Conduction system pacing (CSP) was noninferior to biventricular pacing (BiVP) in achieving clinical and echocardiographic response, suggesting that CSP could be an alternative to BiVP, according to results from the CONSYST-CRT trial published May 14 in JACC: Clinical Electrophysiology.

From September 2019 to July 2023, Margarida Pujol-López, MD, et al., randomized 134 patients referred for a CRT indication according to current guidelines 1:1 to CSP or BiVP. Their mean age was 69 years and 27% were women. All patients underwent echocardiography at 15 days and routine clinical device control at 45 days; repeat echocardiography was performed at six and 12 months. Of note, 18 patients crossed over from CSP to BiVP and five crossed over from BiVP to CSP.

Results showed the incidence for the combined primary endpoint of all-cause mortality, cardiac transplant, heart failure (HF) hospitalization or LVEF improvement <5 points at 12 months was similar, occurring in 24% of the CSP group and 30% of the BiVP group, meeting the noninferiority parameters.

Furthermore, noninferiority was met for four secondary endpoints with CSP compared with BiVP respectively, including echocardiographic response (67% vs. 60%), combined endpoint of all-cause mortality, cardiac transplantation and HF hospitalization (12% vs. 18%), QRS shortening measured from fast deflection (–49 ms vs. –45 ms), and NYHA functional class (–0.6 vs. –0.5).

CSP may offer an alternative to BiVP in patients with a CRT indication, write the authors, noting the need for large randomized clinical trials. "Methods to personalize patient CRT therapy according to the underlying conduction disease are highly desirable, rather than seeking to demonstrate superiority of CSP in all clinical scenarios," write the authors.