I t is generally agreed that oxygen requirements during sexual activity are moderate’.*; heart rate values during intercourse arc similar to those found in daily life’*; sexual activity in most patients with coronary artery disease (CAD) is associated with low risk of cardiac complications’; and coital death among patients with CAD is rare.’ There is, however, a paucity of relevant data on sexual activity in patients with CAD. The occurrence of silent ischemia during sexual intercourse in patients with coronary disease is among the issues that still require elucidation. This study utilized ambulatory elcctrocardiographic monitoring to detect the occurrence of ischemia during intercourse in patients with CAD. The relation between electrocardiographic findings on sexual activity and a near-maximal exercise test were compared. . . . The study group comprised 88 male CAD outpatients, mean age 52 years (range 36 to 66), who participated in our long-term cardiac rehabilitation program. Patients’ informed consent to undergo 24-hour ambulatory electrocardiographic monitoring, which included monitoring during sexual activity, was a prerequisite for admission into the study. The diagnosis of CAD was established by one or both of the following criteria: previous myocardial infarction (73 patients [83%]) and typical effort-induced angina (15 patients [17%]). Functional capacity (New York Heart Association classification) was established as class I for SO patients (57%), class II for 26 (30%), and class I11 for 12 (14%). All patients were in sinus rhythm and had been clinically stable for at least 4 months. None had anemia, respiratory disease, or chronic renal failure. Patients with cchocardiographic evidence of left ventricular hypertrophy or cardiomyopathy were excluded from the study, as were patients using digitalis, diuretics, or antiarrhythmic medication. Beta-blocking agents were discontinued 24 days before examination, and nitrates and calcium channel blockers were discontinued 224 hours before examination. Detailed individual case histories were recorded. All patients underwent thorough physical examination, a resting 12-lead electrocardiogram, a cycloergometric test: and 24-hour ambulatory electrocardiographic monitoring. The ergometric test was performed on a mcchanitally braked Monark bicycle ergometer, following our protocol described elsewhere.* All patients underwent a near-maximal test (85% of predicted maximal heart rate according to age) based on progressively increasing intermittent workloads at 5-minute intervals. The initial