Prognosis and management of occult coronary artery disease

Abstract

Ischaemic episodes during daily activities are frequent in patients with coronary artery disease [1–8]. These episodes, detected by ambulatory electrocardiographic monitoring which are mostly silent, last from a few minutes up to several hours. Treatment of patients with silent ischaemic episodes is justified only if silent ischaemia represents similar degree of ischaemia, as symptomatic one. Levy and coworkers [9] studied 19 patients with coronary artery disease who had 67 ischaemia episodes. During the 35 painful episodes the pulmonary artery diastolic pressure increased in 34, while during the 32 silent episodes it increased in 30 patients. Thus, silent and symptomatic episodes were associated with similar haemodynamic changes. In our study of 191 patients with coronary artery disease [10], patients with silent episodes had the same extent of coronary disease as patients with symptomatic episodes. The average duration of the silent episodes (15 minutes) was similar to that of the symptomatic ones (14 minutes), the heart at onset at the ischaemia was similar (94/min vs. 96/min) as well as the maximal ST depression (2.0 mm vs 2.1 mm). Similar findings were reported by von Arnim [11]. Deanfield and coworkers [12] found that the heart rate of onset of ST depression was similar during the silent and symptomatic episodes, but the symptomatic episodes were slightly longer (by a mean of 13%) than those without pain. Hirzel and coworkers [13] performed haemodynamic measurements during exercise in 36 patients with coronary artery disease. The left ventricular end diastolic pressure increased from 18 to 36 mmHg in the group with silent ischaemia during exercise and from 13 to 29 mmHg in the symptomatic group (p=NS). The left ventricular ejection fraction decreased from 59% to 50% in the silent group and from 60% to 52% in the symptomatic group (p=NS). Davies and coworkers [14] found in patients with angina at rest that transient asymptomatic ST segment shifts are consistently associated with large changes in left ventricular volume, similar to those observed during painful episodes. Wohlgelernter et al. [15] reported that during balloon angioplasty, echocardiographic measurements of global and regional left ventricular dysfunction were comparable in patients who were symptomatic or asymptomatic during the balloon inflations. These studies suggest that silent and symptomatic ischaemic episodes represent the same degree of myocardial ischaemia, and that patients with silent ischaemia have the same extent of coronary disease, as patients with painful ischaemia.KeywordsUnstable AnginaSilent Myocardial IschaemiaSilent IschaemiaSymptomatic EpisodeIschaemic EpisodeThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.