Electrophysiological examination of the heart - Causes, symptoms and treatment. MF.

Indications for EFI
Contraindications
Preparation for
Study Procedure for
Decoding of results and possible complications of

Among the various disorders of heart rhythm and conductivity, there are diseases that are sometimes very difficult to identify and determine the tactics of their further treatment. These diseases are not always safe, as they can cause serious violations of the heart and subsequent impairment of blood circulation. Therefore, the diagnosis of such arrhythmias is paid special attention, and scientists are constantly expanding the possibilities of using additional research methods in arrhythmology. Since the 60s of the last century, the practice of cardiologists and arrhythmologists began to gradually introduce methods of electrophysiological examination of the heart.

The general principle of these methods is that if a doctor does not manage to "catch" a rhythm disturbance during a single ECG or 24-hour ECG monitoring, it is necessary to stimulate the heart in such a way as to provoke this or that kind of arrhythmia with the possibility to fix it on the subsequent ECG.Stimulation is achieved by means of an electroimpulse effect on the heart, that is, under the influence of a series of impulses a physiological increase in cardiac contractions occurs, which is usually the cause of the appearance of the desired rhythm disturbances.

Electrophysiologic methods of heart examination( EFI) include non-invasive( transesophageal) and invasive research. Invasive is divided into endocardial and epicardial studies.

Endocardial EFI is performed by inserting an electrode through the femoral vein into the ventricle or atrium, and the epicardial stimulation of the is performed in the open heart during cardiac surgery with dissection of the anterior chest wall. Thus, with endocardial examination, the heart is stimulated "from within", with the epicardial heart - from the "external" surface of the heart, and with , the esophagus - from the esophagus( the electrode is in the immediate vicinity of the left atrium).Invasive examination can be an independent diagnostic procedure or be a stage of surgical treatment of arrhythmias( ablation - destruction of pathological pathways in the cardiac muscle).

Transesophageal EFI is performed more often than endocardial, as the latter method requires more powerful technical equipment and expensive equipment, which entails a significant increase in costs. In addition, with non-invasive interventions, the risk of complications is always lower than with the introduction of various probes into the body. But the diagnostic capabilities of the invasive examination are wider, since only the left atrium can be stimulated from the side of the esophagus( due to anatomical features), while during the introduction of the electrode into the chambers of the heart, provocation and ventricular arrhythmias are possible.

Indications for electrophysiological study of

Transesophageal electrophysiological examination of the heart can be prescribed in the following diseases:

- bradyarrhythmias caused by dysfunction of the sinus node,
- paroxysmal supraventricular tachyarrhythmias,
- tachycardia syndrome - bradycardia caused by sinus node weakness syndrome( mainly ciliaryarrhythmia),
- control of the effectiveness of antiarrhythmic drug therapy,
- detection of arrhythmogenic action(Provoking arrhythmia occurrence) of medications,
- determining indications for pacemaker Fitting the ineffectiveness of drug therapy.

Invasive electrophysiological examination is prescribed in situations where the patient has complicated rhythm disturbances or arrhythmias accompanied by severe clinical manifestations and capable of causing death:

- bradyarrhythmias accompanied by loss of consciousness( MES seizures - Morgagni-Edessa-Stokes),
- supraventricular tachycardia( ciliary arrhythmia, ERW syndrome( Wolff-Parkinson-White syndrome), tachycardias from the atrioventricular junction - AB-connections);
- paroxysmal ventricular tachycardia of various forms( can lead to spontaneous development of ventricular fibrillation, which is equivalent to sudden cardiac death),
- atrioventricular blockades of various degrees,
- blockade of the bundle of the bundlebifascicular - the defeat of two branches of the three, as it can lead to the rapid development of a triphasicular blockade, and this condition is life-threatening and can cause sudden cardiac death),
- determination of indications for cardioversion( restoration of sinus rhythm with the help of a cardioverter - apparatus capable of changingrhythm of cardiac contractions by means of electric pulses of a certain power), to the implantation of an artificial pacemaker, or to radiofrequency ablation of additional routes inrdtse in the absence of the effect of drug therapy. Contraindications for electrophysiological examination of the heart

Contraindications for invasive electrophysiological examination of the heart include such conditions as:
- acute myocardial infarction
- acute coronary syndrome
- newly diagnosed and progressive angina
- heart aneurysm or aorta
- heart defects, cardiomyopathies withmarked blood circulation disorder
- severe chronic heart failure
- acute heart failure
- thromboticMobilias, ischemic or hemorrhagic stroke and other acute vascular accidents
- feverish conditions

Contraindications for a transesophageal study, in addition to those listed above, include esophageal lesions, such as diverticula, tumors, strictures( fusion), acute and chronic inflammation in the acute stagein the wall of the esophagus.

Preparation for an EFI for a patient

A patient can be sent to a study from a polyclinic or from the hospital's profile department, where he receives medical and diagnostic help from a cardiologist, arrhythmologist or cardiac surgeon. Both perescheeschevodnoe, and invasive research are conducted strictly on an empty stomach. On the eve of the procedure, you should not abuse coffee, cigarettes and alcohol, and you must cancel all medications that affect the heart and blood vessels, but only in consultation with the attending physician.

Before sending the patient for the procedure, the attending physician should fully examine the patient. The patient must have the results of ECG, daily( Holter) ECG monitoring, Echo - KG( ultrasound of the heart), stress tests( treadmill or veloergometry) on the hands. EEG( electroencephalogram), CT or MRI of the brain( as directed by a neurologist, to exclude the neurological nature of syncope) and consultations of other specialists( neurologist, endocrinologist, vascular surgeon and others) may also be needed.

How is the electrophysiological examination of the heart carried out?

Non-invasive EFI

A transesophageal study of is performed in the functional diagnostic department. The patient comes to the department in the morning, he is invited to the office of ChPEF and placed on a couch, where blood pressure is measured and a normal ECG is recorded. Further, the doctor who owns this technique, explains the essence of the procedure to the patient and proceeds to perform it.

A probe is inserted through the nose or mouth( less often) into the esophagus, at the tip of which there is a miniature electrode that allows recording the electrogram. Also this sensor stimulates the left atrium by transmitting short electrical impulses of a certain current intensity( 10-20 mA).After successful introduction, the probe is attached to the apparatus that stimulates and analyzes the received electrograms.

After stimulation, an electrogram is recorded, on which the appearance of the desired rhythm disturbances is possible. Then the probe is extracted, the doctor analyzes the received data with the help of a computer, and the result is given to the patient's hands or transferred to the ward by the attending physician. Tachyarrhythmia caused in most cases, passes by itself or with the help of medications. In general, the duration of the procedure is 30 to 60 minutes, causing the patient only a slight burning sensation behind the sternum, which is not a pathology in the context of this technique.

Invasive EFI

Invasive electrophysiological study is performed in the department of X-ray diagnostic methods of diagnosis.

Electrodes inserted into the heart cavity

Carrying out the procedure of invasive EFI

The patient is delivered on a gurney from the profile compartment to the cabinet after premedication( intravenous anesthetic and sedative drug), is placed on the operating table, where blood pressure is measured and a standard ECG is recorded. Further, the examining physician pierces the skin in the projection of the femoral( most often) or subclavian vein( rarely) in order to inject an local anesthetic( eg, ultracaine), and then perform a puncture of the vein itself. This is the only unpleasant moment, which can cause slight discomfort in the patient, as the whole procedure is painless.

Then, through a puncture through a special conductor( introducer), a thin flexible catheter is inserted into the vein, under the control of fluoroscopy, moving into the heart cavity. At the end of it there are three to five miniature electrodes performing analogous functions compared to the ChPEPI - recording of electrograms before and after electrostimulation and stimulation itself. The received data are processed by the appropriate equipment, and the result is output.

The procedure lasts for more than an hour, and if it was decided to conduct radiofrequency ablation as the next stage of the operation, the procedure time is extended. After the study, the catheters are removed, a pressure bandage is applied to the punctured vein area and the patient is delivered to the intensive care unit for several hours or a day under the supervision of doctors. After the specified time, he is transferred to the department to which he was hospitalized before.

Interpretation of the results of the

EFI Normally, in the conclusion of the electrophysiological study, it should be indicated that all types of stimulation of the provoked arrhythmias were not revealed.

In the detection of rhythm disturbances and conduction, a complete characterization of each type of arrhythmia is given. Also, the ST segment on the electrogram( depression or lifting) is evaluated in parallel to obtain information on the presence of myocardial ischemia, induced by tachycardia.

The results obtained should be carefully interpreted by the physician arrhythmologist in order to determine the further tactics of managing the patient and correcting the treatment.

Complications in electrophysiological research

Complications in electrostimulation are extremely rare, since over the years of research conducted in this field, the most physiological protocols of stimulation have been achieved, not leading to the development of life-threatening diseases. But still, the doctors conducting the study should be aware of the risk of resuscitation, such as acute heart failure, ventricular fibrillation, sudden cardiac death, and have the skills of conducting emergency and cardiopulmonary resuscitation.

Doctor therapist Sazykina O.Yu.