Ideal heart rate (HR), particularly for those with heart failure with preserved ejection fraction (HFpEF), remains unknown. We hypothesized that cardiac output would be maximum when the overlap between E-wave and A-wave at the trans-mitral flow is "zero" in the Doppler echocardiography. We retrospectively investigated the association among the overlap length between two waves, actual HR, and other echocardiographic parameters to construct a formula for estimating theoretically ideal HR among those with HFpEF. In total, 48 HFpEF patients were included (70-year-olds, 18 males). Given the results of multivariate linear regression analyses, the overlap length was estimated as follows: -1,050 + 8.4 × (HR [bpm]) + 0.6 × (deceleration time [millisecond]) + 1.7 × (A-width [millisecond]), which had a strong agreement with the actually measured overlap length (r = 0.86, P < 0.001). Theoretically ideal HR was calculated by substituting zero into the estimated overlap length as follows: 125 − 0.07 × (deceleration time [millisecond]) − 0.20 × (A-width [millisecond]). In the validation cohort including another 143 HFpEF patients, the estimated overlap using the formula again had a strong agreement with the actually measured overlap (r = 0.72, P < 0.001). In this study, we proposed a novel formula for calculating theoretically ideal HR, consisting of deceleration time and A-width, in the HFpEF cohort. Clinical implication to optimize the HR targeting the theoretically ideal HR should be investigated in prospective studies.

理想心率 (HR)，尤其是那些射血分数保留的心力衰竭 (HFpEF) 的患者，仍然未知。我们假设在多普勒超声心动图中，当跨二尖瓣血流中 E 波和 A 波之间的重叠为“零”时，心输出量将是最大的。我们回顾性研究了两个波之间的重叠长度、实际 HR 和其他超声心动图参数之间的关联，以构建一个公式来估计 HFpEF 患者理论上理想的 HR。总共包括 48 名 HFpEF 患者（70 岁，18 名男性）。鉴于多元线性回归分析的结果，重叠长度估计如下：-1,050 + 8.4 × (HR [bpm]) + 0.6 × (减速时间 [毫秒]) + 1.7 × (A 宽度 [毫秒])，r = 0.86，P < 0.001）。理论上理想的 HR 是通过将零代入估计的重叠长度来计算的，如下所示：125 - 0.07 ×（减速时间 [毫秒]） - 0.20 ×（A 宽度 [毫秒]）。在包括另外 143 名 HFpEF 患者的验证队列中，使用该公式估计的重叠再次与实际测量的重叠非常一致（r = 0.72，P < 0.001）。在这项研究中，我们提出了一个新的公式来计算理论上理想的 HR，包括减速时间和 A 宽度，在 HFpEF 队列中。应在前瞻性研究中研究针对理论上理想的 HR 优化 HR 的临床意义。