Analysis of electrotherapy of cardioverter defibrillators implanted for the primary prevention of sudden cardiac death

Aim. To assess various types of electrotherapy and the reasons for its use in patients with implanted cardioverter defibrillators (ICD) for primary prevention of sudden cardiac death (SCD).Material and methods. A retrospective single-site study of 308 patients with implanted cardioverter defibrillators was conducted. Patients were divided into 2 groups: 1 — patients with persistent paroxysmal ventricular tachycardia (VT)/ ventricular fibrillation (VF); 2 — patients without persistent paroxysms of VT/VF. The standard ICD programming protocol was carried out intraoperatively, at 3-4 days after the implantation, then 1 time in 12 months, as well as unscheduled on request. Primary data was collected about paroxysms of ventricular and supraventricular rhythm disturbances, episodes of unmotivated detection of tachyarrhythmias, adequacy of use and types of ICD electrotherapy. The period of dynamic observation was 7 years.Results. The group with an increased risk of persistent paroxysmal VT/VF is patients with ischemic genesis of chronic heart failure (CHF), repeated myocardial infarction, persistent atrial fibrillation (AF), as well as with recorde episodes of unstable VT and ventricular extrasystoles at programming visits. In 54,1% of cases with persistent paroxysms of VT/VF, unjustified detection of ventricular arrhythmias was established. Its causes were: 1) AF with a high heart rate; 2) T-wave detection; 3) sinus tachycardia in the area of detection of VT; 4) atrial flutter with a high heart rate.Conclusion. In patients with primary prophylaxis of SCD, the use of ICD electrotherapy takes place not only due to paroxysms of VT/VF, but also because of both paroxysms of supraventricular rhythm disturbances and other features of rhythm perception by the device. To reduce the number of unjustified triggers during the installation of ICD electrotherapy program in patients with AF/atrial flutter, it is advisable to use a dedicated area of monitor VT and programmed long-term tachycardia detection for adequate rhythm discrimination.