BMEYE, Amsterdam, The Netherlands.
Med Biol Eng Comput. 2011 Sep;49(9):1073-81. doi: 10.1007/s11517-011-0810-7. Epub 2011 Jul 23.
The enhanced heart rate and blood pressure soon after awaking increases cardiac oxygen demand, and has been associated with the high incidence of acute myocardial infarction in the morning. The behavior of cardiac oxygen supply is unknown. We hypothesized that oxygen supply decreases in the morning and to that purpose investigated cardiac oxygen demand and oxygen supply at night and after awaking. We compared hypertensive to normotensive subjects and furthermore assessed whether pressures measured non-invasively and intra-arterially give similar results. Aortic pressure was reconstructed from 24-h intra-brachial and simultaneously obtained non-invasive finger pressure in 14 hypertensives and 8 normotensives. Supply was assessed by Diastolic Time Fraction (DTF, ratio of diastolic and heart period), demand by Rate-Pressure Product (RPP, systolic pressure times heart rate, HR) and supply/demand ratio by A(dia)/A(sys), with A(dia) and A(sys) diastolic and systolic areas under the aortic pressure curve. Hypertensives had lower supply by DTF and higher demand by RPP than normotensives during the night. DTF decreased and RPP increased in both groups after awaking. The DTF of hypertensives decreased less becoming similar to the DTF of normotensives in the morning; the RPP remained higher. A(dia)/A(sys) followed the pattern of DTF. Findings from invasively and non-invasively determined pressure were similar. The cardiac oxygen supply/demand ratio in hypertensive patients is lower than in normotensives at night. With a smaller night-day differences, the hypertensives' risk for cardiovascular events may be more evenly spread over the 24 h. This information can be obtained noninvasively.
醒来后心率和血压的迅速升高会增加心脏的氧气需求，这与早晨急性心肌梗死的高发有关。心脏氧气供应的情况尚不清楚。我们假设早晨的氧气供应会减少，因此我们调查了夜间和醒来后的心脏氧气需求和供应。我们比较了高血压患者和正常血压患者，并进一步评估了无创和动脉内测量的压力是否会产生相似的结果。在 14 名高血压患者和 8 名正常血压患者中，我们从 24 小时内的肱动脉内压和同时获得的无创手指压重建了主动脉压。通过舒张时间分数（DTF，舒张期与心动周期的比值）评估供应，通过心率-压力乘积（RPP，收缩压乘以心率，HR）评估需求，通过 A（dia）/A（sys）评估供应/需求比，其中 A（dia）和 A（sys）分别为主动脉压曲线下的舒张期和收缩期面积。与正常血压患者相比，高血压患者夜间的供应通过 DTF 较低，需求通过 RPP 较高。两组患者醒来后 DTF 降低，RPP 增加。高血压患者的 DTF 降低幅度较小，与正常血压患者的 DTF 相似；RPP 仍然较高。A（dia）/A（sys）遵循 DTF 的模式。通过有创和无创方法确定的压力的结果相似。高血压患者的心脏氧供应/需求比在夜间低于正常血压患者。随着夜间和日间差异的减小，高血压患者发生心血管事件的风险可能会更均匀地分布在 24 小时内。这些信息可以通过无创方法获得。
