Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA.
Department of Biomedical Statistics and Informatics, Mayo Clinic, Mayo Clinic, Rochester, MN 55905, USA.
Eur Heart J. 2021 Feb 14;42(7):776-785. doi: 10.1093/eurheartj/ehaa941.
Cardiac power is a measure of cardiac performance that incorporates both pressure and flow components. Prior studies have shown that cardiac power predicts outcomes in patients with reduced left ventricular (LV) ejection fraction (EF). We sought to evaluate the prognostic significance of peak exercise cardiac power and power reserve in patients with normal EF.
We performed a retrospective analysis in 24 885 patients (age 59 ± 13 years, 45% females) with EF ≥50% and no significant valve disease or right ventricular dysfunction, undergoing exercise stress echocardiography between 2004 and 2018. Cardiac power and power reserve (developed power with stress) were normalized to LV mass and expressed in W/100 g of LV myocardium. Endpoints at follow-up were all-cause mortality and diagnosis of heart failure (HF). Patients in the higher quartiles of power/mass (rest, peak stress, and power reserve) were younger and had higher peak blood pressure and heart rate, lower LV mass, and lower prevalence of comorbidities. During follow-up [median 3.9 (0.6-8.3) years], 929 patients died. After adjusting for age, sex, metabolic equivalents (METs) achieved, ischaemia/infarction on stress test results, medication, and comorbidities, peak stress power/mass was independently associated with mortality [adjusted hazard ratio (HR), highest vs. lowest quartile, 0.5, 95% confidence interval (CI) 0.4-0.6, P < 0.001] and HF at follow-up [adjusted HR, highest vs. lowest quartile, 0.4, 95% CI (0.3, 0.5), P < 0.001]. Power reserve showed similar results.
The assessment of cardiac power during exercise stress echocardiography in patients with normal EF provides valuable prognostic information, in addition to stress test findings on inducible myocardial ischaemia and exercise capacity.
心输出功率是一种综合压力和流量成分的心脏功能指标。先前的研究表明，心输出功率可预测左心室射血分数（LVEF）降低的患者的预后。我们旨在评估在射血分数正常的患者中，峰值运动心输出功率和功率储备的预后意义。
我们对 2004 年至 2018 年间接受运动超声心动图检查、射血分数≥50%且无明显瓣膜疾病或右心室功能障碍的 24885 例患者（年龄 59±13 岁，45%为女性）进行了回顾性分析。将心输出功率和功率储备（应激时产生的功率）标准化为左心室质量，并以每 100g 左心室心肌的瓦特数表示。随访终点为全因死亡率和心力衰竭（HF）的诊断。心输出功率/质量较高四分位数（静息时、峰值应激时和功率储备时）的患者年龄较小，峰值血压和心率较高，左心室质量较低，合并症的患病率较低。在随访期间[中位数 3.9（0.6-8.3）年]，有 929 例患者死亡。在调整年龄、性别、代谢当量（METs）、应激试验结果缺血/梗死、药物治疗和合并症后，峰值应激时心输出功率/质量与死亡率[调整后的危险比（HR），最高四分位与最低四分位，0.5，95%置信区间（CI）0.4-0.6，P<0.001]和随访时 HF[调整后的 HR，最高四分位与最低四分位，0.4，95%CI（0.3，0.5），P<0.001]独立相关。功率储备也得到了类似的结果。
在射血分数正常的患者中，运动超声心动图评估心输出功率除了评估应激试验诱导的心肌缺血和运动能力外，还提供了有价值的预后信息。
