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ȣ - 500767 113 |
| Evaluation of Chronotropic Competence during Treadmill Exercise Test is Useful? |
| 전남대학교병원 순환기내과 |
| 윤남식, 조정관, 박형욱, 이상록, 정대호, 황선호, 홍서나, 김계훈, 김주한, 안영근, 정명호, 박종춘, 강정채 |
Background: There are few reports about chronotropic incompetence in Korea. The goal of this study is to identify the prevalence of chronotropic incompetence and its determinants and clinical outcome. Method: Chronotropic incompetence was defined as failure to achieve 85% of the maximal age-predicted heart rate(HR-Mx) during treadmill exercise test. Patients who could not achieve the 4th stage or whose baseline ECG was not sinus rhythm were excluded. We reviewed 133 consecutive patients(Group I, 55.8±10.0 year-old, male:female=87:46) who had chronotropic incompetence. For control-group, 722 consecutive patients(Group II, 53.1±12.3 year-old, male:female =418 : 304) were analyzed. Result: No difference of sex and age was noted. The prevalence of chronotropic incompetence was 15.5%. The prevalence of hypertension and hyperlipidemia was high in Group I(50.0% vs. 28.6%, p<0.001; 22.2% vs. 0%, p<0.001). Underlying heart disease was more common in group I(p<0.001). There was no association between underlying disease entity and severity of chronotropic incompetence(p>0.05). Baseline heart rate(73.6±10.6/min vs. 83.9±14.0/min), exercise induced peak heart rate(HR-Ex)(127.6±11.5/min vs. 159.7±20.1/min), HR-Ex/HR-Mx(0.77±0.05 vs. 0.95±0.10), and heart rate reserve(HRR)(0.59±0.10 vs. 0.92±0.22) were lower in group I(p<0.05). In group I, severity of chronotropic incompetence was higher in beta-blocker user(HR-Ex/HR-Mx=0.75±0.06 vs. 0.78±0.05, p=0.001; HRR=0.55±0.12 vs. 0.60± 0.09, p=0.006). Calcium channel blocker and Angiotensin converting enzyme inhibitor had no influence to chronotropic incompetence(p>0.05). Severity of chronotropic incompetence was lower in statin users(HR-Ex/HR-Mx=0.79±0.04 vs. 0.77±0.06, p=0.049; HRR=0.61±0.08 vs. 0.58±0.11, p=0.044). No mortality difference was identified between groups in 6 months. Conclusion: The prevalence of chronotropic incompetence was 15.5%. There is no association between underlying disease entity and severity of chronotropic incompetence. Statin seems to lower chronotropic incometence. Unstable angina pectoris develops ,more commonly, in patients with poor chronotropic competence. Chronotropic incompetence could not predict 6 month clinical outcome.
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