长期右心室心尖部起搏对三度房室阻滞患者心功能的影响

The impact of chronic right ventricniar apical pacing on cardiac function in patients with third degree atrioventricniar block

目的了解长期持续右心室心尖部（RVA）起搏对基础心功能正常患者心脏结构和功能的影响及其危险因素。方法选取基础心功能正常、因三度房室阻滞（AVB）而植入VVI或DDD起搏器的患者为研究对象，观察其是否出现心力衰竭相关症状或因心力衰竭入院，同时行超声心动图随访，并对相关临床因素进行分析。心力衰竭的定义为随访中出现因心力衰竭入院或死亡、或超声心动图示左心室射血分数（LVEF）≤0．40。左心室（LV）结构、功能受损是指超声心动图观察到的LV局部或总体收缩活动减弱、LVEF〈0．50或左心室舒张末期内径（LVEDD）〉56mm之任意一项。结果共141例患者平均随访8．3年后，8例（5．7％）出现心力衰竭，20例（14．2％）出现左心室结构、功能受损；其发生率均随起搏时间增长而增加。随访中患者平均LVEF下降、平均LVEDD增加，但其起搏前后的差异并无统计学意义。患者性别、植入起搏器时年龄、起搏模式以及是否合并高血压、糖尿病、冠心病、心房扑动和心房颤动等因素均与心力衰竭发生或左心室结构、功能受损无关。结论长期RVA起搏者存在心脏结构和功能受损的可能，起搏时问越长发生几率越高，但其危险因素尚不明确。

Objective This study was aimed to evaluate the incidence and risk factors of new-onset heart failure （HF） and left ventricular （LV） dysfunction in patients with normal baseline heart function who underwent permanent right ventricular apical（RVA） pacing. Methods In this study we retrospectively investigated LV function changes after long-term RVA pacing for third degree atrioventricular block （ AV block） in patients with preserved heart function and without severe structural heart diseases. New-onset HF was defined as hospitaliztion for HF,or death from HF,or LV ejection fraction （LVEF） ≤0.40 evaluated by echocardiography （echo） in this study. And LV dysfunction was defined as either general or regional wall motion abnormality of LV,or LVEF impairment （ 〈 0. 50）, or LV enlargement （ LVEDD 〉 56 mm）, which was also evaluated by echo. Finally, some relating clinical features of the patients were investigated for risk factor analysis. Results A total number of 141 patients were finally included in this study. After （8. 3 ± 6. 4 ） years of follow-up, 8 of them （5.7%） developed new-onset HF,and 20 of them （14. 2% ） developed LV dysfunction. Higher incidences of both new-onset HF and LV dysfunction were observed in groups of longer pacing history. After （ 5.6 ± 4. 3 ） years of follow-up, the average LVEF and LVEDD levels for 70 patients were not statistically different from those before pacing. Single factor analysis of the patients＇ gender, age at implantation, pacing mode （VVI or DDD）, presence of hypertension,diabetes, coronary heart disease, atrial fibrillation （AF） or atrial flutter showed that none of them were related with new-onset HF or LV dysfunction after pacing. Conclusion Among patients with normal baseline LV function who underwent permanent RVA pacing, a certain number of them did develop newonset HF or LV dysfunction （ with or without HF symptoms）. The incidence of LV function decline had a tend- ency to increase with the growth of pacing years for those patients. However, other risk factors remained unknown.