Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.
Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota.
J Am Soc Echocardiogr. 2022 Nov;35(11):1139-1145.e3. doi: 10.1016/j.echo.2022.07.008. Epub 2022 Jul 19.
Cardiac power reflects cardiac performance in terms of energy transferred by the left ventricle to the aorta per unit time. Peak stress cardiac power has been shown to predict outcomes in patients with reduced left ventricular ejection fraction (LVEF) and, more recently, in patients with normal LVEF referred for exercise stress echocardiography. The aim of this study was to evaluate the prognostic significance of cardiac power in patients with normal LVEF referred for dobutamine stress echocardiography.
Data were studied from 15,576 patients with LVEF ≥ 50% and no significant valvular or right ventricular dysfunction who underwent dobutamine stress echocardiography. Cardiac power at rest and peak stress and power reserve (peak stress minus rest power) were calculated and normalized to left ventricular mass. Outcome end points were all-cause mortality and new-onset heart failure (HF).
The mean age was 66 ± 13 years, and 49% patients were women. Resting and peak stress power/mass were 0.7 ± 0.2 and 1.6 ± 0.6 W/100 g left ventricular myocardium, respectively. During follow-up (median, 3.3 years; interquartile range, 0.7-7.3 years), 2,278 patients died and 2,137 developed HF. After adjusting for age, sex, comorbidities, and stress test results, lower peak stress power/mass was independently associated with mortality (adjusted hazard ratio, highest vs lowest quartile, 0.84; 95% CI, 0.74-0.95; P = .004) and HF at follow-up (adjusted hazard ratio, 0.67; 95% CI, 0.59-0.76; P < .0001). Power reserve showed similar associations with outcomes.
Assessment of cardiac power during dobutamine stress echocardiography in patients with normal LVEF provides valuable prognostic information regarding risk for mortality and future HF, in addition to stress test results. It is an important research tool to study cardiac performance, and the development of risk scores incorporating this novel index could be considered after further validation in prospective studies.
心功率反映了左心室在单位时间内向主动脉传递的能量所代表的心脏功能。峰值压力心功率已被证明可预测左心室射血分数（LVEF）降低的患者的预后，最近也可预测接受运动负荷超声心动图检查的 LVEF 正常的患者的预后。本研究旨在评估 LVEF 正常的患者接受多巴酚丁胺负荷超声心动图检查时心功率的预后意义。
研究分析了 15576 例 LVEF≥50%且无明显瓣膜或右心室功能障碍的患者的数据，这些患者均接受了多巴酚丁胺负荷超声心动图检查。计算并将静息和峰值负荷时的心脏功率以及功率储备（峰值负荷减去静息时的功率）标准化为左心室质量。研究终点为全因死亡率和新发心力衰竭（HF）。
患者的平均年龄为 66±13 岁，49%为女性。静息和峰值负荷时的心脏功率/质量分别为 0.7±0.2 和 1.6±0.6 W/100 g 左心室心肌。在随访期间（中位数 3.3 年；四分位距 0.7-7.3 年），2278 例患者死亡，2137 例发生 HF。在调整年龄、性别、合并症和负荷试验结果后，较低的峰值负荷功率/质量与死亡率（最高四分位组与最低四分位组校正后 HR，0.84；95%CI，0.74-0.95；P=0.004）和随访时 HF（校正后 HR，0.67；95%CI，0.59-0.76；P<0.0001）独立相关。功率储备与结局也有类似的相关性。
在 LVEF 正常的患者中，多巴酚丁胺负荷超声心动图检查时评估心功率可提供有价值的预后信息，不仅包括与应激试验结果相关的死亡率和未来 HF 的风险，还包括其他信息。它是一种重要的研究工具，可用于研究心脏功能，在进一步的前瞻性研究验证后，可以考虑将该新型指标纳入风险评分。
