室性期前收缩对无器质性心脏病患者心功能的影响

室性期前收缩是最常见的室性心律失常,不伴有器质性心脏病的室性期前收缩,通常被认为是良性的,但近10年的研究发现,频发室性期前收缩在某些条件下可导致左室重构,甚至诱发心力衰竭症状.这些条件包括患者年龄、病程长短、室性期前收缩负荷及室性期前收缩的起源部位和室性期前收缩QRS波的宽度.诱发心力衰竭的机制可能与室性期前收缩时左右心室失同步、心肌细胞能量储备耗竭、心内膜下至心外膜下血流比失调导致心肌缺血、钙平衡失调、氧自由基损伤,以及β受体密度下调、反应性下降等多种病理生理因素有关.近来有学者提出“室性期前收缩诱发的心肌病”的概念,和心动过速性心肌病一样,也可能成为一种独立的未分类心肌病.

Influence of Premature Ventricular Contractions on Cardiac Function in Patients Without Structual Heart Disease

Premature ventricular contractions （PVCs） are the most common ventricular arrhythmias in clinical practice and usually considered benign in patients with normal heart, even when frequent. However, clinical researches have demonstrated a possible link between frequent PVCs and left ventricular （LV） remodelling or LV dysfunction. The duration, burden and originating site of PVCs, the age of patients and PVCs QRS duration have been shown to be associated with the process of LV remodelling. The underlying mechanisms include desynchronization motion of ventricles, depletion of myocardial energy stores, abnormalities in subendocardial to subepicardial flow ratios and impaired coronary flow leading to myocardial ischaemia, abnormalities in calcium handling, and reduced responsiveness or down-regulation of beta-adrenergic receptor, and free radical oxidative stress injury. As same as tachycardia-induced cardiomyopathy, PVCs induced cardiomyopathy have been presented as a new concept of unclassified cardiomyopathy.