The difference of heart rate recovery in ischemic heart disease comparing to normal

Ju, Dong Uk; Kang, Hyun Jae; Kim, Sun Wung; No, Tae Mook; Son, Hyuk Su; Kang, Byung Jun; Kim, Sae Rom; Lee, Bong Ryeol; Jung, Byung Chun; Lee, Jong Joo

Abstract

BACKGROUND: The goal of this study is to evaluate the differences of the rate and the ratio of heart rate changes, which is well known to reflect the vagal reactivation, after peak exercise between ischemic heart disease and normal during treadmill exercise test. Additionally R-wave amplitude changes are evaluated to have the discriminal power between ischemic heart disease and normal.
METHODS
We have studied 253 human (196 control, 57 patients) who took the symptom-limited exercise test using Marquette case 8000 model. The 57 patients who showed the positive result by exercise test have confirmed by coronary angiography. The rate of heart rate changes was defined as the absolute difference of the heart rate subtracted by the just-previous stage heart rate. The ratio of heart rate changes was defined as the percentile of the rate of heart rate changes comparing to the just-previous stage heart rate. The changes of R-wave amplitude at lead V5 and aVF were obtained by the subtraction of R-wave amplitude at the peak exercise stage from that at the standing rest stage respectively. Additively heart rate recovery was defined as the rate of heart rate change which was obtained at 1 minute later after peak exercise.
RESULTS
In patients and control, the resting heart rate were 70 +/- 13 bpm and 69 +/- 11 bpm (p>0.05), and the peak heart rate were 136 +/- 22 bpm and 155 +/- 18 bpm respectively (p<0.001). The rate of heart rate changes in patients group were significantly lower than that in control at 1 minute, 3 minute, and 5 minute respectively (p<0.001, p=0.008, p=0.002). The ratio of heart rate changes in patients group were also significantly lower than that in control at 1 minute, 3 minute, and 5 minute respectively (p=0.017, p=0.027, p=0.002). With comparing both groups, the incidences of ventricular ectopy were not different during exercise and recovery stages, and the difference in the changes of R-wave amplitude at lead V5 and aVF were not observed respectively.
CONCLUSION
The rate and ratio of heart rate changes are significantly lower in iscemic heart disease than in normal, and these are resulted from the depression of vagal reactivation. These findings are supplemental to make a diagnosis and a arrhythmic risk stratification of ischemic heart disease.