitation, pregnancy, alcohol or excessive smoking. At the same time, it should be noted that this disease can not be engaged in special occupations, such as driving, diving, etc., before the radical cure, so as to avoid accidents when sudden onset.
Complication
Paroxysmal ventricular tachycardia complications Complications, coronary heart disease, cardiomyopathy, heart failure, mitral valve prolapse syndrome, senile valvular heart disease, sudden cardiac death, cardiomyopathy, heart failure
This disease often occurs in a variety of patients with structural heart disease, the most common coronary heart disease, especially in patients with myocardial infarction, followed by cardiomyopathy, heart failure, mitral valve prolapse, valvular heart disease, etc., in some In cases, it can also occur in patients with no structural heart disease. In these patients with obvious structural heart disease, sudden cardiac death, Asper syndrome, tachycardia cardiomyopathy, heart failure can occur. Sudden death can occur if the complications are severe.
1. Sudden cardiac death: 80% to 90% of arrhythmia sudden cardiac death is caused by ventricular tachyarrhythmia. Large-scale clinical retrospective studies have shown that more than 10% of patients with sudden cardiac death outside the hospital have ventricular cardiac motility. Over-speed is characteristic, 65% to 85% in the emergency treatment of ventricular fibrillation, sudden cardiac death is the most serious complication of ventricular tachycardia.
2, A-S Syndrome: also known as acute cardiogenic cerebral hypoxia syndrome, refers to a temporary cerebral ischemia, acute and transient loss of consciousness caused by cerebral hypoxia, accompanied by convulsions, pale, In the syndrome of cyanosis, in patients with syncope undergoing clinical electrophysiological examination, rapid ventricular arrhythmia accounts for 20% of the cause of syncope.
3, tachycardia cardiomyopathy: long-term tachycardia can lead to cardiac histology and pathology similar to dilated cardiomyopathy, clinical manifestations of heart enlargement and decreased cardiac function, known as tachycardia Disease, some scholars speculate that the incidence of chronic tachycardia over 10% to 15% of the total time per day may develop into tachycardia, ventricular tachycardia, including short ventricular tachycardia, Repeated episodes of continuous ventricular tachycardia, torsade de pointive ventricular tachycardia, concurrent rhythm ventricular tachycardia and bidirectional ventricular tachycardia can cause tachycardia.
4, heart failure: ventricular tachycardia, including persistent or non-sustained ventricular tachycardia, can lead to congestive heart failure.
Symptom
Paroxysmal ventricular tachycardia symptoms common symptoms tachycardia palpitations, difficulty breathing, pale ventricular tremor, shortness, dizziness, chest tightness, sudden death, blood pressure drop
Sudden onset of ventricular tachycardia, patients with obvious flustered chest tightness, can occur on the basis of ventricular premature beats, when the heart rate > 200 beats / min or obvious organic heart disease may have angina, acute left heart failure, emergence Aspen syndrome, even drowning. Physical examination should pay attention to the heart rhythm can not be very regular, the heart sounds slightly strong and weak differences. Unlike supraventricular tachycardia, the vagal stimulation method has no effect on heart rate.
Examine
Paroxysmal ventricular tachycardia
ECG performance:
1, 3 or more consecutive ventricular ectopic beats.
2. The QRS complex is broad and deformed with a time limit of >0.12 seconds. The T wave is opposite to the main wave of the QRS complex.
3. If P wave can be found, the P wave frequency is slower than the QRS wave group, and there is no fixed relationship between the P wave and the QRS wave group.
4, sometimes supraventricular sexual excitement can be transmitted to the ventricle, causing an early normal QRS wave group, called the ventricle captured. If the ventricular ectopic agitation at the time of ventricular capture and the ventricle are excited almost simultaneously, a ventricular fusion wave is generated. The presence of ventricular capture and ventricular fusion waves is a strong evidence for the diagnosis of ventricular tachycardia.
5. The shape of the QRS wave is consistent with the shape of the early room when it is not attacked.
6. The bidirectional ventricular tachycardia appears as a broad deformity in the direction of the main wave of the QRS complex.
7. Parallel rhythm ventricular tachycardia exists in parallel with supraventricular rhythm and ventricular tachycardia. The ventricular rate is 70-140/min. The interval between two episodes is the shortest time for ventricular tachycardia. The integral multiple of the RR interval is not equal.
Diagnosis
Diagnosis and diagnosis of paroxysmal ventricular tachycardia
diagnosis
Can be used for electrocardiogram examination, if necessary, can check the Histogram and / or cardiac electrophysiological examination.
1, history, symptoms: sudden ventricular tachycardia, patients with obvious flustered chest tightness, can occur on the basis of ventricular premature beats, when the heart rate > 200 beats / min or obvious organic heart disease can have angina, Acute left heart failure, Assy syndrome, and even sudden death. A history of heart disease and a history of ventricular tachycardia have been helpful in diagnosis. Knowing the timing and frequency of seizures, the history of drug use in the near future, especially the history of antiarrhythmic drugs, cardiotonics, and diuretics can sometimes help to find the cause of ventricular tachycardia.
2, physical examination found: short-term ventricular tachycardia or continuous ventricular tachycardia without hemodynamic disorders, general vital signs are more stable, heart auscultation heart rate is fast and roughly regular, intermittent intermittent audible and premature beats. Patients with underlying heart disease or heart rate >200 beats/min may be associated with hemodynamic disorders such as decreased blood pressure, difficulty breathing, sweating, and cold limbs, indicating that the patient is in critical condition and needs urgent treatment.
3, auxiliary examination: ECG can be clearly diagnosed, can record more than 3 consecutive rapid malformation QRS wave, and P wave has nothing to do, sometimes visible ventricular capture and ventricular fusion wave. A 24-hour ambulatory electrocardiogram that is infrequent or has a short episode is helpful for diagnosis. Cardiac ultrasound can identify heart-based diseases.
Differential diagnosis
It should be differentiated from the pre-excitation syndrome or the supraventricular tachycardia with bundle branch block.
