[Truncated abstract] Background: This thesis examines pharmacotherapy use in the secondary prevention of coronary heart disease. It includes antiplatelet agents, beta-blockers, statins and ACE inhibitors, all shown in landmark clinical trials and meta-analyses to reduce the risk of cardiac events in patients with known coronary disease. Underuse of effective preventive therapies represents a lost opportunity to reduce mortality and morbidity. Overseas studies have shown significant underuse of effective therapies at the time of hospital discharge following an acute event and later in ambulatory care. Australian data on prescribing practices following an acute coronary event and, ongoing use in ambulatory care are sparse. Aims: The aim of this thesis was to quantify the prescription of known effective therapies at the time of hospital discharge following an acute coronary event and ongoing use in ambulatory care. A secondary aim was to identify barriers to optimal secondary prevention thus providing an evidential basis to recommend change. Methods: This was an observational study of a cohort of post-MI patients admitted to a tertiary and affiliate hospital in Perth, Western Australia. The continuum of care from the treatment plan at discharge through to the treatment regimen and risk factor management 12 months post-MI was examined. The intermediate step, communication about the treatment plan with the patient and the primary health care provider was also examined. The study involved a review of hospital medical records and follow-up questionnaires to patients and their general practitioners at 3 and 12 months post-MI. All post-myocardial patients were included in the analysis of prescriptions at discharge. The follow-up study included patients 80 years and younger with no terminal conditions. Patient interviews at 3 months and interviews and focus groups with key hospital staff provided qualitative data to inform the quantitative data.