Incidence of ventricular arrhythmias during silent myocardial ischaemia in coronary artery disease.

This study investigated the relationship between silent myocardial ischaemia during daily life and ventricular ectopic activity in patients with angiographically confirmed coronary artery disease and preserved left ventricular function. We studied 45 patients (37 men, 8 women, aged 42-70 years) who satisfied the above criteria. All underwent 72-h continuous electrocardiographic monitoring for the detection of silent ischaemic episodes and ventricular arrhythmias. A total of 225 ischaemic episodes were recorded, of which 198 (88%) were silent. Fourteen of the silent episodes (7.1%) were associated with ventricular arrhythmias. There was no statistically significant relationship between the association of silent ischaemia with arrhythmias and the patients' exercise test or angiography findings. However, the ventricular arrhythmias tended to be associated with ischaemic episodes of longer duration and with greater maximum ST-segment depression. Silent myocardial ischaemia during everyday activity is accompanied by ventricular ectopic activity in only a small percentage of cases. The association between ischaemia and ventricular arrhythmias seems to have more to do with the duration of the ischaemic episode and the degree of ST segment depression than with the severity of the underlying coronary artery disease.