Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Jan;10(1):55-60.
doi: 10.1016/j.hrthm.2012.09.018. Epub 2012 Sep 18.

QRS narrowing is associated with reverse remodeling in patients with chronic right ventricular pacing upgraded to cardiac resynchronization therapy

John Rickard  1 , Alan Cheng, David Spragg, Daniel Cantillon, Mina K Chung, W H Wilson Tang, Bruce L Wilkoff, Niraj Varma
Affiliations

QRS narrowing is associated with reverse remodeling in patients with chronic right ventricular pacing upgraded to cardiac resynchronization therapy

John Rickard et al. Heart Rhythm. 2013 Jan.

Abstract

Background: Patients with chronic right ventricular pacing (RVP) upgraded to cardiac resynchronization therapy (CRT) have been excluded from the majority of clinical trials of CRT. Little is known about the predictors of response in this population. We hypothesized that reversal of RVP-induced electrical dyssynchrony (indexed by QRS duration) by CRT would predict a favorable response.

Objective: The purpose of this study was to identify baseline characteristics associated with response in patients upgraded to CRT from chronic RVP.

Methods: Consecutive patients presenting for CRT at the Cleveland Clinic between September 30, 2003, and July 8, 2008, with chronic RVP and serial echocardiograms were included in this analysis. RVP was defined as>85% pacing on a pre-CRT device check, previous AV nodal ablation, or complete pacer dependency per chart notes. Response was defined as a reduction in left ventricular end-systolic volume ≥ 15% from baseline. Clinical, ECG, and echocardiographic data were extracted to determine covariates associated with response.

Results: One hundred twelve patients met inclusion criteria, of whom 72 (64.3%) met criteria for response over median follow-up of 9.9 months (interquartile range [6.5-14.7]). No significant differences were noted in terms of male gender (68.1% vs 75.0%; P = .52), ischemic cardiomyopathy (55.6% vs 55.0%; P = 1), pre-CRT QRS duration (189.1 ± 20.7 ms vs 185.5 ± 26.8 ms; P = .47), duration of RVP before CRT upgrade (5.8 ± 3.9 years vs 6.2 ± 4.0 years; P = .57), or baseline left ventricular end-systolic volume (160.0 ± 60.7 mL vs 172.8 ± 67.2 mL; P = .32) between responders and nonresponders, respectively. Percent reduction in QRS duration between the right ventricular-paced and first biventricular-paced waveforms was significantly greater in responders compared with nonresponders (14.4% ± 13.2% vs 7.2%± 14.0%; P = .01). In multivariate analysis, percent reduction in QRS narrowing was the lone factor associated with response (odds ratio 0.02 [0.001-0.42]; P = .01).

Conclusion: Reversal of electrical dyssynchrony predicts response to CRT in chronically RV-paced patients upgraded to CRT. Traditional factors associated with a favorable response to CRT in de novo implants (female gender, nonischemic cardiomyopathy, and wider baseline QRS duration) are not significantly associated with response in upgraded patients. Duration of RVP before CRT upgrade is not an important determinant of response.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Factors commonly associated with a favorable response to cardiac resynchronization therapy (CRT). LVEDV = left ventricular end-diastolic volume; LVESV = left ventricular end-systolic volume.
Figure 2
Figure 2
QRS change indexed to baseline QRS duration and response to cardiac resynchronization therapy.
Figure 3
Figure 3
Distribution of percent reduction in QRS duration across the cohort.
See this image and copyright information in PMC

References

    1. Bristow MR, Saxon LA, Boehmer J, et al. Cardiac resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N Engl J Med. 2004;350:2140–2150. - PubMed
    1. Abraham WT, Fisher WG, Smith AL, et al. Cardiac-resynchronization in chronic heart failure. N Engl J Med. 2002;346:1845–1853. - PubMed
    1. Cleland JG, Daubert JC, Erdmann E, et al. The effect of cardiac resynchronization on morbidity and mortality in heart failure. N Engl J Med. 2005;352:1539–1549. - PubMed
    1. St John Sutton M, Ghio S, Plappert T, et al. on behalf of the resynchronization reverses remodeling in systolic left ventricular dysfunction (REVERSE) study group Circulation. 2009;120:1858–1865. - PubMed
    1. Moss AJ, Hall WJ, Cannom DS, et al. the MADIT-CRT Investigators Cardiac-resynchronization therapy for the prevention of heart-failure events. N Engl J Med. 2009;361:1329–1338. - PubMed