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Noninvasive topical diagnostics and radiofrequency ablation of ventricular arrhythmia
DOI: http://dx.doi.org/10.20534/ESR-17-3.4-63-64
Khamrayev Ramesh Ravshanovich, Salayev Oybek Sabirzhanovich, Yakubov Akmal Abdusamatovich, Mullabayeva Guzal Uchkunovna, Kurbanov Ravshanbek Davletovich Republican Specialized Center of Cardiology, Uzbekistan
E-mail: Guzal-m@inbox.ru
Noninvasive topical diagnostics and radiofrequency ablation of ventricular arrhythmia
Absrtact: The article provides data on 35 patients with ventricular arrhythmias of non-ischemic etiology, who underwent radiofrequency ablation. Topical diagnostics was performed on the basis of12-lead electrocardiogram according to algorithms, which again confirmed their rapid response. The effect of RFA was full except for the ventricular arrhythmia that was caused by organic pathology.
Keywords: ventricular tachycardia, radiofrequency ablation, electrophysiological study.
Patients with non-coronary ventricular tachycardia (VT) represent a fairly heterogeneous group and constitute about 10% of all ventricular heart rhythm disturbances (HRD) [1]. It is believed that non-coronary ventricular arrhythmias, especially idiopathic, which occur in perfectly healthy people, are safer and have a favorable prognosis [2]. However, even really idiopathic ventricular arrhythmias subjectively are often poorly tolerated by patients, significantly deteriorating their quality of life, disturb hemodynamics and may lead to myocardial remodeling and formation of the so-called arrhythmogenic cardiomyopathy and ultimately to the development of heart failure. Often solely the factor of presence of arrhythmia deteriorates significantly the patients' quality of life, leads to the work decrement and social maladjustment. Therefore, it is very important to develop and improve the methods for timely diagnostics and treatment of heart rhythm disturbances [3; 4; 5]. It should be noted that drug therapy in patients with ventricular HRD is often inefficient or completely inefficient. In addition, for many patients, especially young, who consider themselves to be healthy, it is psychologically difficult to tolerate the need for daily consumption of medicines. Modern approaches to the treatment of cardiac arrhythmias are associated with active introduction of new methods of electrophysiological diagnostics and interventional treatment options into clinical practice. In recent years it was demonstrated that catheter ablation of non-coronary ventricular arrhythmias is an effective and rather safe method of treatment [6]. At the present time the Republican Specialized Center of Cardiology of Uzbekistan (RSCC) has an experience of using the radio-frequency ablation (RFA) ofvarious HRD. Temporary absence of navigation system for a more accurate topical diagnostics reduces the possibilities for surgical treatment of HRD. However, as shown in the studies, adherence to the algorithms of ECG-diagnostics of the arrhythmogenic focus location allows to make a differentiated approach to the selection of patients for RFA.
Objective: assessment of effectiveness of RFA in the patients with VT, depending on their topography (based on the analysis of standard 12-lead ECG) without use of navigation system.
Materials and methods: 35 patients at the age from 18 to 48 years (average age 30±12,6 years) were examined in the department for surgical treatment of HRD at RSCC. Strongly pronounced symptoms of arrhythmia were observed in all patients: 18 persons had past syncopal conditions in anamnesis, 20 persons complained
of dizziness, 33 patients felt cardiac malfunctions; all patients experienced the shortness of breath on exertion. Thus, no case of asymptomatic course ofventricular HRD was observed. 9 patients had the signs ofpast myocarditis, 26 patients were diagnosed with "idiopathic VA". The selection of anti-arrhythmic therapy was performed for all patients at the prehospital stage, which included cordarone, a combination of several anti-arrhythmic drugs of different classes, which turned out to be ineffective. All patients underwent: analysis of the morphology of ectopic ventricular complexes, which were recorded by the body-surface 12-lead ECG; daily ECG monitoring by Holter; blood test for thyroid hormones; echocardioscopy; coronarography (on indications); endocardial electrophysiological study (EPS). Under daily ECG monitoring by Holter, a significant number of extrasystoles was marked in all patients: from 8000 and more within 24 hours. In 29 patients the frequent monomorphic ventricular extrasystole (VE) was the main manifestation of ventricular arrhythmia (VA).
The conventional algorithms of ECG were used as a criterion for location of VE [7; 8].
After conduct of electrophysiological study and receipt of criteria concerning this type of arrhythmia, RFA of the arrhythmogenic zone was performed. The criterion for arrhythmia from the right ventricular outflow tract (RVOT) was the outrunning of early activity by 30-55 ms as to QRS-complex on the body-surface ECG, for the fascicular left ventricular tachycardia (FLVT) x - spike of the Purkinje fibers in the posterior branch of the His bundle in 2 cases and in the anterior branch in 3 cases on the attack of tachycardia. The average procedure time amounted to 60 minutes. The average number of RFA-exposure was 3; the intensity of exposure amounted to 35-40W, the average effective temperature was 50-57 degrees. The criteria for effective ablation were as follows: elimination of the existing arrhythmia, impossibility for induction of arrhythmia affected by stimulation under re-entry tachycardias and the absence of focal activity under ectopic arrhythmias. Repeated Holter monitoring was performed a month after RFA.
Results and their discussion:
Studies have shown that arrhythmogenic focus in the case of non-coronary ventricular extrasystole is detected in more than half of the cases in the region of the right ventricular outflow tract, which corresponds to our data, when this localization of arrhythmogenic focus was revealed in more than half of the patients.
Section 5. Medical science
This zone is a complex three-dimensional structure, and the conduct of intraoperative mapping takes time [9]. In this regard, it is important to develop non-invasive methods of pre-surgical topical diagnostics of non-coronary extrasystole. The use of such methods would allow to narrow the search area of the arrhythmogenic focus, to reduce the time of intraoperative fluoroscopy. At the present time several algorithms for topical diagnostics ofventricular extrasystole have been suggested based on the standard 12-leads ECG [7; 8]. These algorithms show a fairly high specificity and sensitivity in the terms of defining the belonging of arrhythmogenic focus to different anatomic zones of the ventricles (the front wall of RVOT, antero-septal region of the right ventricle, etc.). Comparison of the data of ECG-analysis and intracardiac electrophysiology study showed a coincidence of arrhythmogenic focus localization in all cases.
So, according to the obtained data the localization of VA from RVOT was detected in 21 patients (60%), in the projection ofthe right sinus of Valsalva - in 5 patients (14,2%), para-Hisian localization was diagnosed in 1 patient (2%), fascicular VT - in 5 patients (14,2%), localization irom the region of the interventricular septum - in 1 case (2,8%), from the right ventricular basal segment - in 2 cases (5,7%).
According to the summarized data of numerous literature sources, the efficiency of catheter ablation for VA totally amounted to 75-95%. With structurally normal heart, especially in the case of RVOT tachycardia, the efficiency of RFA may be up to 97% according to some reports, but more often it amounts to about 80%, with recurrences in 5% of the cases [10; 11].
As the analysis of our own results has shown, if VA was localized in RVOT, the efficiency was observed in 20 cases (95%).
We did not manage to obtain positive results in the case when the arrhythmogenic focus was localized in the sidewalls and in the region of moderator band, which corresponds to the data of other authors [3]. This is explained by the presence of structural pathology (past myocarditis) in patients. According to the classification of ventricular HRD there is a special group of fascicular VT. As a rule, a benign arrhythmia is observed in such patients [3]. In our case, the effect in the case of fascicular VT with the absence of organic
cardiac pathology was full. When the arrhythmogenic focus was
localized in the projection of the Valsalva sinus and in para-Hisian region, the effect of RFA was absolute immediately after surgery and a month after RFA. It should be noted that the procedure in the latter case was complicated by the development of complete right bundle branch block.
Conclusion
The results of our analysis confirmed once again that RFA of VHRD is a highly effective and relatively safe method of arrhythmia treatment. We demonstrated the specificity and sensitivity of ECG algorithms for topical diagnostics of arrhythmia. On the basis of accurate localization of arrhythmogenic focus it is possible in advance to predict the outcome of RFA. The presence of structural pathology does not allow to obtain the absolute effect from the procedure of RFA.
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