Mental and Physical Triggers of Silent Myocardial Ischemia: Ambulatory Studies Using Self-Monitoring Diary Methodology

The ability to monitor the electrocardiogram (ECG) during daily life, together with refinements in self-monitoring diary techniques have increased scientific understanding of the effects of physical and mental stress on the heart. During daily life, myocardial ischemia—an important functional measure of the activity of coronary disease—occurs frequently in coronary artery disease (CAD) patients during a wide variety of activities and exhibits characteristic features: it is more frequently asymptomatic or silent; it is triggered at relatively low heart rate elevations compared to controlled exercise testing; and it exhibits a circa-dian rhythm, being more likely in the morning. This article reviews recent ambulatory monitoring studies employing structured diaries, suggesting that behavioral factors, including mental stress, may contribute to these features of out-of-hospital ischemia. Mental stress is shown to be a potent trigger of daily-life ischemia, and silent versus symptomatic episodes have a different profile of physical and mental triggers. Daily activity cycles also appear to contribute to the morning increase in ischemia. Methodological issues in ambulatory ECG/diary studies are considered, especially concerning the reliability and validity of diary reports and problems associated with the analysis of data involving many repeated observations on large numbers of subjects.