Long-term outcome of catheter ablation and other form of therapy for electrical storm in patients with implantable cardioverter-defibrillators
Long-term outcome of catheter ablation and other form of therapy for electrical storm in patients with implantable cardioverter-def ibrillators
Stanislaw Morawski 0 1
Patrycja Pruszkowska 0 1
Beata Sredniawa 0 1
Radoslaw Lenarczyk 0 1
Zbigniew Kalarus 0 1
0 Silesian Center for Heart Diseases , M.C Sklodowskiej Street 9, 40-055 Zabrze , Poland
1 Department of Cardiology, Congenital Heart Diseases and Electrotherapy, School of Medicine with Division of Dentistry in Zabrze, Medical University of Silesia , M.C Sklodowskiej Street 9, 40-055 Zabrze , Poland
2 Stanislaw Morawski
Purpose Radiofrequency catheter ablation (RFCA) for electrical storm (ES) has become a widely used therapeutic method. Its effectiveness in comparison to other forms of ES treatment is however uncertain. Methods This single-centre retrospective study investigated the long-term clinical outcome after RFCA for ES and compared long-time effects of ablation to other forms of treatment. The study population consisted of 70 consecutive patients hospitalised between January 2010 and June 2015 due to ES. Patients were recruited for the study if the following criteria were fulfilled: first ES caused by ventricular tachycardia (VT) or ventricular fibrillation (VF), implanted cardioverter defibrillator or cardiac resynchronisation therapy device and left ventricular ejection fraction < 50%. The follow-up data on VT/ES recurrence was obtained from pacemaker/implanted cardioverter defibrillator memory. Data on all-cause mortality was collected during outpatient visits or by telephone contact. Results Of the 70 patients enrolled, 28 (40%) were treated with RFCA (group A) and 42 (60%) received other forms of treatment for ES (group B). During a mean (±SD) 864 (629) days of follow-up, death occurred in 4 (14.3%) patients in the ablation group and in 16 (38.1%) patients treated with other methods [p = 0.03]. There was no significant between-group difference in VT/VF and ES recurrence. Statistical analysis revealed that the presence of cardiac resynchronisation therapy device during ES, stroke and/or transient ischaemic attack and lower baseline hematocrit level were the multivariate predictors of all-cause mortality. Conclusions In patients treated with RFCA for ES, all-cause mortality was significantly lower compared to the group treated with other methods.
Electrical storm; Catheter ablation; Ventricular tachycardia; Ventricular fibrillation; Implantable cardioverter-defibrillator
1 Introduction
Heart failure (HF) is a growing medical problem in developed
countries, with incidences among adult population reaching
up to 2% [
1
]. It is well known that HF patients are
simultaneously at a significantly higher risk of sudden cardiac death.
The recommended and most efficient form of primary and
secondary prevention against sudden cardiac death in heart
failure patients is the implantation of automatic implantable
cardioverter defibrillators (ICD) [
2, 3
]. 3.5% of patients with
an ICD for primary prevention, and even 10–40% of those
implanted for secondary prevention of SCD, will suffer from
the most malignant form of ventricular arrhythmia, known as
an electrical storm (ES) [
4, 5
]. An electrical storm is defined as
the occurrence of three or more distinct episodes of ventricular
tachycardia (VT) and/or ventricular fibrillation (VF) within
24 h [
6
]. In patients with ICD, its usual presentation involves
multiple antitachycardia pacing therapies (ATP) and/or
highenergy therapies within a short-time period. Management in
this challenging group is generally focused on the elimination
of potentially reversible causes of electrical instability,
haemodynamic stabilisation and (once reversible causes have been
excluded or dampened) modification of the arrhythmogenic
substrate with catheter ablation of ventricular tachycardia
[
7–9
]. Most of the published data on radiofrequency catheter
ablation (RFCA) for ES is based on small series or case
reports, mainly describing single treatment method. No large
studies have compared RFCA with conservative treatment
and their effects on survival. The purpose of this study
was to assess the long-term clinical outcomes after
RFCA for ES and to compare this method with other
forms of treatment for ES.
2 Methods
2.1 Patients and eligibility criteria
The study population consisted of 70 consecutive patients,
who were hospitalised between January 2010 and June 2015
due to the occurrence of an electrical storm. In 68 patients, the
arrhythmia responsible for the occurrence of ES was VT; in 2,
the ES was due to VF.
Patients were initially recruited for the study if they
fulfilled the following criteria: diagnosed with the first electrical
storm caused by VT or VF, previous or present implantation of
an ICD or cardiac resynchronisation therapy device (CRT-D)
during the first ES hospitalisation, and heart failure with left
ventricular ejection fraction (LVEF) < 50% (assessed by
transthoracic echocardiography). Pati (...truncated)