Objective To determine the usual triggers of silent and symptomatic ischaemia.

Design Patients wore an ambulatory recorder for 48 hours. The device emitted a tone on detection of ischaemia and patients noted activities, feelings, and symptoms so that ischaemia could be attributed to one of four triggers: physical stress, mental stress, combined physical/mental stress, or no stressor.

Setting Home environment.

Patients Patients (n = 38) with stable coronary disease, positive exercise electrocardiography, and ischaemic episodes on ambulatory electrocardiography.

Main outcome measure Matching ischaemic episodes with perceived triggers.

Results Altogether 257 ischaemic episodes (53% silent) were documented. Triggers were: physical stress, 56%; mental stress, 5%; combined physical/mental stress, 8%; no identifiable trigger, 31%. Episodes associated with mental or no stress were more often silent (69% and 75%, respectively) than those associated with physical stress (45%, p < 0.01), while combined physical/mental stress episodes were usually symptomatic (10% silent, p < 0.01 v other stressors). Although physical stress was less commonly a trigger of silent ischaemia than angina (47%v 65%, p < 0.01), it was still the predominant trigger of silent ischaemia. There was no identifiable trigger in 45% of silent and only 17% of anginal episodes (p < 0.01). Only nine silent episodes involved mental stress alone as a trigger.

Conclusions Daily life ischaemia is usually triggered by physical activity. Mental stress alone is an uncommon trigger of either silent or symptomatic ischaemia, while combined physical/mental stress is a significant but minor trigger of angina. Patients can identify a trigger in 83% of anginal episodes, compared with only half of silent ischaemic episodes.