CRT Efficacy in "Mid-Range" QRS Duration Among Asians Contrasted to Non-Asians, and Influence of Height

Abstract

Objectives: The purpose of this study was to test the hypotheses that cardiac resynchronization therapy (CRT) efficacy differed among Asians compared with non-Asian populations, differed between QRS duration (QRSd) ranges 120-149 and ≥150 ms, and was influenced by height in the multinational ADVANCE CRT trial.

Background: CRT guidelines, derived from trials among U.S./European patients, assign weaker recommendations to those with midrange QRSd (QRSd <150 ms). Patient height may modulate CRT efficacy. Together, these may affect CRT prescription and efficacy in Asia.

Methods: CRT response was assessed using the Clinical Composite Score 6 months postimplant (n = 934). Heart failure events and cardiac deaths were reported until 12 months. Asian and non-Asian patients were compared overall, by QRSd <150 ms (Asian n = 71 vs non-Asian n = 248), and QRSd ≥150 ms (Asian n = 180 vs non-Asian n = 435) and by height.

Results: Asians comprised 27% (251 of 934) of the primary study population. More Asians had QRSd ≥150 ms (72% [180 of 251] vs 64% [435 of 683] in non-Asian patients; P = 0.022). Overall CRT response was better in Asians vs non-Asians (Clinical Composite Score 85% vs 65%; P <0.001), and following QRSd dichotomization (QRSd <150 ms: 80% vs 59%; P <0.001; QRS ≥150 ms: 86% vs 69%; P < 0.001). HF events and cardiac deaths were fewer in Asians irrespective of QRSd (P < 0.001). Stepwise multivariable analysis indicated that in group QRSd <150 ms, nonischemic cardiomyopathy, number of other comorbidities (0-1 vs ≥4), and atrial fibrillation influenced CRT response. The trend favoring Asian race (OR: 1.46; 95% CI: 0.72-2.95) was eliminated (OR: 1.00; 95% CI: 0.47-2.11) when height or QRSd/height were included (QRSd/height P = 0.006; OR: 1.64; 95% CI: 1.15-2.35). In QRSd <150 ms, probability of CRT response diminished as height increased, but increased with QRSd/height, in both Asians and non-Asians. In QRSd ≥150 ms, height or QRSd/height had minimal effect in Asians or non-Asians.

Conclusions: Height modulates CRT efficacy among patients with QRSd <150 ms and contributes to high probability of benefit from CRT among Asians. CRT should be encouraged among Asian patients with midrange QRSd. (Advance Cardiac Resynchronization Therapy [CRT] Registry; NCT01805154).

Keywords: Asian; CRT; QRS duration; height; race.

Conflict of interest statement

Funding Support and Author Disclosures This registry was funded by Abbott. Dr Varma has received consulting fees/honoraria from Abbott, Boston Scientific, Biotronik, Medtronic, and Impulse Dynamics. Dr Sethi has received research support from Abbott. Dr Kondo has received consulting fees/honoraria from Abbott, Boston Scientific, Biotronik, Daiichi-Sankyo, and Bayer. Dr Joung has received research funds from Abbott and Medtronic. Dr Auricchio has served as a consultant for Boston Scientific, Backbeat, Biosense Webster, Cairdac, Corvia, EBR Systems, Microport CRM, Philips, and Radcliffe Publisher; has received speakers fees from Boston Scientific, Medtronic, and Microport CRM; has participated in clinical trials for Boston Scientific, EBR System, Medtronic, and Philips; and has intellectual properties with Boston Scientific, Biosense Webster, Microport CRM, and Daiichi-Sankyo. Dr Singh has received consulting fees/honoraria from Biotronik, Boston Scientific, Medtronic, Abbott, Microport, EBR, Respicardia, Impulse Dynamics, BackBeat Inc., and Toray Inc. Dr Lee has received a salary from Abbott. Dr Gold has received consulting fees/honoraria from Abbott, EBR, Medtronic, and Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

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