Comparing maximum rate and sustainability of pacing by mechanical vs. electrical stimulation in the Langendorff-perfused rabbit heart.
Comparing maximum rate and sustainability of pacing by mechanical vs. electrical stimulation in the Langendorff-perfused rabbit heart.
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DOI：
10.1093/europace/euw354
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发表时间：
2016-12
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影响因子：
--
通讯作者：
Kohl P
中科院分区：
文献类型：
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作者：
Quinn TA;Kohl P
机械刺激（MS）是一种容易获得的、非侵入性的起搏方法，用于患者的心脏骤停或心动过缓，但MS在高心率下的益处尚不清楚。我们的目的是评估在正常生理条件下，MS与电刺激（ES）对离体心脏的最大兴奋率和可持续性。以超过固有窦性心律（超速起搏；最低起搏率2.5±0.5 Hz）的速率，将局部MS或ES序列应用于langendorff灌注兔心外膜上相同的左心室中部自由壁部位。刺激率逐渐增加，每次刺激之间有一段正常窦性心律的恢复期。MS序列在刺激部位引起反复的局灶性心室兴奋。MS实现1:1捕获的最大速率低于ES（分别为4.2±0.2 Hz和5.9±0.2 Hz）。在所有可能重复MS的超速起搏速率下，即使ES仍然可能进行相同位置的捕获，但在有限次数的循环后，1:1捕获会可逆地丢失。随着刺激速率的增加，直至捕获丢失的MS循环次数减少。如果散布有ES，则捕获失败的MS数量低于仅捕获MS的数量。在这项研究中，我们证明MS可以维持的最大起搏速率低于离体心脏相同部位的ES，并且与ES相比，MS成功的1:1捕获的可持续性是有限的。MS和ES起搏能力差异的机制目前尚不清楚，这对紧急心律管理可能很重要，因此需要进一步研究。
Mechanical stimulation (MS) represents a readily available, non-invasive means of pacing the asystolic or bradycardic heart in patients, but benefits of MS at higher heart rates are unclear. Our aim was to assess the maximum rate and sustainability of excitation by MS vs. electrical stimulation (ES) in the isolated heart under normal physiological conditions. Trains of local MS or ES at rates exceeding intrinsic sinus rhythm (overdrive pacing; lowest pacing rates 2.5±0.5 Hz) were applied to the same mid-left ventricular free-wall site on the epicardium of Langendorff-perfused rabbit hearts. Stimulation rates were progressively increased, with a recovery period of normal sinus rhythm between each stimulation period. Trains of MS caused repeated focal ventricular excitation from the site of stimulation. The maximum rate at which MS achieved 1:1 capture was lower than during ES (4.2±0.2 vs. 5.9±0.2 Hz, respectively). At all overdrive pacing rates for which repetitive MS was possible, 1:1 capture was reversibly lost after a finite number of cycles, even though same-site capture by ES remained possible. The number of MS cycles until loss of capture decreased with rising stimulation rate. If interspersed with ES, the number of MS to failure of capture was lower than for MS only. In this study, we demonstrate that the maximum pacing rate at which MS can be sustained is lower than that for same-site ES in isolated heart, and that, in contrast to ES, the sustainability of successful 1:1 capture by MS is limited. The mechanism(s) of differences in MS vs. ES pacing ability, potentially important for emergency heart rhythm management, are currently unknown, thus warranting further investigation.