Assessment of the functional significance of coronary artery disease with atrial pacing and cardiokymography

Thirty-six patients were studied during the course of cardiac catheterization to assess the role of cardiokymography and atrial pacing in the functional evaluation of angiographic coronary arterial stenosis. Only 4 of 25 patients with greater than 50 percent diameter stenosis of at least one major vessel had 0.1 mv or greater S-T segment depression at a paced heart rate of 123 ± 25/min, and 2 of 11 normal patients revealed a similar response (P = not significant). In contrast, in 22 of 25 patients systolic outward motion developed as determined with cardiokymography during the same pacing period, whereas in only 1 of 11 normal patients a similar abnormality did develop (P < 0.001). The threshold heart rate for abnormal wall motion preceded that for S-T depression, in each case by an average of 36 ± 8 beats/min. These data are consistent with the view that regional wall motion abnormalities are highly sensitive and specific markers of ischemia and that such abnormalities may be detected noninvasively with cardiokymography. It is concluded that atrial pacing in conjunction with cardiokymography is applicable to the functional assessment of ischemic heart disease and may provide a means for objective evaluation of the significance of angiographically observed coronary stenosis.