non-paroxysmal sinus tachycardia
Introduction
Introduction to non-paroxysmal sinus tachycardia Nonparoxysmalsinustachycardia (NPST), called idiopathic sinus tachycardia (IST), is a clinical syndrome that has not been clearly defined so far, when it is active or mentally stressed. The resting heart rate is over-accelerated, the sinus heart rate is >100 beats/min, and there are no other causes of tachycardia. basic knowledge The proportion of sickness: 0.5% - 0.6% Susceptible people: no special people Mode of infection: non-infectious Complications: arrhythmia cardiomyopathy
Cause
Non-paroxysmal sinus tachycardia
(1) Causes of the disease
1. Abnormal sinus node itself: It is believed that only on the basis of abnormalities in the sinus node itself, there may be an increase in autonomic abnormality, and normal sinus node will not have autonomic dysfunction.
2. Right ventricular tachycardia: Some people think that non-paroxysmal sinus tachycardia is not sinus rhythm, but is very close to the atrial tachycardia at the atrium of the sinus node, produced on the electrocardiogram The P wave morphology and the sinus P wave morphology can be very similar, but the electrophysiological examination method has not been able to distinguish the two.
(two) pathogenesis
Its pathogenesis is still unclear, and there are currently three different theories:
1. Autonomic mediated dysfunction of autonomic regulation: due to excessive sympathetic tone or low vagal tone, the heart rate cannot be normalized when the external environment changes. The results show that non-paroxysmal sinus heartbeat The over-speed is mainly related to the abnormal regulation of the sinus node rhythm by the autonomic nerve. A few have an abnormal heart rate abnormality in the sinus node. Sgarbossa et al analyzed the heart rate variability of patients with non-paroxysmal sinus tachycardia through 24h dynamic electrocardiogram. The level of heart rate variability is directly proportional to the vagal tone, and inversely proportional to the level of sympathetic tone. Compared with normal controls, the heart rate variability is significantly reduced, reflecting abnormal vagal tone abnormalities, supporting non-paroxysmal sinus cardiac motion. Overspeed is a view mediated by autonomic dysfunction.
2. Autonomic increase of sinus node: The study confirmed that the mechanism of non-paroxysmal sinus tachycardia is related to the abnormality of primary sinus node (only the sinus node itself is abnormal, it may have an abnormal increase in autonomy). Normal sinus node does not have autonomic dysfunction. It is characterized by an increase in intrinsic heart rate, a decrease in cardiac vagal reflex, and an increase in -adrenergic sensitivity.
3. Right ventricular tachycardia: Some people think that non-paroxysmal sinus tachycardia is not sinus rhythm, but originates from atrial tachycardia at the atrium close to the sinus node, in the electrocardiogram P wave The morphology is very similar to the sinus P wave morphology. It is currently considered that even in the narrow sense, even the ectopic atrial tachycardia, which is very close to the sinoatrial node, cannot be classified as non-paroxysmal sinus tachycardia. However, because At present, the use of intracardiac electrophysiological examination methods may not be able to distinguish non-paroxysmal sinus tachycardia from right atrial tachycardia. Therefore, it cannot be considered that in non-paroxysmal sinus tachycardia There may be some right ventricular tachycardia.
Prevention
Non-paroxysmal sinus tachycardia prevention
The cause of this disease is unclear. At present, there is no effective prevention method. Avoid mental stress in daily life; quit smoking and alcohol, reduce the predisposing factors of this disease; have regular living, proper diet, do not overwork; exercise properly to prevent colds.
Complication
Non-paroxysmal sinus tachycardia complications Complications, arrhythmia, cardiomyopathy
A small number of patients with advanced disease can cause arrhythmogenic cardiomyopathy and refractory heart failure due to long-term tachycardia.
Symptom
Non-paroxysmal sinus tachycardia symptoms common symptoms nervous dizziness hypotension dysmotility tachycardia edema
Non-paroxysmal sinus tachycardia is more common in young people, most of whom are 20 to 35 years old. When you visit a doctor's medical history, you can find that the initial age of the symptoms is lighter, and the young women account for about the total number of cases. 90%.
The degree of clinical symptoms may vary. Some have only a heart palpitations, while others show chronic long-term sustained tachycardia. The most common symptoms in the history are palpitations, followed by chest tightness, fatigue, dizziness, etc. Many patients present their spirits. Symptoms, symptoms and miscellaneous, and the severity of tachycardia is not consistent, some patients with intermittent symptoms, and some long-term persistence, the course of disease is 1 to 11 years, can be caused by taking beta blockers Blood pressure caused by syncope, exercise tolerance test showed mild exercise that caused excessive heart rate response. It was reported that a small number of patients with advanced disease may cause arrhythmogenic cardiomyopathy due to long-term tachycardia, refractory heart failure, etc. Acute pulmonary edema, heart failure, cardiogenic shock and other critical symptoms, in addition, due to long-term use of larger doses of -blockers and other drugs, there are corresponding adverse reactions, such as dizziness, limb weakness.
Sinus tachycardia is the most important clinical manifestation of this disease, mainly has the following characteristics:
1. The heart rate at rest or during minor activities is greater than 100 beats/min.
2.24h dynamic electrocardiogram showed that the average heart rate increased significantly, the heart rate increased abnormally in daytime, and the nighttime decreased relatively. The heart rate of some patients could be reduced to the normal range.
3. Short-term exercise (5min walking or treadmill exercise test) The heart rate has a disproportionate increase, and the average heart rate can reach 140 times/min.
4. The heart rate is relatively low in the lying position, which is 60-135 times/min; the heart rate is significantly increased when standing up, which is 90-160 times/min.
5. Tachycardia can be intermittent, persistent or persistent.
6. In patients with arrhythmogenic cardiomyopathy and heart failure, the heart rate is often increased to 160-220 times/min, which impairs heart function.
7. Poor response to treatment with beta blockers or calcium ion antagonists.
Examine
Non-paroxysmal sinus tachycardia
1. ECG examination:
(1) Heart rate > 100 beats / min.
(2) The P wave shape is sinus when the tachycardia is overspeed.
2. Electrophysiological examination: In theory, in the episode of tachycardia, the high-pitched right atrium or the pacing site close to the suspected pacemaker of the sinus node can determine the origin of the excitement, but because the sinus node is a Anatomical localization of non-specific diffuse structures, and there is no clear boundary between atrial tissue, and paroxysmal sinus tachycardia and ectopic right atrial tachycardia are very similar to external stimuli, so two The distinction is difficult.
Diagnosis
Diagnosis and diagnosis of non-paroxysmal sinus tachycardia
Diagnostic criteria
Most patients with this disease except sinus tachycardia, physical examination, echocardiography, X-ray cardiovascular system examination confirmed that the heart often has no other primary organic abnormalities, nor caused sinus tachycardia Hyperthyroidism, anemia and other diseases, and often no clear cause, a small number of patients with structural heart disease, but their heart rate changes have no significant relationship with heart disease, there are also reports of radiofrequency ablation for atrioventricular node reentry or After atrioventricular reentry tachycardia, some patients may have non-paroxysmal sinus tachycardia.
The diagnostic criteria have not been unified so far, and the following points can be used as diagnostic conditions:
1. The ventricular rate is >100 beats/min during rest or minor activities.
2. The eccentricity of the electrocardiogram P wave is sinus.
3. There are symptoms when tachycardia attacks.
4. Other causes that cause significant sinus tachycardia, such as heart failure, hyperthyroidism, anemia, etc., need to be excluded.
5. Determination of sinus node intrinsic heart rate with atropine or beta blocker to completely block the sinus node autonomic nerve, determine the innate sinus node heart rate, use different doses of isoproterenol, evaluate the impact on heart rate and Heart rate response after exercise, many non-paroxysmal sinus tachycardia patients with increased heart rate and abnormal increase in isoproterenol sensitivity, can help diagnose.
Differential diagnosis
1. Sinus tachycardia: The heart rate of normal sinus tachycardia is 100-150 beats/min, and the ventricular rate usually does not exceed 100 beats/min during rest or slight activity, which is good for -blocker therapy. In general, the cause of sinus tachycardia is easy to be clear.
2. Intraventricular reentry tachycardia: heart rate is 140 ~ 250 times / min, P' wave morphology is different from sinus P wave, may have timely atrial premature contraction induced or terminated episodes, program-controlled stimulation can induce and terminate attack.
3. sinus reentry tachycardia: heart rate is 100 ~ 140 times / min, mostly around 120 times / min, P' wave morphology and sinus P wave is the same or similar, bursting episodes suddenly, Short duration of attack, pre-atrial contraction can induce and terminate tachycardia, and programmed stimulation can induce and terminate its onset.
4. Autonomic atrial tachycardia: It is difficult to distinguish from non-paroxysmal sinus tachycardia, and the frequency of spontaneous atrial tachycardia is gradually increasing ("preheating" or "warming" phenomenon) After 3 to 5 cardiac cycles, the heart rate gradually increases and stabilizes at a certain level (fixed heart rate), gradually decelerates before termination, and there is a longer compensatory interval at the end, rather than paroxysmal sinus tachycardia in sympathetic excitation At the time, the heart rate gradually increased; when the vagus nerve was excited, the heart rate gradually decreased, and the dynamic electrocardiogram showed a rapid heart rate and a large change in day and night.
