Episodic supraventricular tachycardia (paroxysmal supraventricular tachycardia, SVT) is a rapid, regular arrhythmia in which the heart beats rapidly (mostly 150-200 beats per minute) and neatly during an attack, often with sudden onset and cessation, and is no different from normal when it does not occur. Supraventricular tachycardia is one of the more common types of tachycardia, with a very clear pathogenesis, and can be cured by specific treatments. Because of its commonness, many patients often ask similar questions at different times. Here, I summarize a summary of common clinical problems in the hope of providing help to the majority of patients.
First, the type of supraventricular tachycardia paroxysmal supraventricular tachycardia, there is a narrow sense and a broad sense.
The broad sense refers to the occurrence of tachycardia caused by the etiology above the ventricle. The narrow sense of supraventricular tachycardia is divided into two types, one is atrioventricular node folding tachycardia, and the other is atrioventricular folding tachycardia. The clinical term supraventricular tachycardia generally refers to the narrow definition of supraventricular tachycardia, which is the disease that is the focus of this article.
Atrioventricular node regurgitation tachycardia (AVNRT) occurs when the atrioventricular node has two or more fast or slow conduction pathways that cause tachycardia. Multiple AV node conduction pathways may be present in normal subjects, but only under special circumstances can tachycardia occur.
Atrioventricular reentrant tachycardia (AVRT) is caused by the presence of a bypass between the atria and ventricles in addition to the normal AV node conduction pathway, resulting in reentry. Depending on the parasternal pathway, this type can be divided into the following types: typical preexcitation syndrome (also known as dominant preexcitation, which means that the parasternal pathway has antegrade and usually also retrograde function; this can be confirmed by a general electrocardiogram), occult preexcitation syndrome (the atrioventricular parasternal pathway has only retrograde but not antegrade function, which is difficult to confirm by a general electrocardiogram and needs to be confirmed by esophageal pacing or electrophysiological examination), and persistent junctional tachycardia (PJRT, mostly persistent episodes, tolerated by some patients, but easily leads to tachycardia cardiomyopathy), other special conduction fibers involved in tachycardia.
Second, what are the causes of supraventricular tachycardia?
In a normal person, the electrical activity between the atria and the ventricles can only be conducted through the atrioventricular node, the only conduction pathway, and the electrical activity of the “command” sinus node is conducted from the atria through the atrioventricular node to the ventricles causing the heart to beat normally. In contrast, the onset of supraventricular tachycardia is due to the fact that there is another conduction pathway between the atria and the ventricles that conducts electrical activity (either one or more, often visualized as a “wire”-like structure) in addition to the AV node, which, under certain circumstances, creates a recurrent electrical activity (called in medical terminology In a given situation, the two form a loop of repeated electrical activity (in medical terminology, this is called “folding”), that is, the electrical activity is constantly “circling” (or “shorting”) around a specific loop, resulting in tachycardia. During the onset of tachycardia, many other factors can interfere with the loop (the return loop of electrical activity), thus ending the tachycardia.
What is the clinical picture of supraventricular tachycardia?
The following points are helpful in the determination of supraventricular tachycardia.
1. Rapid heartbeat. This means that the frequency of the heartbeat exceeds the needs of the human physiological state. Generally speaking, the heart rate during episodes of supraventricular tachycardia usually exceeds 150 beats/min, but in some patients, especially when the conduction capacity of the other conduction pathway is poor, it is not uncommon for the heart rate to be 120-130 beats/min during tachycardia.
2. Sudden onset and termination. Generally speaking, the onset of supraventricular tachycardia is sudden and abrupt, that is, from the normal 80 beats/min to the frequency of tachycardia, such as 150 and this frequency will not change greatly. The heartbeat of some patients may increase significantly to about 100 due to discomfort such as nervousness, but it is not the same frequency as the heartbeat during the attack.
3. The heartbeat is regular and uniform. Generally speaking, the heartbeat during an attack of supraventricular tachycardia is relatively regular and neat, and there is no feeling of stopping or going fast and then slow, which means that the supraventricular tachycardia either comes on or ends, and does not change between fast and slow heartbeat frequently. This can be confirmed by the patient’s own pulse measurement.
What is the pattern of development of supraventricular tachycardia?
Supraventricular tachycardia is a disease that has a certain pattern of development: it becomes more and more likely to occur, more and more frequently, and the duration of the attack becomes longer and longer, and later it may not respond to some previously effective termination methods or medications. Supraventricular tachycardia occurs due to the presence of extra conduction pathways (one or more) in the heart. Generally speaking, unless supraventricular tachycardia in infants and children has a certain chance of self-healing, most patients are unlikely to experience self-healing after an episode of supraventricular tachycardia without surgical intervention.
What should I do if I have supraventricular tachycardia?
The treatment of supraventricular tachycardia depends on the specific situation, and is generally divided into treatment during attacks and non-attacks.
1. In acute attacks.
(1) the first attack can first self-monitoring pulse, that is, the heartbeat, to see whether neat regular, while as far as possible to the nearest hospital to do a general electrocardiogram to confirm the supraventricular tachycardia, but also for the next step of treatment to provide judgment information. For patients with multiple episodes, the experience should be better, but it is also better to have an ECG to clarify, because sometimes the feeling is not always accurate.
(2) Termination of supraventricular tachycardia (that is, disrupting this foldback loop by different means so that the electrical activity of the heart does not go around in circles repeatedly).
(1) Neurostimulation method: not recommended for patients with a first attack, and for patients with a first attack it is recommended to have an electrocardiogram to confirm it first! The neurostimulation method also means to affect the electrical activity conduction function of the heart by stimulating some vegetative nerves of the heart, which can achieve effective termination of tachycardia in some patients, and is non-invasive and more economical and practical for patients with brief episodes. For patients with multiple episodes, if the tachycardia cannot be terminated after 3-5 repeated attempts, a hospital visit is recommended. Neurostimulation methods are performed by raising the vagus nerve tone, and the specific methods can be as follows: a. Breath holding: after deep inhalation, hold it hard until you can’t hold it, then exhale, and so on; or conversely, exhale and hold it until you can’t hold it anymore. b. Inducing nausea and vomiting: use other objects such as fingers or chopsticks to stimulate the back wall of the throat to cause nausea and vomiting and other reflexes; c. Cold Water immersion of the face; similar to holding the breath, only with the help of a little cold water stimulation.
(2) Drug termination: intravenous drugs are generally used to terminate tachycardia, which can only be done in the hospital and also requires electrocardiogram confirmation before further medication. Commonly used intravenous drugs include adenosine, isoptin (verapamil), cardioplegia (propafenone), and cortolone (amiodarone).
(3) Esophageal pacing: The electrical impulses are delivered through electrodes to redirect the tachycardia and thereby terminate the tachycardia. It is indicated for patients who cannot be terminated by drugs or who cannot use drugs, such as patients with cardiac insufficiency or women during pregnancy. Of course, the role of esophageal pacing is not only to stop the tachycardia, but also to determine the cause of the tachycardia, such as AVNRT or AVRT.
(4) Electrical resuscitation: It is only suitable for patients with combined supraventricular tachycardia with syncope, unstable vital signs, or for patients with supraventricular tachycardia that cannot be terminated by other pharmacological or non-pharmacological treatments, and is a very effective way to terminate tachycardia by reorganizing it with extracorporeal current. However, it is generally not used because it is invasive, requires anesthesia, and is difficult for most patients to accept.
2, the usual treatment when there is no attack: the current treatment for paroxysmal supraventricular tachycardia, the medical community has no dispute, is definitely recommended to do radiofrequency ablation therapy. Because radiofrequency ablation treatment can achieve the purpose of radical cure, and the procedure has a high success rate, low risk, and low recurrence rate. On the contrary, drug therapy can only terminate part of the supraventricular tachycardia, and the side effects of long-term use are too many, and the value for preventing supraventricular tachycardia attacks is very low.
VI. How is radiofrequency ablation treatment of supraventricular tachycardia performed? How long does it take? What should I pay attention to?
Radiofrequency ablation of supraventricular tachycardia is performed in two steps, which is usually called electrophysiological examination + radiofrequency ablation treatment. The electrophysiological examination first identifies the cause of the supraventricular tachycardia and the corresponding lesion, and then determines whether radiofrequency ablation therapy is needed and can be performed next. The electrophysiological examination is also known as an evocation test (sometimes with the addition of specific drugs to improve the success rate of the evocation) to bring out the tachycardia. When performing electrophysiological examinations, the patient needs to be cooperative and understanding and does not need to be afraid of the attack, because the doctor can always terminate these arrhythmias by specific electrophysiological stimulation. Also these tests are necessary because it is necessary to clarify whether the type of arrhythmia attack is consistent with the patient’s usual attack presentation, etc. The above-mentioned examinations make it possible to clarify the cause of the arrhythmia and the corresponding location of the lesion, and to understand the characteristics of the patient’s cardiac electrical activity. Of course, before the electrophysiological examination, the patient is usually asked to stop the anti-arrhythmic drugs that may affect the test results.
In general, the entire procedure takes about 1-2 hours, but for some special cases, it sometimes takes a long time, and this time requires more understanding cooperation from the patient, because the doctor will always want to give a complete resolution of the lesion, and some lesions are really challenging.
It is usually necessary to prepare and schedule the surgery 1-2 days in advance, and after the surgery the patient is usually hospitalized for 1-2 days for observation to understand the postoperative recovery, especially the changes in the surgical wound. The vast majority of patients can be successfully discharged from the hospital the day after surgery. Of course, if the arrangements go well, the total length of stay is usually about 3 days. If everything goes well, the number of days can even be reduced to 2 days, i.e., the patient is admitted in the morning, checked for the necessary items, and then discharged the next day.
It is especially important to remind female patients that if they are still menstruating, it is usually recommended that they be admitted 1-2 days after they have cleared. Because the procedure is usually performed electively, these are adjustable and have great benefits for their own safety and for reducing hospitalization costs.
What is the cost of radiofrequency ablation of supraventricular tachycardia?
The specific cost of supraventricular tachycardia may vary, and we can only speak about our unit’s experience, because all the materials used are single-use, generally around 20,000, depending on how much and what kind of materials are used in the operation. If there is medical insurance, the patient only needs to bear part of the cost, depending on how the local medical insurance regulations.
What is the success rate of radiofrequency ablation of supraventricular tachycardia? Are there any risks? Will there be recurrence? What should I do?
Supraventricular tachycardia is one of the tachycardias with a well-defined pathogenesis and the most experience in treatment. Theoretically, the success rate of supraventricular tachycardia is around 99%. Of course, the success rate varies from center to center, and in experienced centers, the success rate for supraventricular tachycardia is over 99%.
As an operator, as a physician, as a patient, and as a family member, no one wants risks to occur. But after all, surgery has certain risks that cannot be completely avoided. We can only say that as patients and as operators, both cooperate with each other to avoid complications as much as possible, because we all have the same goal: to solve the faulty lesion safely and beautifully, thus eradicating supraventricular tachycardia. Radiofrequency ablation therapy, as a procedure, is bound to have certain risks, but the incidence of such risks is actually very low, less than 1%. Of course, if it happens, it is a 100% risk for the patient. The so-called risk, in fact, can be understood as: people walking on the road, not to hit the car, but inevitably will unfortunately be hit by a car, only the problem of occurrence or not. Radiofrequency ablation of supraventricular tachycardia is still very mature, and for patients with recurrent episodes, it is recommended that radiofrequency ablation be performed as early as possible, as the benefits far outweigh the possible risks.
In principle, from a technical point of view, although radiofrequency ablation has a very high success rate for supraventricular tachycardia, it should be understood that there is absolutely no 100% success rate in medical treatment. Objectively, recurrence or failure does occur. Prior to radiofrequency ablation, the physician should communicate fully with the patient about these issues, explain the possibility of such cases, and obtain the patient’s informed consent. The incidence of recurrence is about 1%. The causes of recurrence can be multifactorial, ranging from the disease itself to a variety of factors such as surgical instruments and the operator. In cases of post-operative recurrence, secondary ablation can be successful in most cases. In the case of a failed procedure, if the patient is determined to try again after weighing the options and finding an experienced surgeon, there is still a good chance of success. It should be understood that reoperation in cases of failed surgery or post-operative recurrence is a burden on the patient and a test of the surgeon’s skill, courage and patience. (For details, please refer to my article “Analysis of failed ablation and postoperative recurrence of supraventricular tachycardia (including pre-excitation) and recommendations for its management” here?) (For more details, please refer to my article “Analysis of failed ablation and postoperative recurrence of supraventricular tachycardia (including pre-excitation) and recommendations for management”?
Will there be any discomfort after supraventricular tachycardia? What do I need to pay attention to? How long do I need to observe?
For this question, we can only say that most patients do not show any discomfort after surgery. Of course, there are no complications. However, some patients may still have some uncomfortable manifestations such as heartburn and chest tightness. These uncomfortable manifestations do not require special attention after excluding complications, because, after all, the surgery is performed inside the heart, and there is some damage (if there is no damage, the extra pathway cannot be completely cut off!) . So, inevitably, there will be some heart discomfort. However, most of these uncomfortable symptoms can be completely relieved in 1-2 weeks after surgery and do not require special treatment.
In general, antiplatelet drugs (usually aspirin) are required for 2 weeks after supraventricular tachycardia or preexcitation radiofrequency ablation. Other drugs vary according to the underlying disease, and generally no further antiarrhythmic drugs are required after surgery (except beta-blockers for other problems such as blood pressure control).
For patients who have tachycardia, they need to be monitored for tachycardia after surgery. If there is a feeling of tachycardia, it is recommended to have an electrocardiogram done nearby to clarify what kind of tachycardia is present. Not all episodes of tachycardia are paroxysmal supraventricular tachycardia, because other manifestations of tachycardia, such as sinus tachycardia, often occur in normal people! In general, if a recurrence occurs after surgery, it should occur relatively quickly, usually within 1-6 months. In contrast, few patients have recurrence after 6 months. For patients with frequent episodes, recurrence is usually seen 2-3 months after surgery, while for patients with fewer episodes, the treatment can be extended to 6 months later.
For patients without tachycardia but only preexcitation, postoperative observation of recovery of preexcitation is required, which can be observed by general electrocardiography. Likewise, if there is a postoperative recurrence, it should occur relatively quickly, usually within 1-6 months. In contrast, few patients relapse after 6 months. Therefore, for patients with pre-excitation syndrome only, it is recommended to review the ECG at 2 weeks, 1 month, or 3 months after surgery to see if there is a recurrence. Of course, a longer period of time to check the ECG is also possible.
In addition, we would like to remind all patients that the effect of RF ablation surgery for supraventricular tachycardia and preexcitation is very clear, although we do not say 100% success before the surgery, but the actual success rate of supraventricular tachycardia or preexcitation is basically equal to 100% (our center’s experience), that is, there is basically no supraventricular tachycardia or preexcitation that cannot be done. In addition, radiofrequency ablation is a radical procedure, and if you do it well, you can get rid of the disease, and if you succeed, you can look at yourself as if you had never had the disease.