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CRT beneficial for older HF patients with LBBB, longer QRS duration
In older patients with HF, the greatest benefits of cardiac resynchronization therapy were observed in those with left bundle-branch block and longer QRS duration, according to results of a retrospective cohort study.
In patients with HF aged 65 years or older, use of a CRT defibrillator (CRT-D) was associated with lower risk for death from any cause and hospital readmission if the patient had left bundle-branch block (LBBB) and QRS duration ≥150 ms.
Pamela N. Peterson, MD, MSPH, and colleagues undertook the study because CRT-D implantation can be risky and expensive, yet as many as half of HF patients who receive it do not improve, they wrote in the study background.
Using data from the National Cardiovascular Data Registry’s ICD Registry, the researchers analyzed 24,169 patients (mean age, 75 years; 68% men; 90% white) aged 65 years or older with a record of admission for CRT-D implantation from April 2006 to December 2009. All were enrolled in fee-for-service Medicare at the time.
Outcomes of interest included death from any cause, readmission for any cause, CV and HF readmissions, and complications.
Patients with LBBB and QRS duration ≥150 ms had a lower mortality rate after 3 years (20.9%) compared with those with LBBB and QRS duration 120 ms to 149 ms (26.5%; HR=1.30; 95% CI, 1.18-1.42), those with no LBBB and QRS duration ≥150 ms (30.7%; HR=1.34; 95% CI, 1.2-1.49), and those with no LBBB and QRS duration 120 ms to 149 ms (32.3%; HR=1.52; 95% CI, 1.38-1.67).
Patients with LBBB and QRS duration ≥150 ms were also at lower risk for all-cause readmission (38.6%) than those in any other group.
The only association with complications detected was a greater risk for 3-year infection for patients with no LBBB and QRS duration 120 ms to 149 ms compared with those with LBBB and QRS duration ≥150 ms (HR=1.4; 95% CI, 1.01-1.94).
“This study provides an important perspective on the role of QRS duration in outcomes after CRT implantation in clinical practice,” Peterson, of Denver Health Medical Center, and colleagues wrote. However, because the study had no control group that did not undergo CRT, “our results should not lead to conclusions regarding the benefit of CRT, or the lack thereof, in patients with QRS duration of 120 ms to 149 ms and without LBBB.”
Disclosure: See the full study for a list of the researchers’ relevant financial disclosures.