Patients' willingness to undertake secondary preventive strategies following heart attack are likely to be affected by their understandings of their condition. This qualitative study explored patients' understandings of heart attack in order to contribute to the design of effective secondary prevention services. In-depth interviews were conducted with 25 patients with myocardial infarction (MI). These data indicate that information received from health professionals encourages patients to view heart attack as an acute event rather than a symptom of a chronic condition and that this understanding provides patients with low motivation for long-term lifestyle change. Patients may benefit from understanding a heart attack as an acute symptom of an underlying disease process which long-term medication and behavioural change can help to check. In order to achieve this, health professionals need to examine patients' understandings of their heart attack and recovery and to provide information about lifestyle which engages with these understandings.