Raw data of paper entitled: "What about chronotropic incompetence in heart failure with mildly reduced ejection fraction? Clinical and prognostic implications from the MECKI score data-set"

Aims: Chronotropic incompetence (CI) is a strong predictor of outcome in heart failure with reduced ejection fraction, however no data on its clinical and prognostic impacts in heart failure with mildly reduced ejection fraction (HFmrEF) are available. Therefore, the study aims to investigate, in a large multicentre HFmrEF cohort, the prevalence of CI as well as its relationship with exercise capacity and its prognostic role over the cardiopulmonary exercise testing (CPET) parameters. Methods and results: Within the Metabolic Exercise combined with Cardiac and Kidney Indexes (MECKI) database, we analysed data of 864 HFmrEF out of 1164 stable outpatients who performed a maximal CPET at the cycle ergometer and who had no significant rhythm disorders or comorbidities. The primary study endpoint was cardiovascular (CV) death. All-cause death was also explored. Chronotropic incompetence prevalence differed depending on the method (peak heart rate, pHR% vs. pHR reserve, pHRR%) and the cut-off adopted (pHR% from ≤75% to ≤60% and pHRR% ≤ 65% to ≤50%), ranging from 11% to 62%. A total of 84 (9.7%) CV deaths were collected, with 39 (4.5%) occurring within 5 years. At multivariate analysis, both pHR% [hazard ratio 0.97 (0.95-0.99), P < 0.05] and pHRR% [hazard ratio 0.977 (0.961-0.993), P < 0.01] were associated with the primary endpoint. A pHR% ≤ 75% and a pHRR% ≤ 50% represented the most accurate cut-off values in predicting the outcome. Conclusion: The study suggests an association between blunted exercise-HR response, functional capacity, and CV death risk among patients with HFmrEF. Whether the CI presence might be adopted in daily HFmrEF management needs to be addressed in larger prospective studies.研究目的：变时性功能不全（Chronotropic incompetence, CI）是射血分数降低型心力衰竭患者预后的强预测因子，但目前尚无关于其在射血分数轻度降低型心力衰竭（heart failure with mildly reduced ejection fraction, HFmrEF）中临床与预后影响的相关数据。因此本研究旨在依托大型多中心HFmrEF队列，探究CI的患病率，及其与运动能力的关联，并分析其基于心肺运动试验（cardiopulmonary exercise testing, CPET）参数的预后价值。 研究方法与结果：本研究依托代谢运动联合心脏与肾脏指标（Metabolic Exercise combined with Cardiac and Kidney Indexes, MECKI）数据库，对1164名完成自行车测力计极量心肺运动试验、无明显节律异常或合并症的稳定门诊患者中的864名HFmrEF患者数据进行分析。本研究的主要终点为心血管（Cardiovascular, CV）死亡，同时也探索了全因死亡结局。CI的患病率因计算方式（峰值心率百分比pHR%与峰值心率储备百分比pHRR%）及采用的截断值（pHR%从≤75%调整至≤60%，pHRR%从≤65%调整至≤50%）存在差异，患病率范围为11%至62%。最终共纳入84例（9.7%）心血管死亡病例，其中39例（4.5%）发生于随访5年以内。多因素分析显示，pHR%[风险比0.97（95%置信区间0.95~0.99），P<0.05]与pHRR%[风险比0.977（95%置信区间0.961~0.993），P<0.01]均与主要研究终点显著相关。其中pHR%≤75%与pHRR%≤50%为预测预后的最优截断值。 研究结论：本研究结果提示，HFmrEF患者的运动心率反应迟钝、功能储备与心血管死亡风险之间存在关联。CI是否可应用于HFmrEF的日常临床管理，仍需开展更大规模的前瞻性研究加以验证。