Coronary heart disease (CHD) is a major cause of morbidity, mortality and economic burden in Australia and the rest of the developed world . Secondary prevention programs, with a focus on risk factor management, have been shown to play a pivotal role in the treatment and management of those affected by CHD. The clinical benefits of secondary prevention, or cardiac rehabilitation programs, include decreased total cardiac mortality (26%), improved quality of life (QOL), and lower rates of rehospitalisation [2, 3]. As such, guidelines recommend that all persons with CHD participate in secondary prevention programs [4, 5].
The traditional and most researched model of secondary prevention consists of participants attending a group outpatient cardiac rehabilitation program for several weeks, including supervised physical activity and CHD risk factor education . However, participation rates in traditional cardiac rehabilitation programs are less than optimal . Witt et al. (2005) reported that in Australia 29% of eligible acute myocardial infarction (MI) patients were referred to cardiac rehabilitation, and only 30% of those referred actually attended, in the United States 29% of MI patients participated, and in Japan only 21% of MI patients participated .
Reported barriers to participation in traditional cardiac rehabilitation programs include patient, provider, health system and societal-level barriers such as: older age, female gender, lower education level, a lack of perceived benefit, work or time constraints, transport difficulties, limited availability of programs, lack of reimbursement, as well as limited social or family support [7, 8]. Therefore, there is an opportunity and challenge in Australia and internationally to provide innovative CHD services to overcome these barriers to participation, and address the significant treatment gap.
Telephone-delivered interventions are convenient and flexible; they can be delivered at a suitable time for the participant and in their own home; and importantly they improve behavioural outcomes following MI [8, 9]. Whilst telephone interventions cannot reach those without access to a telephone, in Australia, approximately 96% of the population live in a household with at least one telephone connection . There are a number of well researched telephone-delivered interventions for CHD patients [11–13] and a large body of literature on home-based and telehealth programs for patients with heart failure  or diabetes . Overall, these programs have been shown to be clinically effective, and in a number of cases, cost-effective as well; they also demonstrate high acceptability to participants . We have developed a novel telephone-delivered secondary prevention program that builds on this earlier work to overcome some of the reported barriers to participation in, and adherence to, currently available cardiac rehabilitation programs (ProActive Heart).
We are trialling a state-of-the-art approach to the delivery of secondary prevention for MI patients through: (i) the recruitment and delivery approach used; (ii) the inclusion of a theoretical framework; and (iii) the content of the ProActive Heart program. First, participants are recruited daily by hospital-based staff, to ensure the research team capture all eligible program participants. ProActive Heart is delivered by project-trained and highly skilled health professionals, or 'Health Coaches', over the telephone. The Health Coaches are based off-site which provides flexibility around the translation of ProActive Heart into clinical practice either utilising telehealth lines or helplines available to CHD patients (such as the Heart Foundation's 'Heartline' in Australia)  or through acute clinical settings.
Second, theory-based health behaviour interventions are known to be more effective than those that are not theoretically-based . ProActive Heart is grounded in Social Cognitive Theory which has been successfully used across a wide range of health behaviour interventions . ProActive Heart has a focus on the core determinants of health behaviour including: knowledge of the risks and benefits of the behaviour; self efficacy or confidence that one can engage in the behaviour under various circumstances; outcome expectations; and specific strategies for achieving positive health behaviour change [19, 20]. Participants develop a personalized action plan (incorporating goal setting) and identification of support networks to enhance behaviour change maintenance. Health Coaches emphasise the benefits of practicing the recommended behaviour, support participants in setting incremental goals to reach the recommended behaviour, with a focus on overcoming self-reported barriers; and provide encouragement to achieve the goal. The intervention targets for addressing individual CHD risk factors are derived from existing national guidelines for the secondary prevention of CHD .
Third, in addition to the lifestyle and medical education and support provided by traditional cardiac rehabilitation programs, we have included psychosocial support (with a focus on depression and social isolation) based on the strong and consistent evidence for an independent causal association between depression, social isolation and lack of quality social support and the causes and prognosis of CHD .
This paper presents the design of a randomised controlled trial (RCT) to evaluate the efficacy of ProActive Heart to improve the coronary risk factor profile and quality of life of MI patients, as well as cost-effectiveness of the program. We hypothesize that participants in the intervention group will have greater improvements in CHD risk factor behaviours and quality of life, than those in the control group. Additionally, we hypothesise that the ProActive Heart program will be cost-effective compared to the control condition. The results of this study will provide valuable new information about an innovative cost-effective secondary prevention program for CHD patients.