ISCHEMIA AND ABNORMAL DIASTOLIC FUNCTION IN HYPERTROPHIC CARDIOMYOPATHY

用铊-201评价放射性核素诱发的心肌灌注缺损 单光子发射计算机断层扫描（SPECT）在超过2/3国家发展 肥厚型心肌病（HCM）患者，这些异常 可以通过维拉帕米治疗减少（或完全预防）。机制 在HCM运动过程中造成铊缺陷的原因被认为是 是心肌缺血。另一种解释是细胞紊乱 与心肌病相关的肌膜活性阳离子摄取 过程由于摄取锝-99m甲氧基丁基异腈（MIBI）， 不像TI-201那样依赖于活性Na-K ATP酶转运系统， 在10例运动诱导的HCM患者中进行了运动MIBI研究， TL-201缺陷。在分析的50个心肌区域中， 在23/24例（96%）异常和26/26例（96%） (100%）的正常心肌区域。也有100%的一致性， 运动引起的空洞扩张因此，这些数据支持这一概念 HCM中的Tl-201缺陷代表真正的灌注异常， 活性Na-K ATP酶转运系统的根本性紊乱。 HCM中心肌缺血的证据也已被证明， 正电子发射断层扫描（PET）。我们研究了12例有症状的HCM患者 运动TI-201 SPECT显示重度肥大（间隔>20 mm）， 静息PET，使用18F-脱氧葡萄糖（FDG）评估局部心肌 葡萄糖利用率（rMGU）和（15）O-水，以定量局部血液 流量（rMBF）。当相对于rMBF进行评估时，rMGU表现出区域性 7例患者存在异质性，rMGU/rMBF增加 与局部心肌缺血相符这些静止数据是 TL数据支持：在所有7例患者中， 静息时rMGU/rMBF增加可导致可逆性Tl-201灌注缺损 锻炼身体因此，HCM患者rMGU相对于rMBF升高， 代表静息时MI的代谢证据，或 既往缺血发作的后遗症。

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.