How to research the mechanisms of non-pharmacological cardiac interventions

Objective To discuss research into the mechanisms of non-pharmacological interventions for cardiac populations. Methods Overview of past research and theory. Results Non-pharmacological interventions for cardiac patients (including: cardiac rehabilitation, heart failure disease management programs and psychosocial interventions) have never been so common or diverse, but also have never been subject to so much scrutiny and skepticism. Better understanding of outcomes of these interventions is an urgent global priority. Mechanisms are the "underlying entities, processes, or structures which operate in particular contexts to generate outcomes of interest." Practice Research into the mechanisms of non-pharmacological interventions offers useful and robust knowledge of how and why cardiac interventions work that can be vital to explaining outcomes from interventions and inconsistencies in results. Conclusions Research into intervention mechanisms can inform the design and optimization of interventions. Implications We recommend that future research into the mechanisms of non-pharmacological interventions for cardiac population 1) view effectiveness as 'somewhat' patterned, 2) conceptualize mechanisms adequately, 3) assume they are hidden, 4) examine how context affects mechanisms, and 6) address what works for whom, when, and why.