Peripheral arterial tonometry: a diagnostic method for detection of myocardial ischemia induced during mental stress...

Mental stress testing is considered a reliable method for diagnosing patients with coronary heart disease (CHD) who may be at risk for future events. It has been shown recently that myocardial ischemia induced during mental stress tests is specifically associated with peripheral arterial vasoconstriction.

The study was undertaken to test the diagnostic capability of peripheral arterial tonometry (PAT) to detect peripheral arterial vasomotor changes.

We monitored pulsatile finger blood volume changes using a specially designed finger plethysmograph, PAT that can detect peripheral arterial vasomotor changes. Equilibrium radionuclide angiography (ERNA) was simultaneously performed in 18 male patients at rest and during a mental arithmetic stress test with harassment. All patients had previously diagnosed coronary disease and positive exercise tests. Myocardial ischemia was diagnosed by ERNA when global ejection fraction fell > or = 8% during mental stress or new (or worsened) focal wall motion abnormalities occurred. Peripheral arterial tonometry tracings were considered abnormal when the pulse wave amplitude decreased by > or = 20% from baseline.

In 18 patients there were 16 usable studies. In eight patients, both ERNA and PAT were abnormal, and in six patients the tests were negative by both methods. In two cases, the results were discordant. Therefore, when considering an abnormal PAT tracing as indicative of mental stress-driven myocardial ischemia, concordance of the two methods was 88%.

The use of PAT may facilitate both clinical testing and research during mental stress.