Wolff-Parkinson-White syndrome in medical circles is referred to as WPW syndrome. It is characterized by the presence of congenital anomalies of the heart, resulting in premature excitation of his ventricles. Not always a person with such a feature can feel its manifestations - a certain number of patients live without any obvious symptoms of pathology. In other cases, the patient has arrhythmia, tachycardia, some have chest pains, interruptions in the work of the heart, increased sweating, and sometimes loss of consciousness. Such attacks, of course, do not always pose a serious danger to human life and health, but, in any case, require treatment.
WPW syndrome: etiology, developmental mechanism, symptoms
The primary cause of the onset of pathology is congenital abnormality of the heart. The affected person has an additional duct between the atrium and the ventricle, which is called the Kent bundle. Not always the presence of such an anomaly causes health problems to develop. However, if the impulse is cycled in this additional duct, the patient manifests tachyarrhythmia - supraventricular orthodromic orthodromic reciprocal tachycardia, as well as atrial paroxysmal arrhythmia. They provoke an increase in heart rate to 200-340 per minute, which can cause ventricular fibrillation.
The Kent beam is an abnormally developed, rapidly conducting muscle strip of the myocardium. It is located in the region of the atrioventricular sulcus, and connects the ventricle with the atrium, bypassing the usual conductive structure of the heart.
This ventricular connection has the property of a more rapid propagation of the impulse than normal conductive structures, due to which pre-excitation is noted in the ventricles of the heart.
Pathology does not have a large spread, and occurs in approximately 0.15–0.25% of the total population of the planet, with the disease occurring more frequently in men than in women.
All age groups are prone to manifestations of WPW syndrome, however, people between the ages of 10 and 25 face it more frequently, while it is less common in the older age group.
The syndrome of preexcitation develops precisely at the expense of an additional conductive area, which is the knee of the macro-ventricular tachycardia.
Doctors classify the pathology for some features of diagnostic manifestations. There are such types of the disease:
- manifesting: in this case, a combination of delta waves (a sign of the presence of pre-excitation syndrome) and tachyarrhythmias is observed on the ECG;
- hidden: there is no delta wave on the electrocardiogram, the PQ interval is within the normal range, and tachycardia is observed on the background of sinus rhythm;
- plural: in this case two or more Kent beams are present;
- intermittent: on the background of sinus rhythm and arthrioventricular reciprocal tachycardia, transient signs of ventricular prediscussion are recorded;
- The WPW phenomenon is diagnosed in a patient if, as a result of an ECG, he does not have a delta wave, but an arrhythmia is noted.
Among patients with an asymptomatic course, only a third of people under the age of 40 developed symptoms of arrhythmia over time. For those whose pathology was first detected after 40 years, arrhythmia did not occur at all.
Clinical manifestations of the disease are heart palpitations that come and go suddenly, without objective reasons. At the same time, their duration can be from a few seconds to 1-2 hours. The frequency ranges from daily repetition to single attacks several times a year.
In addition to tachycardia, a person feels dizzy, nauseous, faint, or may lose consciousness.
Usually, in addition to such manifestations, the patient does not feel other signs of disorder in the work of the heart.
Prognosis for WPW syndrome, methods of diagnosis and treatment
For patients with diagnosed syndrome, projections are often very optimistic. Even if the syndrome occurs in a form that manifests itself tangibly to a person, it can only in rare, exceptional cases represent a significant danger to life. Thus, there are cases when this pathology and the pre-excitation of the ventricles caused by it became the cause of cardiac arrest.
For a patient, atrial fibrillation carries a serious threat, since in this case the conduction to the ventricles occurs at a frequency of one to one, up to 340 contractions per minute, as a result of which ventricular fibrillation can develop.
The presence of the syndrome can be identified by the results of electrocardiography in 12 leads. Against the background of sinus rhythm, the ECG shows the presence of delta waves, as well as shortening the interval RR, and the expansion of the QRS complex - in this case, the manifesting form of pathology is diagnosed.
The alternation of the presence and absence of delta waves on the ECG indicates the presence of an intermittent form of the disease.
If a normal sinus rhythm and the absence of other changes are recorded on the cardiogram, the diagnosis can be based on the verification of episodes of atrioventricular reciprocal tachycardia.
Echocardiography is prescribed to patients with WPW syndrome to rule out the possibility of congenital heart defects and developmental abnormalities.
In addition, an electrophysiological study (EFI) can be administered, which is able to determine the presence of an additional conductive path, and also shows its electrophysiological characteristics.
One of the options for the treatment of disease is the use of drug therapy. However, firstly, it cannot always help such patients, secondly, in 50-70% of patients with WPW, resistance to specialized drugs develops within 1-4 years from the start of their administration.
The most effective technique that helps get rid of WPW syndrome is radiofrequency ablation.
Radiofrequency ablation - what it is, how it works
RFA of the heart - a procedure that is performed surgically, and using radio frequency energy. As a result, it is possible to normalize the rhythm of the heartbeat. Such intervention is minimally invasive, since it is practically not performed on an open heart or with the commission of large incisions.
For its implementation, a special thin catheter guide is used - it is inserted through a blood vessel, leading to the place where the pathological rhythm is localized. A radio frequency signal is fed through the conductor, which destroys the area of the cardiac structure that generates the wrong rhythm.
For the first time, such operations began to be performed in 1986, and since then, the method of radiofrequency effects on the cardiac system for the treatment of rhythm disorders has been widely used in cardiology.
Indications and contraindications for surgery
As for the indications that are the reason for prescribing the RFA procedure, besides WPW syndrome, they are:
- atrial flutter-flutter;
- ventricular tachycardia;
- AV-nodal reciprocal tachycardia.
There are cases when the procedure is undesirable for the patient, or impossible at all. Contraindications include:
- chronic renal or hepatic failure;
- severe forms of anemia, blood clotting disorders;
allergic reactions to contrast agents and anesthetics;
- hypertension, which is not amenable to correction;
- the presence of infectious diseases and fever in acute form;
- severe heart failure or other minor heart disease;
- hypokalemia and glycoside intoxication.
How is the preparation for RFA
Usually, the appointment of radiofrequency catheter ablation is preceded by an electrophysiological study. In advance, the doctor directs the patient to take some tests, such as a general blood test and a coagulogram.
The conditions of the ambulatory clinic are sufficient for the operation, that is, the patient does not need to go to the hospital of a medical institution.
12 hours before the procedure, the patient should not eat or drink liquid.
The hair in the place where the catheter will be installed (supraclavicular and inguinal region) must be removed.
At bedtime, it is recommended to make a cleansing enema and take a pill for a laxative drug.
The doctor must clarify in advance about the features of taking any medications before the operation. Antiarrhythmic drugs should be excluded for 3-5 days before the planned operation.
Implementation of radiofrequency ablation: the technique of
RFA with WPW syndrome, as with other indications, is performed in an operating room equipped with an X-ray television system to monitor the patient’s condition during surgery. Also, an EPI device, a pacemaker, a defibrillator, and other necessary instruments should be in the room.
Special sedatives are pre-administered to the patient.
Catheters are introduced into the body by percutaneous puncture - through the right or left femoral vein, one of the subclavian veins, as well as through the right jugular vein. In addition, the puncture is carried out through the veins of the forearm.
An anesthetic injection is performed at the puncture site, after which a needle of the required length is inserted into the vessel - a conductor is inserted through it. Next, through the conductor introduces the introducer and the catheter electrode into the desired heart chamber.
After the electrodes are placed in the corresponding heart chambers, they are connected to the junction box, which transmits a signal from the electrodes to a special recording device - this is how the EFI procedure is performed. During the study, the patient may experience minor chest pain, increased heartbeat, discomfort and short-term cardiac arrest. At this point, the doctor, through the electrodes, completely controls the processes of the heartbeat.
The arrhythmogenic zones are affected by the electrode, which is located in the corresponding area, and then the EFI procedure is repeated to check the effectiveness of such an effect.
When RFA has reached the target, the catheters are removed, and the puncture sites are covered with pressure bandages.
What happens after the end of catheter ablation
The patient is transferred to the ward, where he is under the supervision of a doctor throughout the day. In the first few hours after surgery, you must observe strict bed rest and restrict movement completely. Lying is allowed only on the back.
The attending physician explains to the patient the requirements and rules of the recovery process after the operation. During the entire rehabilitation period, which takes up to 2 months, it is necessary to be constantly monitored by a cardiologist, as well as to eliminate heavy physical activity. The patient may be given antiarrhythmic drugs.
Some patients, for example, diagnosed with diabetes, or with impaired clotting properties, may develop some complications such as bleeding at the catheter insertion site, or integrity of the vascular walls due to the introduction of a foreign body, but they are found only in 1% of patients.
RFA in Patients with WPW Syndrome: Efficacy and Prediction
According to the observations of physicians, the primary effectiveness of the procedure is observed in approximately 95% of all operated. The catheter ablation of Kent beams localized in the lateral wall of the left ventricle is slightly higher than those located elsewhere.
Recurrences of the syndrome after RFA are observed in approximately 5% of patients, which may be associated with a decrease in postoperative inflammatory changes and edema. In such cases, it is recommended to repeat the procedure.
Fatal outcome is likely in only 0.2% of patients.
If a person is diagnosed with a multiple form of WPW syndrome, or additional sources of tachycardia, the operation is considered more difficult for the doctor who performs it. If the standard catheterization method does not give a successful result, the physician can apply a non-fluoroscopic electroanatomical 3D mapping and endoepicardial combined approach.
Reviews of doctors and patients about the procedure of the RFA with a symptom of WPW indicate that the procedure is, firstly, quite effective, and secondly, it is almost completely safe for the patient. Special attention should be paid to those patients who have been diagnosed with diabetes, blood clotting disorders, as well as patients aged 75 years and older - they have an increased likelihood of complications during or after surgery. In general, only 5% of people after recurring RFA have relapses of the disease, which re-surgery can cope with.