We conducted a systematic review of controlled trials and pre-post studies to examine whether the putative benefits of telehealth, notably, improvements in clinical outcomes and quality of life, are mediated by increases in knowledge, self-efficacy and self-care behaviour in patients with heart failure. Telehealth was defined as any system of home-based self-monitoring of signs or symptoms of heart failure that transferred data for remote assessment by healthcare providers. Seven electronic databases were searched for studies that assessed any of six pathways in a proposed model. Data were independently extracted by two reviewers. Twelve studies met the inclusion criteria and provided evidence for or against one or more of the six pathways. Although all of the pathways in the model can be theoretically justified and three of the six relationships have been established in heart failure samples outside the context of telehealth, none of the pathways in the model were supported by the telehealth studies reviewed. Failure to replicate previously established relationships emphasizes the weakness of the telehealth literature, which impedes our ability to address questions such as how telehealth might achieve beneficial outcomes.