National Heart Research Institute Singapore, National Heart Center Singapore, 5 Hospital Drive, Singapore, Singapore.
Cardiovascular Sciences ACP, Duke NUS Medical School, Singapore, Singapore.
J Cardiovasc Magn Reson. 2020 Feb 3;22(1):10. doi: 10.1186/s12968-020-0598-4.
The imaging features of dilated cardiomyopathy (DCM) overlap with physiological exercise-induced cardiac remodeling in active and otherwise healthy individuals. Distinguishing the two conditions is challenging. This study examined the diagnostic and prognostic roles of exercise stress imaging in asymptomatic patients with suspected DCM.
Exercise stress cardiovascular magnetic resonance (CMR) was performed in 60 asymptomatic patients with suspected DCM (dilated left ventricle and/or impaired systolic function on CMR), who also underwent DNA sequencing for DCM-causing genetic variants. Confirmed DCM was defined as genotype- and phenotype-positive (G+P+). Another 100 healthy subjects were recruited to establish normal exercise capacities (peak exercise cardiac index; Peak). The primary outcome was a composite of all-cause mortality, cardiac decompensation and ventricular arrhythmic events.
No patients with confirmed G+P+ DCM had Peak exceeding the 35th percentile specific for age and sex. Applying this threshold in G-P+ patients, those with Peak below 35th percentile had characteristics similar to confirmed DCM while patients with higher Peak were younger, more active and higher longitudinal strain. Adverse cardiovascular events occurred only in patients with low exercise capacity (P = 0.004).
In individuals with suspected DCM, exercise stress CMR demonstrates diagnostic and prognostic potential in distinguishing between pathological DCM and physiological exercise-induced cardiac remodeling.
扩张型心肌病（DCM）的影像学特征与活跃且健康个体的生理性运动引起的心脏重塑相重叠。区分这两种情况具有挑战性。本研究探讨了运动应激成像在疑似 DCM 的无症状患者中的诊断和预后作用。
对 60 名疑似 DCM（CMR 显示左心室扩张和/或收缩功能受损）的无症状患者进行运动应激心血管磁共振（CMR）检查，这些患者还接受了 DCM 致病基因突变的测序。经基因和表型阳性（G+P+）证实的 DCM 被定义为确诊 DCM。另外招募了 100 名健康受试者来建立正常的运动能力（峰值运动心指数；Peak）。主要结局是全因死亡率、心脏失代偿和室性心律失常事件的综合指标。
没有确诊的 G+P+DCM 患者的 Peak 超过了特定年龄和性别的第 35 百分位。在 G-P+患者中应用这一阈值，Peak 低于第 35 百分位的患者具有与确诊 DCM 相似的特征，而 Peak 较高的患者更年轻、更活跃且纵向应变更高。不良心血管事件仅发生在运动能力较低的患者中（P=0.004）。
在疑似 DCM 的个体中，运动应激 CMR 在区分病理性 DCM 和生理性运动引起的心脏重塑方面具有诊断和预后潜力。
