EXERCISE STRESS TESTING UNDERESTIMATES IMPROVEMENTS IN FUNCTIONAL CAPACITY IN PATIENTS ON CARDIAC REHABILITATION PROGRAMMES

Abstract

Stress ECG testing is currently used to assess patient safety and determine functional capacity in patients participating in cardiac rehabilitation programmes. AIM: The aim of this study was to compare changes in functional capacity (FC) noted during routine stress ECG testing (EST) and a 6 minute unrestricted locomotion exercise test around a track (ULT). METHODS: This study examined 10 cardiac patients, mean age 54 ± 7 years, who attended cardiac rehabilitation exercise classes (CR) 3x/wk for a 9 mnth period. All subjects undertook I) EST using the Bruce protocol conducted by the cardiologists on referral to CR, and a ULT around an indoor track. These tests were repeated following 9 mths of CR. RESULTS: Average total time during the EST was 7:0 ± 2:20 seconds. Subjects achieved a peak heart rate (HR) of 135 ± 22 bpm during this test. AT 9 mths the EST time increased to 9:14 ± 2:42 min and peak HR to 150 ± 10 bpm (p < 0.05 pre vs post test; a 32% improvement EST time). In contrast, the distance walked during the ULT increased from 695 ± 61 m, to 1085 ± 175 m; a 64% change in FC (p < 0.05 pre vs post tests). CONCLUSIONS: It appears from the results of this study that EST underestimates the improvement in FC in patients participating in phase III CR programmes. Therefore, it is suggested that all CR patients perform the ULT as a better measure of FC both before and after exercise training.