The effect of sodium-glucose co-transporter 2 inhibitors on outcomes after cardiac resynchronization therapy.

AIMS: The trials upon which recommendations for the use of cardiac resynchronization therapy (CRT) in heart failure used optimal medical therapy (OMT) before sodium-glucose co-transporter 2 inhibitors (SGLT2i). Moreover, the SGLT2i heart failure trials included only a small proportion of participants with CRT, and therefore, it remains uncertain whether SGLT2i should be considered part of OMT prior to CRT. METHODS AND RESULTS: We compared electrocardiogram (ECG) and echocardiographic responses to CRT as well as hospitalization and mortality rates in consecutive patients undergoing implantation at a large tertiary centre between January 2019 to June 2022 with and without SGLT2i treatment. Three hundred seventy-four participants were included aged 74.0 ± 11.5 years (mean ± standard deviation), with a left ventricular ejection fraction (LVEF) of 31.8 ± 9.9% and QRS duration of 161 ± 29 ms. The majority had non-ischaemic cardiomyopathy (58%) and were in NYHA Class II/III (83.6%). These characteristics were similar between patients with (n = 66) and without (n = 308) prior SGLT2i treatment. Both groups demonstrated similar evidence of response to CRT in terms of QRS duration shortening, and improvements in LVEF, left ventricular end-diastolic inner-dimension (LVIDd) and diastolic function (E/A and e/e'). While there was no difference in rates of hospitalization (for heart failure or overall), mortality was significantly lower in patients treated with SGLT2i compared with those who were not (6.5 vs. 16.6%, P = 0.049). CONCLUSIONS: We observed an improvement in mortality in patients undergoing CRT prescribed SGLT2i compared with those not prescribed SGLT2i, despite similar degrees of reverse remodelling. The authors recommend starting SGLT2i prior to CRT implantation, where it does not delay implantation.