A normal human heart rhythm is controlled by impulses generated by the sinus node, so it is called sinus rhythm, in other words, normal heart rhythm, but of course, it is not good to have a sinus heart rate that always exceeds 100 beats per minute (sinus tachycardia) or less than 60 beats per minute (sinus bradycardia). Then, any rhythm that originates from outside the sinus node is considered an arrhythmia. Although it is possible to have ectopic impulses from other parts of the heart to control the heartbeat because of sinus bradycardia (this is generally called escape), the arrhythmia that we see most often in clinical practice is the rapid arrhythmia, or tachycardia. Tachycardia is a complex group of arrhythmias that includes many conditions, and this article only briefly introduces the most common or important ones so that patients can accurately understand their condition. Yao Yan, Department of Cardiovascular Medicine, Fu Wai Hospital, Beijing Tachycardia can be divided into several categories according to the location of origin: 1. Atrial tachycardia: Tachycardia of more than 100 beats/min generated by the right or left atrium; usually triggered by aging, infection, genetic mutation, heart valve disease, cardiac surgery, overexertion or long-term alcohol abuse. (1) Focal atrial tachycardia: Often seen in adolescents or the elderly, the lesions are relatively limited. The main manifestation is short bursts of tachycardia, each episode may last only a few seconds, but repeated episodes, often more frequent during exertion and stress. (2) Surgical scar atrial tachycardia: Tachycardia caused by surgical scars in patients who have undergone cardiac surgery. It often coexists with atrial flutter. It usually requires catheter ablation to eradicate and requires a certain level of physician and experience; (3) Atrial flutter: This includes type I (typical) atrial flutter and type II (atypical) atrial flutter. For type I (or typical) atrial flutter, the success rate of ablation by experienced physicians is generally above 90% and may even approach 100%. Type II atrial flutter, however, is more problematic and tends to occur in patients who have undergone cardiac surgery or have undergone AF ablation. It is more difficult to ablate, and the success rate is relatively low, ranging from 50-80%, depending on the patient’s condition and the doctor’s experience. 2.Supraventricular tachycardia: The two main types of tachycardia are atrioventricular node involvement and atrioventricular bypass involvement. So, what is meant by atrioventricular bypass? In a normal person, the atria and ventricles should be completely insulated from the point of view of current conduction, with only a special bundle of wire-like fibers called the AV node-Hitchcock bundle-Pokeno fibers to communicate the current conduction between the atria and ventricles, allowing the atria and ventricles to contract and beat in a sequential manner to supply blood to the whole body. However, some people’s hearts may develop with an extra strand of muscle (often thinner than a hair), and if this muscle strand is just between the atria and the ventricles, it may produce a short-circuiting of the current, and some people may show early muscle contraction in certain parts of the ventricles on the ECG, which we call pre-excitation syndrome. The majority of patients have normal ECGs, whether they have atrioventricular bypass or dual atrioventricular node pathways, and no abnormalities are detected by cardiac ultrasound, CT, MRI, or laboratory tests, but the patient may suddenly feel an accelerated heartbeat under certain circumstances (if you count your own pulse, you may find that it reaches 150 beats/min or even 200 beats/min). This may be stopped by deep inhalation, coughing, stimulation of the throat, or pressure on the eyes, or it may stop suddenly on its own. This condition is called supraventricular tachycardia, or supraventricular tachycardia for short. Supraventricular tachycardia is actually the most common and most easily treated form of tachycardia. To use a common analogy, supraventricular tachycardia is like appendicitis in general surgery in the arrhythmia specialty. The only and best way to treat supraventricular tachycardia is to have a catheter ablation as soon as possible. Ablation of supraventricular tachycardia is the most basic introductory procedure for the ablating surgeon, and safety and success rates are very high, with a success rate of about 92-99% for experienced surgeons. Of course, children should try to wait until they are older before doing it. However, a few patients with supraventricular tachycardia may be more difficult because the bypass and double pathway are too close to the AV node-Hitchcock bundle, due to the fear of injuring the normal heartbeat pathway during surgery leading to AV block (which would require a pacemaker). Also individual bypasses may be too deep to eliminate completely because of their location. However, these are relatively rare cases. 3. Atrial fibrillation: Atrial fibrillation is the most common cardiac arrhythmia. Generally with increasing age, theoretically everyone has the potential to develop atrial fibrillation. Except for atrial fibrillation due to genetics, alcohol consumption, hyperthyroidism, myocarditis, cardiomyopathy, coronary artery disease, and wind heart disease, atrial fibrillation in the vast majority of people is very difficult to identify a specific cause under current medical conditions. For the vast majority of elderly people, it is mainly the result of aging of the heart muscles year by year, so they should face it openly. From a clinical point of view, the manifestations of atrial fibrillation are very variable, with a considerable number of male patients having almost no symptoms, while others mainly show panic, excessive sweating, weakness, shortness of breath, etc. There are also a few patients who will urinate a lot for a short time during an attack and feel weak and uncomfortable afterwards. Some patients usually have sinus node involvement in the right atrium due to aging of the atrial muscles, which usually results in sinus bradycardia and a slow heart rate, but aging of the left atrium may result in atrial fibrillation, which results in a slow heartbeat most of the time and a fast heartbeat in atrial fibrillation, which we call slow-fast syndrome. There are also patients whose heart rhythm is normally normal, but when the atrial fibrillation episode is terminated, the sinus node fails to reissue the impulse in time, and the heart stops for a short period of more than 1 second, or even up to 30 seconds, in which case the patient may faint and become dangerous. However, the greatest danger of atrial fibrillation is first of all in the impact on a person’s quality of life. Secondly, roughly 5% of people may develop a thrombotic brain infarction or other site of infarction, and this risk increases with age and requires warfarin or other medications to prevent it. In addition, atrial fibrillation may exacerbate heart failure if the patient has other heart disease of his or her own – particularly heart failure. As far as treatment is concerned, medication control is necessary. Patients who are not suitable for surgery, especially because of factors such as physical or age conditions, should be controlled with medications. However, for patients eligible for surgery, catheter ablation or surgical ablation is the only chance to eradicate atrial fibrillation. However, the wide range of lesions in atrial fibrillation and, moreover, the incomplete understanding of the mechanisms of its occurrence have led to the variety of procedures now available for its treatment. However, according to internationally accepted data, the primary success rate is roughly 50-60% for the mainstream pulmonary vein large-loop isolation, which may be as high as 70% for paroxysmal AF patients who are relatively young, have had the disease for a short period of time, and have a normal heart on ultrasound, and less for older, enlarged, persistent, or chronic AF. The reasons for this are related to both a lack of understanding of the mechanism and the limitations of the surgical equipment currently used. There may be some improvements in the procedure by some surgeons, but at this time, the success rate is at best about 80%, and it is not a popular procedure. This is the current state of atrial fibrillation ablation. Of course, research in this area is a hot spot in the field of cardiac arrhythmia, and there should be room for improvement in the future, but considering the seriousness and scientific nature of medicine, there should not be much breakthrough in the near future. 4. Ventricular tachycardia: Tachycardia originating in the ventricles is ventricular tachycardia, or ventricular tachycardia for short. The ventricle is the most important part of the heart, and blood is mainly transported by the strong contraction of the ventricle. In other words, these tachycardias generally do not travel unimpeded to the ventricles, but are discounted by the atrioventricular node, so that they are not life-threatening in most cases. Ventricular tachycardia, however, occurs directly in the ventricles, without the AV node as a gate to ensure safety, and the occurrence of ventricular tachycardia usually means that there is a lesion in the ventricular muscle, in which case the risk of ventricular tachycardia is greatly increased. In fact, many physicians have a headache with heart disease because they are afraid of arrhythmias, and the most dangerous of these arrhythmias is mainly ventricular tachycardia and its highest level, ventricular fibrillation, which can lead to sudden death in a very short time, i.e., sudden death. However, there is also a group of idiopathic ventricular tachycardias that occur in patients with an essentially normal heart and are relatively less dangerous. The most important of these are outflow tract ventricular tachycardia and branching ventricular tachycardia. However, for right ventricular cardiomyopathy ventricular tachycardia, coronary ventricular tachycardia, hypertrophic ventricular tachycardia, dilated ventricular tachycardia, and other ventricular tachycardia of organic heart disease, not only are they the most dangerous but also the most difficult to treat. This aspect can be reviewed in my writing on the subject. Patients who have experienced syncope or blackouts should be examined by an arrhythmia specialist as soon as possible and, if necessary, be fitted with a defibrillator, also called an ICD; however, it must be noted that some idiopathic ventricular tachycardias also have syncope or blackouts, but instead of recklessly fitting a defibrillator, catheter ablation should be considered, which is not only less costly but, crucially, can be completely eradicated. For organic ventricular tachycardia that has the potential to cause death, catheter ablation may also be considered in addition to defibrillator installation. However, ablation of this type of tachycardia is the most difficult procedure to perform. Not only should the patient choose it carefully, but the physician should also perform it in strict accordance with the relevant protocols. Furthermore, since ablation is performed in the most critical ventricle, both the patient and the physician must be aware of the importance of protecting the patient’s ventricular muscles as much as possible, and should not strive for the so-called “perfect” outcome in order to avoid the potential long-term harm caused by overtreatment.