Clinical Research
Heart Rhythm Disorder
Implantable Cardioverter-Defibrillator Patients Who Are Upgraded and Respond to Cardiac Resynchronization Therapy Have Less Ventricular Arrhythmias Compared With Nonresponders

https://doi.org/10.1016/j.jacc.2011.08.038Get rights and content
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Objectives

The purpose of this study was to evaluate the impact of upgrading implantable cardioverter-defibrillator (ICD) therapy to cardiac resynchronization therapy (CRT) combined with defibrillator (CRT-D) on the occurrence of ventricular arrhythmia (VA) and appropriate ICD therapies.

Background

CRT has been shown to improve left ventricular (LV) systolic function and induce reverse LV remodeling. In addition, it has been hypothesized that CRT may reduce the incidence of VA.

Methods

Heart failure patients receiving an upgrade from ICD to CRT-D were evaluated. Patients were considered responders to CRT if LV end-systolic volume reduced ≥15% at 6 months of follow-up. Episodes of VA, triggering device therapy (anti-tachycardia pacing and shocks) were recorded before and after upgrade for the overall population. In addition, these outcomes were compared between CRT responders and nonresponders during the follow-up period after CRT response was assessed.

Results

One hundred fifteen patients (93 males [81%], age 65 ± 12 years) were evaluated during a mean follow-up of 54 ± 34 months before CRT-D upgrade and 37 ± 27 months after upgrade. In CRT responders (n = 70), the frequency of VA requiring appropriate device therapy demonstrated a trend toward a decrease from 0.51 ± 0.79 to 0.30 ± 0.59 per patient per year after CRT-D upgrade (p = 0.052). In CRT nonresponders (n = 45), the frequency of VA requiring appropriate device therapy significantly increased from 0.40 ± 0.69 to 1.21 ± 2.53 per patient per year after CRT-D upgrade (p = 0.014).

Conclusions

After upgrade from ICD to CRT-D, nonresponders to CRT showed a significant increase in VA burden requiring appropriate device therapy.

Key Words

cardiac resynchronization therapy
device upgrade
implantable cardioverter-defibrillator
remodeling
ventricular arrhythmias

Abbreviations and Acronyms

CI
confidence interval
CRT
cardiac resynchronization therapy
CRT-D
cardiac resynchronization therapy-defibrillator
EF
ejection fraction
ICD
implantable cardioverter-defibrillator
LV
left ventricular
LVEDV
left ventricular end-diastolic volume
LVEF
left ventricular ejection fraction
LVESV
left ventricular end-systolic volume
NYHA
New York Heart Association
VA
ventricular arrhythmia
VT
ventricular tachycardia

Cited by (0)

Dr. Delgado received consulting fees from St. Jude Medical. Dr. van Erven received research grants from Boston Scientific. Dr. Bax received research grants from Biotronik, Boston Scientific, GE Healthcare, Medtronic, and St. Jude. Dr. Schalij received research grants from Biotronik, Boston Scientific, and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Steven E. Nissen, MD, MACC, served as Guest Editor for this paper.