Heart failure patients who are more likely to benefit from implantation of pacemaker

August 13, 2013

In a large population of Medicare beneficiaries with heart failure who underwent implantation of a cardiac resynchronization therapy defibrillator, patients who had the cardiac characteristics of left bundle-branch block and longer QRS duration had the lowest risks of death and all-cause, cardiovascular, and heart failure readmission, according to a study in the August 14 issue of JAMA.

"Clinical trials have shown that (CRT) improves symptoms and reduces mortality and readmission among selected and left ventricular systolic dysfunction. Following broad implementation of CRT, it was recognized that one-third to one-half of receiving the therapy for do not improve. Identification of patients likely to benefit from CRT is particularly important, because CRT defibrillator (CRT-D) implantation is expensive, invasive, and associated with important procedural risks. A primary question regarding optimal patient selection for CRT is whether patients with longer QRS or left bundle-branch block (LBBB) morphology derive greater benefit than others," according to background information in the article. QRS duration is a measurement of the electrical conducting time of the heart on an . Left bundle-branch block is a abnormality.

Pamela N. Peterson, M.D., M.S.P.H., of Denver Health Medical Center, Denver, and colleagues conducted a study to determine the long-term outcomes of patients undergoing CRT-D implantation and associations between combinations of QRS duration and presence of LBBB and outcomes, including all-cause mortality; all-cause, cardiovascular, and heart failure readmission; and complications. The study included Medicare beneficiaries in the National Cardiovascular Data Registry's ICD Registry between 2006 and 2009 who underwent CRT-D implantation. Patients were stratified according to whether they were admitted for CRT-D implantation or for another reason, then categorized as having either LBBB or no LBBB and QRS duration of either 150 ms or greater or 120 to 149 ms. Patients underwent follow-up for up to 3 years, through December 2011.

Mortality rates in the primary overall study cohort were 0.8 percent at 30 days, 9.2 percent at 1 year, and 25.9 percent at 3 years. Rates of all-cause readmission were 10.2 percent at 30 days and 43.3 percent at 1 year. The researchers found that after adjustment for demographic and clinical factors, compared with patients with LBBB and QRS duration of 150 ms or greater, the other 3 groups had significantly higher risks of mortality and all-cause, cardiovascular, and heart failure readmission. The adjusted risk of 3-year mortality was lowest among patients with LBBB and QRS duration of 150 ms or greater (20.9 percent), compared with LBBB and QRS duration of 120 to 149 ms (26.5 percent), no LBBB and QRS duration of 150 ms or greater (30.7 percent), and no LBBB and QRS duration of 120 to 149 ms (32.3 percent). The adjusted risk of l-year all-cause readmission were also lowest among patients with LBBB and QRS duration of 150 ms or greater (38.6 percent), compared with LBBB and QRS duration of 120 to 149 ms (44.8 percent), no LBBB and QRS duration of 150 ms or greater (45.7 percent), and no LBBB and QRS duration of 120 to 149 (49.6 percent).

There were no observed associations with complications.

"Although prior data regarding the effects of CRT as a function of QRS duration are largely limited to meta-analyses of clinical trials, this study provides an important perspective on the role of QRS duration in outcomes after CRT implantation in clinical practice," the authors write.

"These findings support the use of QRS morphology and duration to help identify patients who will have the greatest benefit from CRT-D implantation."

Explore further: HFSA updates recommendations for use of cardiac resynchronization therapy

More information: JAMA. 2013;310(6):617-626

Related Stories

HFSA updates recommendations for use of cardiac resynchronization therapy

February 27, 2012
Based on a review of the latest evidence, the Guidelines Committee of the Heart Failure Society of America now recommends that the use of cardiac resynchronization therapy (CRT) be expanded to a larger group of patients with ...

Pacemaker implantation for heart failure does not benefit nearly half of the patients

June 13, 2011
A new meta-analysis study, led by physician researchers at University Hospitals (UH) Case Medical Center and Case Western Reserve University School of Medicine, and to be published in the Archives of Internal Medicine, shows ...

Sudden cardiac death higher in men with slower electrical impulses through heart

May 21, 2012
Men whose electrical impulses take a few milliseconds longer to travel through the lower chambers of the heart have an increased risk for sudden cardiac death (SCD), according to research reported in Circulation, an American ...

Heart Failure: Targeting the right patients for CRT-D

May 22, 2011
Patients with dyssynchronous yet viable ventricles are most likely to benefit from cardiac resynchronization therapy combined with defibrillation, concludes the latest analysis of the MADIT CRT trial. The CRT-MADIT-CRT trial ...

Recommended for you

Five vascular diseases linked to one common genetic variant

July 27, 2017
Genome-wide association studies have implicated a common genetic variant in chromosome 6p24 in coronary artery disease, as well as four other vascular diseases: migraine headache, cervical artery dissection, fibromuscular ...

Could aggressive blood pressure treatments lead to kidney damage?

July 18, 2017
Aggressive combination treatments for high blood pressure that are intended to protect the kidneys may actually be damaging the organs, new research from the University of Virginia School of Medicine suggests.

Quantifying effectiveness of treatment for irregular heartbeat

July 17, 2017
In a small proof-of-concept study, researchers at Johns Hopkins report a complex mathematical method to measure electrical communications within the heart can successfully predict the effectiveness of catheter ablation, the ...

Concerns over side effects of statins stopping stroke survivors taking medication

July 17, 2017
Negative media coverage of the side effects associated with taking statins, and patients' own experiences of taking the drugs, are among the reasons cited by stroke survivors and their carers for stopping taking potentially ...

Study discovers anticoagulant drugs are being prescribed against safety advice

July 17, 2017
A study by researchers at the University of Birmingham has shown that GPs are prescribing anticoagulants to patients with an irregular heartbeat against official safety advice.

Protein may protect against heart attack

July 14, 2017
DDK3 could be used as a new therapy to stop the build-up of fatty material inside the arteries


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.