Evolving Indications, Challenges and Advances in Cardiac Resynchronization Therapy for Heart Failure.

Cardiac resynchronization therapy (CRT) via biventricular pacing has markedly improved heart failure outcomes over the past 2 decades. However, some patients show no clinical improvement or evidence of reverse remodeling following device implantation. Challenges include suboptimal patient selection, limitations in the characterization of conduction disease (especially nonspecific interventricular conduction delays), procedural constraints, inappropriate device programming, and delayed referral. Moreover, there remains no formal consensus on evaluating and characterizing CRT efficacy. Underuse persists among women and minoritized racial and ethnic groups. Targeted research addressing unmet needs has led to evolving guideline indications. Novel electrocardiographic and imaging techniques are continually being developed to improve patient selection, and alternative pacing strategies have emerged. Conduction system pacing may allow for a more physiological approach to CRT. Observational studies and small clinical trials have shown comparable or superior efficacy of conduction system pacing over traditional biventricular pacing; however, more studies are needed.