ISCHEMIA AND ABNORMAL DIASTOLIC FUNCTION IN HYPERTROPHIC CARDIOMYOPATHY

~(201)Tl评价运动性心肌灌注损伤 单光子发射计算机断层扫描(SPECT)在超过三分之二的 肥厚型心肌病(HCM)患者，以及这些异常 可通过维拉帕米治疗减少(或完全预防)。这一机制 对肥胖症患者运动中的铊缺陷负有责任的假设是 是心肌缺血。另一种解释是细胞紊乱 跨肌膜活性阳离子摄取与心肌病相关 进程。由于99M甲氧基丁基异腈(MIBI)的摄取 不像TI-201那样依赖于活性的Na-K ATPase转运系统，我们 10例运动诱发肥厚性心肌病患者的运动MIBI研究 Tl-201缺陷。在分析的50个心肌区域中，有 异常23/24(96%)和26/26的TL-201与MIBI摄取的符合率 (100%)正常心肌区。还有100%的符合率 运动性空洞扩张。因此，这些数据支持这一概念 HCM的TL-201缺陷代表真正的血流灌注异常，而不是 活性Na-K-ATPase转运系统的基本干扰。 肥厚性心肌病心肌缺血的证据也已被证实 正电子发射断层扫描(PET)。我们研究了12名有症状的肥厚型心肌病患者。 运动TI-201SPECT显示重度肥厚(室间隔<20 mm) 静息正电子发射计算机断层扫描18F-脱氧葡萄糖(FDG)评价局部心肌 葡萄糖利用率(RMGU)和(15)O-水用于区域血液的定量 流量(RMBF)。当相对于rMBF进行评估时，rMGU表现为地区性 7例患者存在异质性，rMGU/rMBF升高 与局部心肌缺血相容。这些静态数据是 TL数据支持：在所有7名患者中，相同的区域 静息rMGU/rMBF增加导致可逆性TL-201灌注缺陷 通过锻炼。因此，肥厚性心肌病患者rMGU相对于rMBF升高 代表静息状态下心肌梗死的代谢证据或代谢 先前缺血发作的后遗症。

Exercise-induced myocardial perfusion defects as assessed by thallium-201 single photon emission computed tomography (SPECT) develop in over 2/3 of patients with hypertrophic cardiomyopathy (HCM), and these abnormalities may be reduced (or prevented entirely) by verapamil therapy. The mechanism responsible for thallium defects during exercise in HCM has been assumed to be myocardial ischemia. An alternative explanation is disturbed cellular active cation uptake across the sarcolemma related to the cardiomyopathic process. Since uptake of technetium-99m methoxybutyl isonitrile (MIBI) is not dependent on the active Na-K ATPase transport system, as is TI-201, we performed exercise MIBI studies in 10 HCM patients with exercise-induced Tl-201 defects. Of the 50 myocardial regions analyzed, there was concordance of Tl-201 and MIBI uptake in 23/24 (96%) of abnormal and 26/26 (100%) of normal myocardial regions. There was also 100% concordance of exercise-induced cavity dilatation. Thus, these data support the concept that Tl-201 defects in HCM represent true perfusion abnormalities and not a fundamental disturbance of the active Na-K ATPase transport system. Evidence of myocardial ischemia in HCM has also been demonstrated using positron emission tomography (PET). We studied 12 symptomatic HCM patients with severe hypertrophy (septum >20 mm) by exercise TI-201 SPECT and resting PET, using 18F-deoxyglucose (FDG) to assess regional myocardial glucose utilization (rMGU) and (15)O-water to quantitate regional blood flow (rMBF). When assessed relative to rMBF, rMGU demonstrated regional heterogeneity in 7 patients, with a pattern of increased rMGU/rMBF compatible with regional myocardial ischemia. These data at rest were supported by the TL data: in all 7 patients, the same regions with increased rMGU/rMBF at rest developed reversible Tl-201 perfusion defects with exercise. Thus, elevated rMGU relative to rMBF in patients with HCM represents either metabolic evidence of MI at rest or the metabolic sequelae of prior ischemic episodes.