右室永久起搏可行的后备电极放置部位——右室流出道

为探讨冠心病心肌纤维化、合并糖尿病或恶性肿瘤放射治疗后出现房室阻滞的患者右室永久起搏可行的后备电极放置部位，对３例电极脱位至右室流出道、９例因上述疾病主动将电极置入右室流出道的患者进行了起搏阈值测定及随访。结果：１２例患者右室流出道起搏阈值（电压：０．８６±０．１０Ｖ，脉宽：０．３±０．０４ｍｓ）较右室心尖部起搏阈值（电压：５．０±６．０６Ｖ，脉宽：１．５２±０．７７ｍｓ）显著降低，Ｐ＜０．０１。随访６８．５±３４．６５个月无电极脱位，起搏功能良好。结果提示右室流出道是永久起搏可行的后备电极放置部位。

Right Ventricular Outflow Tract as An Alternative Permanent Pacing Site

In patients with myocardial fibrosis type of coronary heart disease,especially complicating diabetes mellitus or combined radiation therapy for treatment of malign tumor,during cardiac pacing,pacing threshold in some cases is increasing significantly.For investigating an alternative permanent pacing site in right ventricular outflow tract (RVOT)to the right ventricular apex,in 12 such patients,permanent pacing electrode (straight tined endocardial lead and programmable pacemaker)was inserted onto the RVOT(including disloged pacemaker electrode reimplanted onto the RVOT in 3 cases).The result showed that the pacing threshold on RVOT in pulse amplitude was 0.86±0.1 V,in pulse width was 0.3±0.04 ms; but in right ventricular apex,the pulse amplitude was 5.0±6.06 V,in pulse width was 1.52±0.77 ms(both pulse amplitude and pulse width, P <0.01).In long term follow up(68.5±34.65 months),it showed that there was no electrode dislogement,a good pacing condition had been maintained.It is considered that RVOT as an alternative permanent pacing site is highly satisfactory.