Elhendy A, van Domburg R T, Bax J J, Nierop P R, Geleijnse M L, Ibrahim M M, Roelandt J R
Department of Cardiology, Cairo University Hospital, Cairo, Egypt.
Heart. 1999 Apr;81(4):398-403. doi: 10.1136/hrt.81.4.398.
To investigate the functional significance of chronotropic incompetence during dobutamine stress echocardiography.
The functional significance of chronotropic incompetence was evaluated during dobutamine stress echocardiography in 512 patients without beta blocker treatment who underwent dobutamine stress echocardiography (up to 40 microg/kg/min) and completed the protocol or reached the target heart rate. Mean (SD) age was 60 (12) years (313 men, 199 women). Chronotropic incompetence was defined as failure to achieve 85% of the maximum exercise heart rate predicted for age and sex (220 - age in men; 200 - age in women) at maximum dobutamine dose.
Chronotropic incompetence occurred in 196 patients (38%). Affected patients were significantly younger, more likely to be men (both p << 0.001) and smokers (p < 0.05), had a higher prevalence of previous myocardial infarction (p < 0.005) and resting wall motion abnormalities (p < 0. 05), and had a lower resting heart rate (p << 0.001) and systolic blood pressure (p << 0.001) than patients without chronotropic incompetence, but there was no difference in the overall prevalence of ischaemia and significant coronary artery disease. By multivariate analysis, independent predictors of chronotropic incompetence were a lower resting heart rate (p << 0.001), younger age (p << 0.001), and male sex (p << 0.001).
The relations among sex, age, and chronotropic incompetence show the need to titrate the dobutamine dose using specific data based on age and sex related heart rate responses to dobutamine rather than to an exercise stress test. Obtaining specific heart rate criteria is necessary to determine whether chronotropic incompetence represents a real failure to achieve a normal response or is the result of applying an inappropriate gold standard.
探讨多巴酚丁胺负荷超声心动图检查时变时性功能不全的功能意义。
对512例未接受β受体阻滞剂治疗且接受多巴酚丁胺负荷超声心动图检查（剂量高达40μg/kg/min）并完成检查方案或达到目标心率的患者，评估时变时性功能不全的功能意义。平均（标准差）年龄为60（12）岁（男性313例，女性199例）。时变时性功能不全定义为在最大多巴酚丁胺剂量时未能达到根据年龄和性别预测的最大运动心率的85%（男性为220减去年龄；女性为200减去年龄）。
196例患者（38%）出现时变时性功能不全。与未出现时变时性功能不全的患者相比，受影响的患者明显更年轻，男性比例更高（均p << 0.001）且吸烟者比例更高（p < 0.05），既往心肌梗死患病率更高（p < 0.005）以及静息壁运动异常患病率更高（p < 0.05），静息心率更低（p << 0.001）和收缩压更低（p << 0.001），但缺血和显著冠状动脉疾病的总体患病率无差异。多因素分析显示，时变时性功能不全的独立预测因素为静息心率更低（p << 0.001）、年龄更小（p << 0.001）和男性（p << 0.001）。
性别、年龄与时变时性功能不全之间的关系表明，需要根据基于年龄和性别对多巴酚丁胺的心率反应的特定数据来滴定多巴酚丁胺剂量，而不是根据运动负荷试验。获取特定的心率标准对于确定时变时性功能不全是代表真正未能达到正常反应还是应用不适当的金标准的结果是必要的。
