Effectiveness of Cardiac Resynchronization Therapy by QRS Morphology in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT).
Summary of "Effectiveness of Cardiac Resynchronization Therapy by QRS Morphology in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT)."
Background- This study aimed to determine whether QRS morphology identifies patients who benefit from cardiac resynchronization therapy with a defibrillator (CRT-D) and whether it influences the risk of primary and secondary end points in patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT) trial. Methods and Results- Baseline 12-lead ECGs were evaluated with regard to QRS morphology. Heart failure event or death was the primary end point of the trial. Death, heart failure event, ventricular tachycardia, and ventricular fibrillation were secondary end points. Among 1817 patients with available sinus rhythm ECGs at baseline, there were 1281 (70%) with left bundle-branch block (LBBB), 228 (13%) with right bundle-branch block, and 308 (17%) with nonspecific intraventricular conduction disturbances. The latter 2 groups were defined as non-LBBB groups. Hazard ratios for the primary end point for comparisons of CRT-D patients versus patients who only received an implantable cardioverter defibrillator (ICD) were significantly (P<0.001) lower in LBBB patients (0.47; P<0.001) than in non-LBBB patients (1.24; P=0.257). The risk of ventricular tachycardia, ventricular fibrillation, or death was decreased significantly in CRT-D patients with LBBB but not in non-LBBB patients. Echocardiographic parameters showed significantly (P<0.001) greater reduction in left ventricular volumes and increase in ejection fraction with CRT-D in LBBB than in non-LBBB patients. Conclusions- Heart failure patients with New York Heart Association class I or II and ejection fraction ≤30% and LBBB derive substantial clinical benefit from CRT-
D:
a reduction in heart failure progression and a reduction in the risk of ventricular tachyarrhythmias. No clinical benefit was observed in patients with a non-LBBB QRS pattern (right bundle-branch block or intraventricular conduction disturbances). Clinical Trial Registration-
URL:
http://www.clinicaltrials.gov. Unique identifier: NCT00180271.
Affiliation
Heart Research, Box 653, 601 Elmwood Ave, Rochester, NY 14642. wojciech_zareba@urmc.rochester.edu.
Journal Details
This article was published in the following journal.
Name: Circulation
ISSN: 1524-4539
Pages: 1061-1072
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21357819
- DOI: http://dx.doi.org/10.1161/CIRCULATIONAHA.110.960898
Medical and Biotech [MESH] Definitions
Cardiac Resynchronization Therapy Devices
Types of artificial pacemakers with implantable leads to be placed at multiple intracardial sites. They are used to treat various cardiac conduction disturbances which interfere with the timing of contraction of the ventricles. They may or may not include defibrillating electrodes (IMPLANTABLE DEFIBRILLATORS) as well.
Cardiac Resynchronization Therapy
The restoration of the sequential order of contraction and relaxation of the HEART ATRIA and HEART VENTRICLES by atrio-biventricular pacing.
Multicenter Studies As Topic
Controlled studies which are planned and carried out by several cooperating institutions to assess certain variables and outcomes in specific patient populations, for example, a multicenter study of congenital anomalies in children.
Automatic Data Processing
Data processing largely performed by automatic means.
Tachycardia, Ectopic Atrial
Abnormally rapid heartbeats originating from one or more automatic foci (nonsinus pacemakers) in the HEART ATRIUM but away from the SINOATRIAL NODE. Unlike the reentry mechanism, automatic tachycardia speeds up and slows down gradually. The episode is characterized by a HEART RATE between 135 to less than 200 beats per minute and lasting 30 seconds or longer.
PubMed Articles
The purpose of this study was to investigate the factors related to sex-specific outcomes for death and heart failure events in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial Wi...
The evaluation of the risk of recurring heart failure events (HFEs) was a pre-specified substudy of MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization The...
This study sought to compare the effects of metoprolol and carvedilol in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) study.
We hypothesized that reductions in left atrial volume (LAV) with a cardiac resynchronization therapy-defibrillator (CRT-D) would translate into a subsequent reduction in the risk of atrial tachyarrhyt...
Clinical Trials
The purpose of this study is to demonstrate that biventricular pacing (BiV) and left univentricular (left ventricular [LV] only) pacing are safe and effective for cardiac resynchronization...
Adaptive Cardiac Resynchronization Therapy Study
The purpose of this study is to show that Adaptive CRT is at least as good at optimizing a patient's cardiac resynchronization therapy (CRT) as the current method of using an echocardiogra...
Ensure Cardiac Resynchronization Therapy Study
The purpose of this study is to gather information on how doctors program particular settings on cardiac resynchronization therapy implantable cardiac defibrillators (CRT-Ds), to analyze h...
REBEAT Resynchronisation and Beta-Blocker European Trial
This protocol will evaluate the effect of cardiac resynchronization therapy (CRT) combined with beta-blocker therapy in patients with symptomatic heart failure in whom beta-blocker therapy...
Clinical Investigation of the Medtronic Concerto™ Device
Heart failure is a progressive disease that decreases the pumping action of the heart. This may cause a backup of fluid in the heart and may result in heart beat changes. When there are ch...
