EP：伴左室收缩功能减低的无器质性心脏病室性早搏患者的心电图及心电生理特征

室性早搏在无器质性心脏病患者中十分常见，已有报道表明频发的室性早搏与左室功能减退及左室扩大相关，而这些改变可在对室性早搏进行射频消融后完全逆转。室性早搏导致的左室功能障碍的发生机制主要包括钙离子稳态的异常、氧消耗增加及左心室收缩不同步。室性早搏相关的左室功能障碍也可发生在疤痕性室早的患者，这进一步减低了左心室功能。室性早搏导致的左室收缩功能异常的相关危险因素目前还不明确，部分研究表明室早的负荷、形态、起源部位决定是否发生左室收缩功能障碍，但这些报道得出的结论不一，据此Ban JE等进行了一项临床研究，旨在研究室性早搏导致左室功能障碍患者的心电图及心电生理特点。

该研究共入选127例患者，所有患者均因频发室早（室早负荷>10%）进行了射频消融术，所有患者均未发现器质性心脏病。28例患者存在左室收缩功能障碍，即LVEF<50%,占22%。与LVEF正常的患者相比，LVEF减低的患者室早负荷更大（31%比22%），存在非持续性室速的比例更大（53.6%比33.3%），室早后存在逆行P波的概率更大（64.3%比30.3%）。室性早搏负荷的界定点为26%，其敏感性为70%，特异性为78%。再组相比，室性早搏形态、QRS波电轴、QRS波宽度、联律间期、插入性室早及运动时室早的出现情况均无明显差异。两组的室性早搏起源部位、消融成功率及复发率均相似，无显著地统计学差异。多因素分析提示，室性早搏负荷与室早后逆行P波是室早导致左室收缩功能障碍的独立预测因子，二者的P值分别为0.006和0.034。

根据该项研究可得出如下结论：高室性早搏负荷（>26%）和逆行P波的存在是室早导致左室收缩功能障碍的独立危险因素.

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Electrocardiographic and electrophysiological characteristics of premature ventricular complexes associated with left ventricular dysfunction in patients without structural heart disease

ABSTRACT
Aims The mechanism responsible for premature ventricular complex (PVC)-mediated left ventricular (LV) dysfunction remains unclear. We sought to determine the electrocardiographic and electrophysiological characteristics of PVC-mediated LV dysfunction. Methods and results One hundred and twenty-seven patients who underwent radiofrequency catheter ablation (RFCA) for frequent PVCs (PVCs burden ≥10%/24 h) and had no significant structural heart disease were investigated. Left ventricular dysfunction (ejection fraction < 50%) was present in 28 of 127 patients (22.0%). The mean PVC burden (31 ± 11 vs. 22 ± 10%, P < 0.001), the presence of non-sustained ventricular tachycardia (53.6 vs. 33.3%, P = 0.05), and the presence of a retrograde P-wave following a PVC (64.3 vs. 30.3%, P = 0.001) were significantly greater in those with LV dysfunction than in those with normal LV function. The cut-off PVC burden related to LV dysfunction was 26%/day, with a sensitivity of 70% and a specificity of 78%. The PVC morphology, QRS axis, QRS width, coupling interval, the presence of interpolation, and PVC emergence pattern during exercise electrocardiogram were not significantly different between the two groups. The origin sites of PVCs, the acute success rate, and the recurrence rate during follow-up after RFCA were similar. In a multivariate analysis, the PVC burden (odds ratio 2.94, 95% confidence interval 0.90–3.19, P = 0.006) and the presence of retrograde P-waves (odds ratio 2.79, 95% confidence interval 1.08–7.19, P = 0.034) were independently associated with PVC-mediated LV dysfunction. Conclusion A higher PVC burden (>26%/day) and the presence of retrograde P-waves were independently associated with PVC-mediated LV dysfunction.