Saumarez R C, Slade A K, Grace A A, Sadoul N, Camm A J, McKenna W J
Department of Cardiological Sciences, St George's Hospital Medical School, London, UK.
Circulation. 1995 Jun 1;91(11):2762-8. doi: 10.1161/01.cir.91.11.2762.
Increased duration of paced right ventricular (RV) electrograms in hypertrophic cardiomyopathy has been shown in 37 patients to correlate with the risk of ventricular fibrillation (VF). The changes in electrogram duration with pacing stimulus prematurity discriminated patients into three groups: VF survivors, an intermediate group with either non-sustained ventricular tachycardia (NSVT) on ambulatory monitoring or a family history of sudden death (FHSD), and those with none of these risk factors (noRF) for sudden death (SD). The consistency of these original groups has been tested prospectively in a further 64 patients.
Of 64 patients with hypertrophic cardiomyopathy, 3 had documented VF, 1 had witnessed SD and is assumed to have had VF, 25 had NSVT, 21 had FHSD, and 14 had noRF. Nineteen patients had syncope. They were studied by pacing one RV site with a decremental sequence and recording high-pass filtered electrograms from three other RV sites. The delay of each fractionated potential in the electrogram was determined relative to a pacing stimulus of increasing prematurity. These measurements were repeated by pacing each ventricular site in turn. The electrograms were characterized by two parameters: the extrastimulus coupling interval (S1S2) at which delay increased by more than 0.75 ms/20 ms decrease in S1S2 interval and the change in electrogram duration between an S1S2 of 350 ms and ventricular effective refractory period. The 4 VF patients had a mean increase in electrogram duration of 16.1 ms and an increase in delay at a mean S1S2 of 368 ms. Three VF patients were within the original VF group, while only 6 of 60 non-VF patients were within this group, discriminating between VF patients and the remainder (P < .007). The 14 noRF patients had a mean change in electrogram duration of 4.5 ms and an increase in delay at a mean S1S2 of 301 ms. Eleven patients were within the original noRF group, and only 8 of the remaining 50 patients also were within the noRF group, discriminating between the noRF patients and the remainder (P < .0005). Most of the NSVT and FHSD patients were between the original VF and noRF groups, with 5 of 25 NSVT and 1 of 31 FHSD patients in the original VF group. There was no relation between syncope and electrophysiological characteristics. Programmed electrical stimulation (PES) was performed in the first 15 patients of this study. Of the total 52 patients from the original and current studies, PES identified 2 out of 6 VF patients, and there was no correlation between VF inducibility and intraventricular conduction delay.
These data are consistent with the original VF and noRF groups. Most patients with FHSD or NSVT were between these groups. Pooled data from the original and current groups (n = 101) allow definition of a new VF group, which includes all patients with VF (n = 9), 8 of 30 patients with VT, and 3 of 31 patients with FHSD. This new group may be used as a criterion for implantable cardioverter-defibrillator implantation in a prospective trial of the technique for the prediction of SD.
在37例肥厚型心肌病患者中已表明，右心室（RV）起搏心电图持续时间延长与室颤（VF）风险相关。根据起搏刺激提前程度时心电图持续时间的变化，将患者分为三组：VF存活者、动态监测有非持续性室性心动过速（NSVT）或有猝死家族史（FHSD）的中间组，以及无这些猝死（SD）危险因素（无RF）的患者。已在另外64例患者中对这些原始分组的一致性进行了前瞻性测试。
64例肥厚型心肌病患者中，3例记录到VF，1例有目击的SD且推测发生了VF，25例有NSVT，21例有FHSD，14例无RF。19例患者有晕厥。通过以递减序列起搏一个RV部位并记录来自其他三个RV部位的高通滤波心电图对他们进行研究。相对于提前程度增加的起搏刺激，确定心电图中每个碎裂电位的延迟。依次对每个心室部位进行起搏，重复这些测量。心电图由两个参数表征：额外刺激耦合间期（S1S2），在此间期S1S2每减少20 ms延迟增加超过0.75 ms；以及S1S2为350 ms与心室有效不应期之间的心电图持续时间变化。4例VF患者的心电图持续时间平均增加16.1 ms，在平均S1S2为368 ms时延迟增加。3例VF患者在原始VF组内，而60例非VF患者中只有6例在该组内，可区分VF患者与其余患者（P <.007）。14例无RF患者的心电图持续时间平均变化为4.5 ms，在平均S1S2为301 ms时延迟增加。11例患者在原始无RF组内，其余50例患者中只有8例也在无RF组内，可区分无RF患者与其余患者（P <.0005）。大多数NSVT和FHSD患者介于原始VF组和无RF组之间，25例NSVT患者中有5例、31例FHSD患者中有1例在原始VF组内。晕厥与电生理特征之间无关联。在本研究的前15例患者中进行了程控电刺激（PES）。在原始研究和当前研究的总共52例患者中，PES在6例VF患者中识别出2例，VF诱发性与室内传导延迟之间无相关性。
这些数据与原始VF组和无RF组一致。大多数FHSD或NSVT患者介于这两组之间。来自原始组和当前组（n = 101）的汇总数据允许定义一个新的VF组，其中包括所有VF患者（n = 9）、30例VT患者中的8例以及31例FHSD患者中的3例。这个新组可在前瞻性的SD预测技术试验中用作植入式心脏复律除颤器植入的标准。
