Institute of Cardiovascular Science (R.K.H., J.B.A., K.K., R.D., H.S., A.S., G.J., L.R.L., W.J.M., G.C., J.C.M.), University College London, United Kingdom.
Barts Heart Centre, The Cardiovascular Magnetic Resonance Imaging Unit and The Inherited Cardiovascular Diseases Unit, St Bartholomew's Hospital, West Smithfield, London, United Kingdom (R.K.H., J.B.A., K.K., R.D., H.S., A.S., J.W.M., G.J., S.M., L.R.L., J.C.M.).
Circ Cardiovasc Imaging. 2023 Mar;16(3):e014907. doi: 10.1161/CIRCIMAGING.122.014907. Epub 2023 Mar 21.
Apical hypertrophic cardiomyopathy (ApHCM) accounts for ≈10% of hypertrophic cardiomyopathy cases and is characterized by apical hypertrophy, apical cavity obliteration, and tall ECG R waves with ischemic-looking deep T-wave inversion. These may be present even with <15 mm apical hypertrophy (relative ApHCM). Microvascular dysfunction is well described in hypertrophic cardiomyopathy. We hypothesized that apical perfusion defects would be common in ApHCM.
A 2-center study using cardiovascular magnetic resonance short- and long-axis quantitative adenosine vasodilator stress perfusion mapping. One hundred patients with ApHCM (68 overt hypertrophy [≥15 mm] and 32 relative ApHCM) were compared with 50 patients with asymmetrical septal hypertrophy hypertrophic cardiomyopathy and 40 healthy volunteer controls. Perfusion was assessed visually and quantitatively as myocardial blood flow and myocardial perfusion reserve.
Apical perfusion defects were present in all overt ApHCM patients (100%), all relative ApHCM patients (100%), 36% of asymmetrical septal hypertrophy hypertrophic cardiomyopathy, and 0% of healthy volunteers (<0.001). In 10% of patients with ApHCM, perfusion defects were sufficiently apical that conventional short-axis views missed them. In 29%, stress myocardial blood flow fell below rest values. Stress myocardial blood flow was most impaired subendocardially, with greater hypertrophy or scar, and with apical aneurysms. Impaired apical myocardial blood flow was most strongly predicted by thicker apical segments (β-coefficient, -0.031 mL/g per min [CI, -0.06 to -0.01]; =0.013), higher ejection fraction (-0.025 mL/g per min [CI, -0.04 to -0.01]; <0.005), and ECG maximum R-wave height (-0.023 mL/g per min [CI, -0.04 to -0.01]; <0.005).
Apical perfusion defects are universally present in ApHCM at all stages. Its ubiquitous presence along with characteristic ECG suggests ischemia may play a disease-defining role in ApHCM.
心尖肥厚型心肌病（ApHCM）约占肥厚型心肌病病例的 10%，其特征为心尖部肥厚、心尖腔闭塞以及心电图 R 波增高伴缺血样深 T 波倒置。即使心尖部肥厚＜15mm（相对 ApHCM）也可能出现这些表现。肥厚型心肌病中微血管功能障碍已有充分描述。我们假设心尖部灌注缺陷在 ApHCM 中较为常见。
采用心血管磁共振短轴和长轴定量腺苷扩张剂应激灌注成像的 2 中心研究。将 100 例 ApHCM 患者（68 例为显性肥厚[≥15mm]和 32 例为相对 ApHCM）与 50 例不对称性室间隔肥厚型肥厚型心肌病患者和 40 例健康志愿者对照进行比较。通过视觉和定量方法评估灌注情况，作为心肌血流和心肌灌注储备。
所有显性 ApHCM 患者（100%）、所有相对 ApHCM 患者（100%）、36%的不对称性室间隔肥厚型肥厚型心肌病患者以及 0%的健康志愿者均存在心尖部灌注缺陷（＜0.001）。在 10%的 ApHCM 患者中，灌注缺陷在心尖部过于明显，常规短轴视图无法发现。29%的患者应激心肌血流低于静息值。心内膜下心肌血流受损最严重，与肥厚或瘢痕程度较大以及心尖部瘤相关。心尖段较厚（β系数，-0.031mL/g/min[CI，-0.06 至-0.01]；=0.013）、射血分数较高（-0.025mL/g/min[CI，-0.04 至-0.01]；＜0.005）和心电图最大 R 波高度较高（-0.023mL/g/min[CI，-0.04 至-0.01]；＜0.005）与心尖部心肌血流受损相关性最强。
在 ApHCM 的所有阶段，心尖部灌注缺陷普遍存在。其普遍存在和特征性心电图提示缺血可能在 ApHCM 中起定义疾病的作用。
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