基于时间射血分数评估心功能的设想

A conception of evaluating cardiac function based on timed ejection fraction

射血分数(ejection fraction,EF)是每搏输出量与心室舒张末容积的百分比,由于没有时间限制,不能反映心脏射血的敏捷性与时效性,为泵血功能的总体反映。在目前射血分数保留的心衰(heart failure with preserved EF,HFp EF)患者日益增多的条件下,EF临床意义有限。而泵血是心脏最基本的功能,在EF无法评估心功能的条件下,如何用其他相对客观且简单指标进行心功能评估于临床显得尤为重要。虽已有较多相关研究,但结果均不理想。而心电图QRS波时限与心肌收缩时间有较好的相关性,满足时间射血分数(timed EF,TEF)中时间因素的要求,符合用TEF代替传统的EF的设想,即以EF与心电图QRS波时限比值评估心功能。它既包含心脏原有的EF,又加入特定的时间限制,能较全面而客观地反映心脏实际泵血能力,特别是对HFp EF患者和心衰早期患者心功能的评估,是心脏泵血功能评估新指标的有益尝试和探讨。

Ejection fraction（EF） is defined as the percentage of stroke volume divided by the ventricular end-diastolic volume. Without time limited, it cannot reflect the dexterity and effectiveness of myocardial contraction, but only the general pumping function. Its clinical value is restricted under the condition of increasing number of patients with heart failure with preserved EF（HFp EF）. So how to use a relatively objective and simple factor to evaluate heart pumping function becomes more important in the clinical setting. Although some related studies have been done in the field, the results are unsatisfactory. In this article, we imagine adopting a new index to replace the conventional EF. As the time of electrocardiogram QRS complex has a good correlation with the time of myocardial contraction, we proposed a timed ejection fraction（TEF）, a ratio of assumption based on the traditional EF divided by the time of electrocardiogram QRS complex. It contains both the heart EF and a limited time, meeting the requirement of the time factor in the EF. It maybe assesses heart pumping function better, especially to the patients with HFp EF or early heart failure. Moreover, it is a beneficial try and discussion to evaluate cardiac pumping function with a new method.