Value of Stress-Recovery Index on Exercise ECG in Detection of High-risk Patients on Exercise Tl-201 Scintigraphy

W e sought to determine the value of a new exercise testing index (Stress-Recovery Index (SRI)) combining information on the amount and kinetics of ST depression in the heart rate domain during exercise and recovery to detect high-risk patients on exercise TI-201 scintigraphy. 122 cases without previous myocardial infaretion underwent symptomlimited treadınili exercise testing and Tl-201 SPECT imaging. At the end of each test, the lead exhibiting the greatest ST depression was selected for fıırther analysis to calculate the SRI. Heart rate and corresponding ST segment values were entered in a formerly-designed computer program to automaticaUy calculate SRI values. SPECT images were divided into 20 segments and the number of segments with redistribution defect (RD) were identifıed per patient. Patients were divided into 2 groups as the low-risk group (RD<5, n=88) and the high-risk group (RD~. n=34). The mean SRI of the 2 groups were 5.5±13 and -19.8±15 mm. beats.min-1, respectively (p<0.0001). Moreover, patients with increased lung uptake and left ventricular dilatation indicating high risk at Tl-20 1 scintigraphy had lower SRI values compared to those without (-22.3±14 vs. -5.5±12 mm. beats.min- 1, p<0.0001; -24.2±13 vs.- 6.1±14 mm.beats.min-1; pKeywords: Stress-recovery index, exercise Tl-201 scintigraphy.