Uebing Anselm, Diller Gerhard-Paul, Li Wei, Maskell Mark, Dimopoulos Konstantinos, Gatzoulis Michael A
Adult Congenital Heart Centre, Royal Brompton Hospital and the National Heart and Lung Institute at Imperial College, London, United Kingdom.
Cardiol Young. 2010 Oct;20(5):485-94. doi: 10.1017/S1047951110000454. Epub 2010 May 11.
Inappropriate heart rate response to exercise - chronotropic incompetence - and exercise intolerance are common in patients with a systemic right ventricle. We aimed to assess the relationship between heart rate increase, oxygen consumption, and timing of the right ventricular cardiac cycle in this cohort.
We prospectively studied nine patients with systemic right ventricles and pre-existing pacemakers using Doppler-echocardiography and treadmill exercise testing. Echocardiography was performed at increasing heart rates. Exercise tests were performed with baseline pacemaker settings and with optimised heart rate response in random order. In addition, eight age- and gender-matched controls underwent exercise testing using a similar exercise protocol.
Patients with a systemic right ventricle had significantly lower peak oxygen consumption compared to controls - 12.6 plus or minus 6.8 versus 31.4 plus or minus 6.6 metres per kilogram per minute (p = 0.0006) - at baseline and active pacemaker reprogramming failed to increase peak oxygen consumption in this cohort - 12.6 plus or minus 6.8 versus 12.4 plus or minus 4.9 millilitres per kilogram per minute (p = NS) at baseline and with reprogramming, respectively. We found not only a marked increase in total isovolumic time but also a significant reduction in total filling time and the aortic velocity time integral, p-value is less than 0.001 for all, at higher heart rates compared to baseline conditions.
This study suggests that despite chronotropic incompetence at baseline, rate-responsive pacing does not improve exercise capacity in patients with a systemic right ventricle. It further indicates that high heart rates may be detrimental in these patients by reducing diastolic filling and stroke volume. These findings may have clinical implications when considering implantation of a permanent pacemaker in this cohort.
对于系统性右心室患者，运动时心率反应异常（变时性功能不全）和运动不耐受很常见。我们旨在评估该队列中心率增加、耗氧量与右心室心动周期时间之间的关系。
我们前瞻性地研究了9例患有系统性右心室且已植入起搏器的患者，采用多普勒超声心动图和跑步机运动试验。在心率增加时进行超声心动图检查。运动试验按随机顺序在基线起搏器设置和优化心率反应的情况下进行。此外，8名年龄和性别匹配的对照者采用类似的运动方案进行运动试验。
与对照组相比，系统性右心室患者在基线时的峰值耗氧量显著更低——分别为12.6±6.8与31.4±6.6米/千克/分钟（p = 0.0006）——并且在该队列中，主动重新编程起搏器未能增加峰值耗氧量——基线时和重新编程后分别为12.6±6.8与12.4±4.9毫升/千克/分钟（p =无显著性差异）。我们发现，与基线条件相比，在较高心率时，不仅总等容时间显著增加，而且总充盈时间和主动脉速度时间积分也显著减少，所有p值均小于0.001。
本研究表明，尽管基线时存在变时性功能不全，但频率应答性起搏并不能改善系统性右心室患者的运动能力。这进一步表明，高心率可能会通过减少舒张期充盈和每搏输出量而对这些患者有害。在考虑为该队列患者植入永久性起搏器时，这些发现可能具有临床意义。
