USEFULNESS OF A QUANTITATIVE-ANALYSIS OF THE RECOVERY PHASE PATTERNS OF THE ST-SEGMENT DEPRESSION IN THE DIAGNOSIS OF CORONARY-ARTERY DISEASE

PURPOSE: TO assess the diagnostic value of the recovery phase patterns of the ST-segment depression in patients referred for chest pain. PAT IENTS AND METHODS: Continuous plots of ST-segment depression against h eart rate during exercise and recovery were constructed within a popul ation of 160 consecutive symptomatic patients who all had undergone ca theterization (80 with greater than or equal to 1 stenosis greater tha n or equal to 50%). We used a new quantitative method of measurement a llowing all kinds of rate recovery loops (even the so-called ''interme diate'' loops) to be considered for analysis. The measurements of the heart rate (HR)-adjusted ST-segment depression were performed at 20 an d 60 ms from the J point, providing two different values of a quantifi ed recovery loop index (RLI): RLI 20 and RLI 60. RESULTS: Both RLI sho wed a higher specificity (0.81 +/- 0.04 and 0.74 +/- 0.05, respectivel y) than did the standard criterion (0.65 +/- 0.10), but the difference was significant regarding RLI 20 only (P = 0.011). As to the sensitiv ity, no significant differences were found among all of the criteria ( 0.74 +/- 0.05, 0.80 +/- 0.04, 0.76 +/- 0.05, respectively). The timing of measurements of the RLI within the repolarization phase did not af fect their overall accuracy (0.77 +/- 0.03 for both RLI). The values o f the receiver-operating characteristic (ROC) curve areas were signifi cantly greater for both RLI (0.83 +/- 0.06 and 0.84 +/- 0.06 respectiv ely) than for the standard criterion (0.75 +/- 0.07; P < 0.02). Finall y, both RLI allowed to differentiate accurately the study subjects acc ording to the number of diseased vessels, whereas the standard criteri on could only distinguish between CAD patients and subjects with norma l angiograms. CONCLUSION: The quantitative analysis of the rate recove ry phase patterns appears to be useful for the diagnosis of coronary h eart disease and the assessment of its severity in symptomatic patient s. (C) 1996 by Excerpta Medica, Inc.