CRT-D ‘is mysterious,’ especially for non-LBBB patients
“Every time researchers have tried to move beyond the [existing] paradigm of who benefits from CRT-D, it’s never panned out,” commented Jeffrey J. Goldberger, MD, an electrophysiologist, professor, and chief of the cardiovascular division at the University of Miami. “The guidelines are pretty correct on who should get CRT-D. I wouldn’t say that no patients with non-LBBB should get it, but they are less likely to benefit,” although he conceded that responses to CRT-D are highly individualized and hard to predict.
“CRT is mysterious. I’ve had patients who did incredibly well on it,” but “once you start getting outside of where the benefits are proven, you start to run into issues,” Dr. Goldberger said in an interview. “The only solid predictor of a CRT-D response is in patients with LBBB.”
The hospitalizations for heart failure that the University of Rochester investigators assessed as an additional study outcome represent an “important endpoint, but one that is much more subjective than survival,” making its reliability “a bit of a gray area,” he said. The analyses are also limited by being post hoc and, hence, just hypothesis generating.
A recently published analysis of the same dataset by many of the same investigators hinted that CRT-D might reduce HHF in non-LBBB patients when the focus is on recurrent hospitalizations.
Despite the evidence of a survival benefit from CRT-D placement in selected patients, especially those with LBBB, “registry data have shown that use of CRT-D varies widely and has been as low as 27% of eligible patients,” noted Dr. Thomas and Dr. Kutyifa. “There is an opportunity here to understand the barriers to more widespread adoption of CRT-D in appropriate patients,” they said. It is also “possible that CRT-D is overused in non-LBBB patients” given that this subgroup receives about a third of CRT-D devices now. “Future studies should carefully investigate the role of CRT-D in non-LBBB patients.”
MADIT-CRT was funded by Boston Scientific, which markets several CRT-D devices. Dr. Thomas had no disclosures. Dr. Kutyifa has been a consultant to Biotronik and Zoll and has received research funding from Biotronik, Boston Scientific, Spire, and Zoll. Dr Goldberger is director of a not-for-profit think tank on risk stratification for sudden cardiac death that has received unrestricted educational grants from Abbott, Biotronik, Boston Scientific, and Medtronic.
SOURCE: Thomas S et al. HFSA 2020, Abstract 019.