Weindling S N, Wernovsky G, Colan S D, Parker J A, Boutin C, Mone S M, Costello J, Castañeda A R, Treves S T
Department of Cardiology, Children's Hospital, Division of Nuclear Medicine, Boston, Massachusetts 02115.
J Am Coll Cardiol. 1994 Feb;23(2):424-33. doi: 10.1016/0735-1097(94)90430-8.
This study was conducted to determine the prevalence of myocardial perfusion abnormalities at rest and exercise and to assess exercise capacity in children after the arterial switch operation.
There have been sporadic reports of myocardial ischemia or sudden death in children after the arterial switch operation for transposition of the great arteries, possibly related to inadequate coronary perfusion due to kinking or stenosis of the translocated coronary arteries.
Myocardial perfusion at rest and peak exercise was assessed using the scintigraphic agent technetium-99m methoxyisobutyl isonitrile (sestamibi). Exercise capacity was determined with a modified Bruce protocol. Ambulatory electrocardiographic (ECG) Holter monitoring was performed. Ventricular function, contractility and wall motion were assessed echocardiographically.
Twenty-three children (aged 4.2 to 7.9 years) underwent evaluation. Abnormalities were found on the rest perfusion scans in 22 children (95.6%). The left ventricular myocardium was divided into 13 segments for analysis. Of 299 rest segments, 225 (75.3%) were normal, 11 (3.7%) showed mild defects, 45 (15%) moderate defects and 18 (6%) severe defects at rest. At peak exercise, 237 segments (79.3%) were normal, 24 (8%) showed mild defects, 33 (11%) moderate defects and 5 (1.7%) severe defects. Compared with rest studies, myocardial perfusion grade at exercise was unchanged in 246 segments (82.3%), improved in 42 (14%) and worsened in 11 (3.7%). All patients had normal exercise tolerance without symptoms or ischemic ECG changes. No ventricular tachycardia was seen on Holter monitoring. All patients had a shortening fraction > or = 27%. Left ventricular contractility was normal in 12 children in whom it was assessed. Regional wall motion was normal in 17 children with adequate echocardiographic images for this analysis.
Myocardial perfusion scan abnormalities assessed by technetium-99m sestamibi are common after an arterial switch operation. These abnormalities are of uncertain clinical significance and generally lessen with exercise. The normal exercise tolerance without symptoms or ECG changes suggests that myocardial perfusion is adequate during the physiologic stress of exercise in children up to 8 years after an arterial switch operation.
本研究旨在确定大动脉调转术患儿静息及运动时心肌灌注异常的发生率，并评估其运动能力。
对于大动脉转位行大动脉调转术的患儿，曾有散在报道发生心肌缺血或猝死，可能与冠状动脉移位导致扭结或狭窄引起的冠状动脉灌注不足有关。
使用放射性核素显像剂锝-99m甲氧基异丁基异腈（sestamibi）评估静息及运动高峰时的心肌灌注。采用改良的布鲁斯方案测定运动能力。进行动态心电图（ECG）Holter监测。通过超声心动图评估心室功能、收缩性及室壁运动。
23名儿童（年龄4.2至7.9岁）接受了评估。22名儿童（95.6%）静息灌注扫描发现异常。左心室心肌分为13个节段进行分析。在299个静息节段中，225个（75.3%）正常，11个（3.7%）显示轻度缺损，45个（15%）中度缺损，18个（6%）重度缺损。在运动高峰时，237个节段（79.3%）正常，24个（8%）显示轻度缺损，33个（11%）中度缺损，5个（1.7%）重度缺损。与静息研究相比，246个节段（82.3%）运动时心肌灌注分级未变，42个（14%）改善，11个（3.7%）恶化。所有患者运动耐量正常，无症状或缺血性ECG改变。Holter监测未见室性心动过速。所有患者的缩短分数≥27%。12名接受评估的儿童左心室收缩性正常对17名有足够超声心动图图像进行此分析的儿童，节段性室壁运动正常。
锝-99m sestamibi评估的心肌灌注扫描异常在大动脉调转术后很常见。这些异常的临床意义尚不确定，且一般在运动时减轻。运动耐量正常，无症状或ECG改变表明，大动脉调转术后8岁以下儿童在运动的生理应激期间心肌灌注充足。
