The orthodermic tachycardia (OT) is clinically distinct from other forms of tachycardia. Its main features are connected with the presence of additional paths through which the wave of excitation passes.
The incidence of orthodromic tachycardia is almost the same as atrioventricular nodal reciprocal tachycardia.
The disease is mainly diagnosed by electrocardiography, if necessary, using other instrumental methods of investigation. Clinically, the pathology is less favorable than reciprocal tachycardia, since higher frequency of heart rate is determined at orthodromy. In some cases, there is a relationship with Wolf-Parkinson-White syndrome (WPW syndrome).
Wolff-Parkinson-White syndrome (WPW) video - causes, symptoms & pathology
Description of orthodromic tachycardia
Pathology develops against the backdrop of latent additional channels of conducting impulses. The mechanism of occurrence is similar to the reentry, since a contour is formed in which the impulse passes anterograde to the ventricles through an atrioventricular node, and retrograde to the atrium, while additional paths of participation take place. Such anterograde holding is not observed with other types of arrhythmias (crying, reciprocal or supraventricular tachycardia).
For orthodromic tachycardia, the launch is not only the onset of extrasystoles, but also ventricular.
Symptoms of orthodromic tachycardia
The disease is characterized by the same manifestations as for reciprocal tachycardia. Patients complain of asthenovegetative disorders in the form of dizziness of weakness, a feeling of ripple in the head and neck.
Characteristic features of orthodromic tachycardia:
- attacks begin and end suddenly;
- the heart rate is 160-200 per minute;
- the rhythm is regular, regular.
Orthodontic tachycardia is often associated with Wolf-Parkinson-White syndrome, which has the following sensations:
- lack of air;
- fading of the heart;
- palpitations, more rhythmic than nerythemic.
In difficult cases, often with the presence of organic pathology of the heart, presyncopoly states and syncope arise.
Causes of orthodromic tachycardia
The development of orthodromic tachycardia may be accompanied by external influences: smoking, excessive alcohol consumption, frequent nervous and physical overvoltages.
The main reason for the occurrence of TB lies in the congenital pathology - the presence of an additional impulse channel, which forms the basis for the formation of tachycardia in the type of reentry. Often, an additional canal is represented by a Kent bundle that connects the atria with the ventricles in addition to the atrioventricular compound.
The additional path of the message does not usually affect the contractility of the ventricles, therefore, the disease without the organic pathology of the heart does not cause hemodynamic disorders.
Types / photos of orthodromic tachycardia
Pathology can manifest itself in two forms:
- Explicit orthodromic tachycardia - during electrocardiography, sinusoidal rhythm defines δ-waves that are similar to those in WPW syndrome.
- The latent orthodromic tachycardia does not appear on electrocardiography, the rhythm remains correct, that is, sinus, while the pulses pass only retrograde.
In the course of its development, the orthodromic tachycardia always involves one of the ventricles in the process of extraordinary pulse. In this connection, the blockade of the leg of Hyza on the lesion side, which leads to a slowing down of the heart rate, often develops.
The blockage of the left leg of Hyza is more characteristic of orthodromic tachycardia than of the atrioventricular nodal reciprocal tachycardia.
Diagnosis of orthodromic tachycardia
Defining an additional path is a rather complicated task. For its execution, often, the mapping of the electric activity of the atrium is used. As a rule, most of the hidden channels are on the left side, so during the attack, the excitation wave first passes along the left atrium. Such changes are fixed by a special probe-electrode.
On the standard electrocardiogram, the following changes are determined:
- We observe the application of the teeth P to the segment ST or the tooth T, which is associated with
- disturbed by the onset of excitation of the atria and ventricles.
- The length of the RP interval, which is 100 ms or more at OP, increases.
- Ventricular QRS complexes are often narrower than broader.
Video WPW Syndrome (Wolf-Parkinson-White) | ECG
Treatment and prevention of orthodromic tachycardia
Similar to that for reciprocal tachycardia. It begins with the restoration of normal sinus rhythm, for which either electropulse therapy or medications combined with vagal tests is used.
After cessation of an attack, the issue is solved with further prevention of paroxysms. Today, increasingly radio frequency ablation is used, with the help of which additional channels of conducting of impulses are crossed.
Before RFC, an electrophysiological study is performed in full, which eliminates other forms of paroxysmal arrhythmia and establishes the exact location of additional channels. In some cases, their number is not limited to two to three ways. Catheter destruction of additional channels is effective in 90% of cases, while the minimum probability of complications is observed.