| Background:In October1958, Doctor Ake Senning of Karolinska hospital in Stockholm, Sweden, succeeded in implementing the first case of fully-buried artificial cardiac pacemaker. Since the advent of artificial cardiac pacemaker, the development of pacemaker has had a history of more than50years. The progress of scientific technology has made the volume of pacemaker smaller and smaller, its using tile longer and longer, and its functions more and more improved. Thanks to the invention of pacemaker, some diseases that used to be thought of being clinically irremediable now has been remedied, and the wide application of pacemaker has also saved lives of many patients. Among adults, especially among senior citizens, the use ratio of pacemaker is relatively higher. For senior citizens, senile degenerated cardiac valve disorders cause cardiac conducting system barrier, heart disease associated with other natures, or arrhythmia, so they need permanent pacemaker therapy. The application of children’s permanent pacemaker is as well increasing, such as the application in the irrecoverable high-grade atrioventivular conduction block after the operation of fulminant myocarditis and congenital heart disease, congenital three-dimensional atrioventricular conduction block, sick sinus syndrome, partial dilated cardiomyopathy, hypertrophic cardiomyopathy and long Q-T syndrome and so on. Yet, compared with adults, children have their own peculiarity; children are younger, and their physiogenesis, blood vessel conditions and underlying disease constitution are different. Therefore, there are different pacemakers with different functions, implanting methods and fixation positions of electrode wires to choose. So it is necessary to be prudent when choosing functions, electrode implant methods and wire fixation positions of children’s pacemakers. Below is a brief introduction of common indications when implanting children’s pacemakers, including the following aspects.1. Accompanied with symptomatic bradycardia, such as height or three-degree atrioventricular block.2. Sinus node dysfunction in bradycardia incompatible with age, such as sick sinus syndrome.3. Height or three-degree atrioventricular block after the operation of congenital heart disease.4. Cardiomyopathy, such as dilated cardiomyopathy and hypertrophic cardiomyopathy that require permanent pacemaker therapy after assessment. Yet, because of the restriction of child patients’own conditions, take problem solutions and operation convenience and safety as the main principle when choosing the functions of pacemakers. The implanting methods of pacemakers fall into endocardium and epicardium, which depends on the age and physical conditions of child patients and is chosen by clinicians according to the specific circumstances of child patients. Main factors for consideration are age, blood vessel diameter of subclavian veins, thickness of chest wall subcutaneous tissues and underlying heart diseases and so on. Common implantation of endocardium pacemakers are usually applied in thick chest wall subcutaneous tissues, elder child patients and non-mechanical heart valve replacement. The common method, right ventricular apex pacing, for its intensive trabecular muscles, small blood flow shock, low dislocation rate, reliable pace-making, steady threshold value and simple operating techniques, is clinically widely used. The concrete operations in the child clinical application is insert the electrode wire from the jugular vein or subclavian vein under the condition of narcosis, usually of general anesthesia. Localize the position of electrode wire through X-ray, insert the electrode wire into the scheduled pace-making position of cardiac chambers, and then detect the functions of pacemaker wire after fixation. Bury the pacemaker connected with electrode wire inside the chest bladder bag, suture the skin layer by layer followed by pressure dressing, and thus is the completed operation. Epicardium pacemaker implantation is different from endocardium pacemaker implantation in that the former is usually for child patients who have thin chest wall subcutaneous tissues, younger age and poor blood vessel conditions and who have just had surgical open-heart surgery. The specific operating method is choosing below-xiphoid, subcostal and side open-heart methods under the condition of general anesthesia to expose the myocardium surface. Under the condition of orthophoria, fix the pacemaker electrode on the surface of myocardium after positioning. After detecting satisfying pace-making wire operation, bury the pacemaker connected with electrode wire into the chest or abdomen bladder bag, suture the wound layer by layer, and thus the operation is completed. For children, commoner pace-making way of permanent pacemakers is ventricle single-lumen pace-making method. Whether for endocardium or epicardium, the technology of ventricle single-lumen pace-making has been very mature and convenient to operate. However, with the long-term right ventricular apex pacing, many clinical researchers have found this kind of pace-making method influences the systolic synchronism of left and right ventricles; long-term right ventricular apex pacing can lead to left ventricular systolic dysfunction, cardiac failure and increased atrial fibrillation incidence [1]. The choice of the position closer to physiologic pacing is still in consistently arduous exploration. At present, for adults, researches [2]show the success rate is high, safe and effective when the pacing position is in the right ventricular outflow-tract septum whose pace-making is superior to that of cardiac apex pace-making in the aspects of cardiac function improvements, left and right ventricular synchronization and haemodynamics. Yet, due to the different constitution of children’s own characteristics and diseases, it awaits continuous research whether this pacing position possesses the above-mentioned advantages when applied in children. Because child patients are young, once the permanent pacemaker therapy is applied to them, their pacemaker change times are more than those of adults, and thus how to decrease the left ventricular systolic dysfunction, cardiac failure and atrial fibrillation incidence caused by long-term right ventricular apex pacing is more meaningful. Therefore, this subject research is put forward on the basis of adult pacemaker researches to observe whether right ventricular outflow-tract pacing can be applied to children and whether it is superior to right ventricular apex pacing.ObjectiveThis subject aim to study the way of implantation children’s permanent pacemaker.the changes of cardiac functions, pacing parameters and QRS duration of child patients’right ventricular outflow-tract pacing and right ventricular apex pacing by the intravenous route before and after implanting electrodes in children’s right ventricular single-lumen pacemaker therapy, as well as evaluating the feasibility of right ventricular outflow-tract pacing and whether it is superior to right ventricular apex pacing.MethodA retrospective analysis from March2006to November2013in the Guangdong Provincial People’s Hospital pediatric cardiac surgery and pediatric line of permanent pacemaker therapy in children92cases, of which transendocardial pacing therapy in children51cases were male25cases,26females, mean age (125.37±46.68) months,16cases of congenital heart disease, congenital heart disease,35cases no, VVI (R)38cases, ICD3cases, CRT (D)3cases DDD (R)7cases. Epicardial pacing therapy in children with41cases, including29males and12females, mean age (47.79±41.55) months,27cases of congenital heart disease, congenital heart disease,14cases no, VVI (R)30cases, CRT1cases, DDD (R)1cases, the implant body weight in children comparing two ways, age, length of stay, pacing, pacing lead replacements, pacemakers and replacement frequency of postoperative complications incidence of permanent pacemaker implantation analysis method of choice basis.Conforming with the indication of2012ACC/AHA pacemaker implantation guide, there are in the department of pediatrics in Guangdong Provincial People’s Hospital38cases of endocardium ventricular single-lumen pacemaker implantation. If divided according to the position of pacing electrode implantation, there are22cases of right ventricular outflow-tract group whose average (101.41±39.77) months old (x±s), among which11cases are males and11cases are females; and there are16cases of right ventricular apex group whose average age is (123.87±39.03) months (x±s), among which7cases are males and9cases are females. Among all the selected child patients, there are18cases of congenital three-degree atrioventricular block,5cases of myocarditis rear three-degree atrioventricular block,4cases of sick sinus syndrome,9cases of permanent pacemaker implantation after congenital heart disease surgery,1case of dilated cardiomyopathy and1case of long Q-T syndrome. Evaluate the safety and feasibility of right ventricular outflow-tract pacing by comparing pacing threshold values, R scope, electrode impedance and operative complications through program control and detection child patients’pacemakers before and after operation (5-7days). Compare the influence on the left and right ventricular systolic synchronism through QRS duration examined by pre-operation and post-operation ECG. Compare the influence of different pacing positions on cardiac functions through pre-operation and post-operation left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVEDD), left ventricular ejection fraction (LVEF) and left ventricular fraction shortening (LVFS) examined and recorded by thoracic cardiac color ultrasound cardiogram.Statistical treatmentThe statistical treatment applies SPSS19.0statistical package and Microsoft Excel software to statistical analysis. Factors affected by the pacemaker mode selection use multivariate logistic regression analysis.The measurement data adopts geometric mean±standard deviation (x±s), gender and disease constitution adopts chi-square test, complication, pacemaker replacement times and pacing lead replacement times adopts Fisher exact probability. When all the measurement data meet with normal distribution and homogeneity of variance after inspection, intra-group comparison adopts pairing t test, and comparison among groups adopts independent-sample t test, and there is statistical significance of difference when a<0.05.Results92cases were performed in children with permanent pacemaker implantation, endocardial and epicardial pacing pacing group in the age group [(125.37±46.68) months VS (47.79±41.55) months, t=8.32, P<0.001] and weight [(31.82±14.32) kg VS (12.41±6.98) kg, t=8.51, P<0.001], hospitalization [days (19.12±7.45) days VS (28.20±21.74) days, t=2.56, P=0.014<0.05], with or without congenital heart disease by chi-square test (χ2=10.86, P=0.002<0.05), the difference was statistically significant, endocardial pacing group of children over the age and weight of epicardial pacing group, short hospital stay compared with epicardial group, associated with congenital heart disease less than the heart epicardial groups. Factors found to affect the way that children implanted pacemaker weight by logistic regression analysis. Pacing lead replacement times by Fisher exact test, P=0.02, description endocardial pacing lead less than the epicardial pacing. Endocardial and epicardial pacemaker replacements Fisher exact test, P=0.15, the difference was not statistically significant. Endocardial and epicardial pacemaker replacement was no significant difference. Endocardial and epicardial pacemaker replacements Fisher exact test, P=0.15, the difference was not statistically significant.(see Table1、Table2)Complications endocardial pacing group of6cases,2deaths, one case of poor wound healing, one case of pericardial perforation, two case of cardiac perforation pocket infection and electrode replacement. Complications epicardial pacing group a total of11cases,3deaths, one case of wound healing,7cases of electrode replacement. Two sets of data by Fisher exact test, P=0.638, the difference was not statistically significant. Pacing complications illustrate two very different ways.(see Table1)All the38cases of child patients smoothly went through the fist VVI pacemaker implantation. There is no statistical significance of the difference (Table3) of right ventricular outflow-tract pacing group and cardiac apex pacing group in age independent-sample t test (8.45±3.31years old for right ventricular outflow-tract pacing group,10.32±3.2years old for right ventricular apex pacing group, P=0.092>0.05), male-female ratio through chi-square test (χ2=0.145, P=0.703>0.05), disease constitution through Fisher exact probability test (P=0.703>0.05), pre-operation cardiac functions and QRS duration. It shows that the base line of right ventricular outflow-tract pacing group and right ventricular apex pacing group is consistent and comparable.Through pairing t test, the pre-operation and post-operation results of right ventricular outflow-tract pacing group show no statistical significance of difference in left ventricular end-systolic diameter (LVEDD), left ventricular ejection fraction (LVEF), left ventricular fraction shortening (LVFS)(all the P values>0.05), while pre-operation and post-operation left ventricular end-diastolic diameter [(41.82±6.37) mm vs.(39.45±5.73) mm, t=2.6, P=0.017] of right ventricular outflow-tract pacing group has statistical significance. The post-operation left ventricular end-diastolic diameter is smaller than that before operation, shrinking the heart. The pre-operation and post-operation QRS duration [(109.09±24.63) ms vs.(134.95±12.86) ms, t=6.84, P<0.001)], which has statistical significance of difference, and the post-operation duration is wider than that before operation.(see Table4)The pacing threshold value of right ventricular outflow-tract pacing group after implanting spiral electrode is (0.86±0.3)V, and the reexamined pacing threshold value after operation is (0.67±0.16)V, t=2.85, P=0.01; the immediate wire impedance of right ventricular outflow-tract pacing group in the operation is (627.0±161.44) Ω, and the reexamined pacing wire impedance after operation is (389.59±150.55) Ω, t=4.25, P<0.001; the immediate R scope in operation is (10.76±1.82) mv, and the reexamined after operation is (8.62±2.52) mv, P=0.001; the difference has statistical significance. The immediate pacing threshold value, electrode impedance and R scope of right ventricular outflow-tract pacing group decrease after operation,(see Table5)Through pairing t examination, the pre-operation and post-operation statistical results of right ventricular apex pacing group show there is no statistical significance of left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVEDD), left ventricular ejection fraction (LVEF), left ventricular fraction shortening (LVFS), R scope and pacing threshold values. There is statistical significance of the discrepancy of pre-operation and post-operation QRS duration [(108.88±28.18) ms vs.(147.44±22.35) ms, t=4.47, P<0.001] and wire impedance [(765.88±184.64) ms vs.(405.13±84.66) ms, t=6.10, P<0.001]. QRS duration becomes wider in the pacemaker implantation of right ventricular apex pacing group than it was after the operation, and the wire impedance is higher in the pacing operation but declines after the implantation.(see Table5)With the two independent-sample t test of the difference values before and after operation of each examination indexes, the pre-operation and post-operation left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVEDD), left ventricular ejection fraction (LVEF), left ventricular fraction shortening (LVFS) of right ventricular outflow-tract pacing group and right ventricular apex pacing group, pre-operation and post-operation pacing threshold values, R scope, electrode impedance, the two independent-sample t test of the difference values of QRS duration, all the P values>0.05, the discrepancy has no statistical significance.But the discrepancy of QRS duration difference value [(134.95±12.86) ms vs.(147.44±22.35) ms, t=1.35, P=0.01] between right ventricular outflow-tract pacing group and right ventricular apex pacing group is statistically significant, indicating that the discrepancy has no statistical significance although both pacing methods can improve cardiac functions. The pacing parameters of the two pacing methods immediately decrease, so the discrepancy is not statistically significant. However, when QRS duration is broadened, compared with right ventricular apex pacing group, right ventricular outflow-tract pacing group has smaller broadening tendency, and to a certain extent QRS duration can reflect the left and right ventricular systolic synchronism, so right ventricular outflow-tract pacing group has an advantage in left and right ventricular systolic synchronism. There is one case of bladder bag infection in the right ventricular outflow-tract pacing group, and there is one case in the right ventricular apex pacing group that child patients who have low cardiac output after the correction operation of congenital heart disease die of cardiac failure due to myocardial ischemia after the implantation of permanent pacemaker.(see Table6、 Table7) Conclusions:1, Children’s pacemaker mode is affected by the weight.The children in Endocardial pacing group has the following characteristics, older, heavier, shorter hospital stay, less congenital heart disease and less pacing lead replacement times than the epicardial pacing group. Therefore conditional line endocardial pacing therapy in children should be implanted using endocardial pacing mode.2, The complications, pacemaker replacement times and pacing mode of endocardial and epicardial pacing are not significantly different.3, Endocardial pacing in the right ventricular outflow tract pacing in children’s application is safe and feasible.4, Right ventricular outflow tract pacing QRS duration shorter than the apical pacing, left ventricular systolic synchrony in the advantage.5, The right ventricular outflow tract pacing and ventricular apical pacing in postoperative systolic and diastolic function were compared with preoperative has improved, but no significant difference between the two.6, Right ventricular outflow tract pacing group immediately at the electrode implanted pacing thresholds, lead impedance, R-wave amplitude were reduced after review. Right ventricular apical pacing group’s pacing parameters is more stable. The difference was not statistically significant. |
PDF Full Text Request