목적 : 고혈압 환자에서 대동맥 경직도의 증가는 심 혈관 질환의 위험도를 반영하는 독립적인 위험인자로, 혈압의 상승이나 교감신경계의 항진은 대동맥의 경직도 를 증가시킨다. 그러나 인공심박기에 의한 심박수의 상 승은 대동맥의 경직도를 증가시키지 않는 것이 보고되 고 있다. 본 연구에서는 고혈압 환자에서 교감신경계 흥 분제인 isoproterenol을 투여하여 심박수를 상승시켰을 때 대동맥 경직도의 변화를 연구하였다. 방법 : 고혈압 환자를 대상으로 하였으며, 연구 3일 전에 모든 심혈관계 약제를 중단하였다. Isoproterenol을 점적 정주하며 심박수가 분당 5∼10회 증가할 때 마다, 심박수와 혈압을 측정하며, 좌측 경동맥에서 좌측 대퇴 동맥까지의 맥파전파속도를 foot-to-foot method로 측 정하고, 탄성도와 탄성지수를 계산하였다. 심박수, 맥파 전파속도, 탄성도 그리고 탄성지수는 기저 값에서 변화 한 값을 기저 값에서의 백분율로 계산하여 분석하였다. 결과 : 총 17명의 고혈압 환자(평균연령: 59±9세)에 서 연구가 이루어졌다. 기저 심박수에서 10% 증가할 때 마다, 군으로 분류하여 분석한 결과 맥파전파속도, 탄성 도 그리고 탄성지수의 변화는 각 군간에 통계적으로 유 의한 차이를 보이지 않았다(p>0.05). 맥파전파속도, 탄 성도 그리고 탄성지수의 변화를 심박수의 변화에 대한 단순 회귀분석에서, 맥파전파속도의 변화와 탄성도의 변 화는 심박수 증가에 대하여 통계적으로 유의한 상관관 계를 보여주지 않았다(p>0.05). 탄성지수의 변화는 심박 수의 변화에 대하여 미약한 음의 상관관계를 보였으나 (r=0.215, p<0.05), 낮은 r2(0.046)값을 보였다..

Background : Increased aortic stiffness (AS) is an independent risk factor of cardiovascular disease in patients with hypertension. Elevation of blood pressure (BP) or sympathetic tone increases AS. It was reported that acute changes in heart rate by artificial pacemaker did not affect AS. However, it is unknown whether changes in HR by sympathomimetics can affect AS in patients with hypertension. We investigated the effect of changes of HR by isoproterenol (ISO) on AS in 17 hypertensives (mean age: 59±9 years). Methods : All vasoactive drugs were discontinued at least 3 days before the study. Carotid-to-femoral pulse wave velocity (PWV) was measured by foot-to-foot method. Pulse wave recordings were done at baseline and at every increase of HR by 5 to 10 bpm with gradual increase of dose of ISO. BPs were measured simultaneously by the fluid-filled manometer system through the side arm of arterial sheath of femoral artery. HR was measured by electrocardiography. Compliance (C) and compliance index (Ci) were calculated from PWV, pulse pressure, systolic and diastolic blood pressure by established formulas. For analysis, HR, PWV, C and Ci were converted as percent changes (Δ) from the baseline values. Percent changes of parameters of AS, i.e., ΔPWV, ΔC, and ΔCi, were grouped by every 10% increase in HR. Results : There was no significant difference among groups in ΔPWV, ΔC and ΔCi (p>0.05 for each). With simple regression analysis, ΔPWV and ΔC showed no significant correlation with ΔHR (r=0.18, 0.13 respectively, p>0.05 for each). ΔCi was weakly correlated with ΔHR (r=0.22, p<0.05). However, only 4.6% of ΔCi could be referable to ΔHR (r2=0.046). Conclusion : AS was not affected by changes in heart rate by isoproterenol, suggesting that it is not necessary to consider changes of HR when measuring aortic PWV.(Korean J Med 64:28-33, 2003)

Background : Increased aortic stiffness (AS) is an independent risk factor of cardiovascular disease in patients with hypertension. Elevation of blood pressure (BP) or sympathetic tone increases AS. It was reported that acute changes in heart rate by artificial pacemaker did not affect AS. However, it is unknown whether changes in HR by sympathomimetics can affect AS in patients with hypertension. We investigated the effect of changes of HR by isoproterenol (ISO) on AS in 17 hypertensives (mean age: 59±9 years). Methods : All vasoactive drugs were discontinued at least 3 days before the study. Carotid-to-femoral pulse wave velocity (PWV) was measured by foot-to-foot method. Pulse wave recordings were done at baseline and at every increase of HR by 5 to 10 bpm with gradual increase of dose of ISO. BPs were measured simultaneously by the fluid-filled manometer system through the side arm of arterial sheath of femoral artery. HR was measured by electrocardiography. Compliance (C) and compliance index (Ci) were calculated from PWV, pulse pressure, systolic and diastolic blood pressure by established formulas. For analysis, HR, PWV, C and Ci were converted as percent changes (Δ) from the baseline values. Percent changes of parameters of AS, i.e., ΔPWV, ΔC, and ΔCi, were grouped by every 10% increase in HR. Results : There was no significant difference among groups in ΔPWV, ΔC and ΔCi (p>0.05 for each). With simple regression analysis, ΔPWV and ΔC showed no significant correlation with ΔHR (r=0.18, 0.13 respectively, p>0.05 for each). ΔCi was weakly correlated with ΔHR (r=0.22, p<0.05). However, only 4.6% of ΔCi could be referable to ΔHR (r2=0.046). Conclusion : AS was not affected by changes in heart rate by isoproterenol, suggesting that it is not necessary to consider changes of HR when measuring aortic PWV.(Korean J Med 64:28-33, 2003)

Aorta; Heart rate; Hypertension