Background: Genetic evaluation is recommended in patients with unexplained dilated cardiomyopathy (DCM), but its diagnostic yield and prognostic relevance in unexplained isolated left ventricular dysfunction (LVdys) is unknown.

Methods and Results: A total of 127 LVdys and 262 DCM patients underwent genetic screening. Long-term outcome consisted of a combined end point of life-threatening arrhythmia, heart transplantation, and death. At baseline, LVdys patients were younger and had less frequently New York Heart Association class ≥3 when compared with DCM (55±13 versus 58±12; P=0.019 and 21% versus 36%; P=0.003, respectively). The prevalence of familial disease and pathogenic mutations was similar in LVdys and DCM (45% versus 40%; P=0.37 and 19% versus 17%; P=0.61, respectively). After a follow-up of 56 (31–82) months, outcome did not differ in LVdys compared with DCM patients (hazard ratio, 0.83; 95% confidence interval, 0.47–1.45; P=0.51). Overall, outcome was less favorable in patients with a genetic mutation or familial disease when compared with those without (hazard ratio, 2.7; 95% confidence interval, 1.07–7.7; P=0.048 and hazard ratio, 2.2; 95% confidence interval, 1.2–4.2; P=0.013, respectively). Thus, the diagnostic yield of genetic testing in LVdys and DCM is similarly high. The presence of a gene mutation or familial predisposition results in an equally worse prognosis.

Conclusions: Genetic evaluation is advised in LVdys patients and should not merely be restricted to DCM.

背景：对于不明原因的扩张型心肌病（DCM）患者，建议进行遗传学评估，但对于不明原因的孤立性左心功能不全（LVdys）的诊断率和预后相关性尚不清楚。

方法和结果：共有127例LVdys和262例DCM患者接受了基因筛查。长期预后包括危及生命的心律失常，心脏移植和死亡的综合终点。与DCM相比，LVdys患者在基线时更年轻，并且其纽约心脏病协会的≥3级患者的频率更低（分别为55±13对58±12；P = 0.019； 21％对36％；P = 0.003）。LVdys和DCM中家族性疾病和致病性突变的患病率相似（分别为45％对40％；P = 0.37和19％对17％；P = 0.61）。随访56（31–82）个月后，LVdys与DCM患者的结局无差异（危险比，0.83； 95％置信区间，0.47–1.45；P = 0.51）。总体而言，与没有遗传突变或家族性疾病的患者相比，遗传突变或家族性疾病患者的预后较差（危险比：2.7； 95％置信区间：1.07-7.7；P = 0.048；危险比：2.2； 95％置信区间：1.2 –4.2；P = 0.013）。因此，LVdys和DCM中基因检测的诊断产率同样很高。基因突变或家族易感性的存在同样会导致更差的预后。

结论： LVdys患者建议进行遗传评估，而不仅限于DCM。