| Objective: Studies have shown that right ventricular apical pacing has many disadvantages. With the deepening understanding of the physiological pacing, selective site in right ventricular pacing has become a hot spot in recent years. In this study we aimed to investigate the implantation of right ventricular septum pacing leads through the comparative analysis of CT and X-ray image characteristics, to provide a reference for pacemaker lead location.Subject: 33 patients scheduled for double chamber permanent pacemaker implantation, which met the class ⅠorⅡ a pacemaker installed indications, were enrolled for this study between January 2013 and January 2015 at the Second Hospital of Hebei Medical University. There were 18 female and 15 male, they were 42 to 82 years old. Including 25 of them have sick sinus syndrome and 8 of them have second or higher degree atrioventricular block.Method: Following device implantation, fluoroscopic radiographs were recorded in three views: posterior-anterior(PA), 30? RAO, 45? LAO. Lead position in the PA view was implanted in the high septum of right ventricular(the low septum of RVOT) or the middle septum of right ventricular(Fig.1). In the 30°RAO the right ventricular septum was divided into nine parts. We located the electrode in the middle region(Fig.2).In the 40°LAO view, leads were classified as septum if they faced to the right, and free wall if directed to the left(Fig. 3). Through the above three views, we thought the electrode was located in the right ventricular septum region. 5 to 7 days after pacemaker implantation patients had CT examination in order to make clear the exact location of right ventricular pacing lead.Statistical analysis: The measurement data were represented as mean ±SD. The count data were represented as a percentage. All the statistical examinations of measurement data were performed using either independent samples t-test or paired-samples t-test by SPSS 16.0 software. All the statistical examinations of count data were performed using chi-square test,P<0.05 was considered statistically significant.Results:1 CT is useful to rebuild the ventricular septum and show the positionof the pacemaker electrode.2 The lead was implanted on the high septum of right ventricular in 9 patients(27.3%), on the middle septum of right ventricular in 13 patients(39.4%), on the free wall of right ventricular in 11 patients(33.3%).3 According to the right ventricle enhanced CT of right ventricular pacing leads location we divided the patients into two groups: septum and the free wall group. The QRS durations of two groups were significantly lengthened compared with baseline electrocardiography(P < 0.05). And there was significant difference in QRS duration between septum and the free wall group(P<0.05).4 The QRS duration of the middle septum, the high septum, the middle free wall and the high free wall have no significant difference between each other(P>0.05).5 There were 22 cases(100%) in RVS group leadⅠis positive, free wall group of 10 cases(90.9%) of lead Ⅰis positive, there was no statistically significant difference between two groups(P = 0.333).6 There were 11 cases(50%) in RVS group have notching in inferior leads, while 1case(9.1%) in free wall group, and there was significant difference between two groups(P<0.05).Conclusion:1 CT can indicate the precise position of the pacemaker electrode successfully.2 On the basis of conventional X-ray positioning, most right ventricular electrode can be implanted into the right ventricle septum, but there are still a part of the implant the harmful of right ventricular free wall, we may need to be combined with other auxiliary measures in order to locate the electrode in the septum.3 There is no unified electrocardiogram standard differential interval pacemaker and free wall pacemaker. |
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