| Cardiac pace - making technology is one kind means of therapying arrhythmias, which is difficult to be controlled by all drugs. Although some indicators, such as cardiac output, respiratory minute volume ( MV) , oxygen intaking energetic curve, exercise tolerence ( sub - maximal exercise and peak exercise) and so on, have been adopted to evaluate pacing therapy, at present, people have increasingly come to realize the importance of quality of life (QOL) referred to as evaluating indicator, which is " a state of complete physical, mental and social well - being and not merely the absence of disease or infirmity, including physical function, social interaction, psychologycal state and somatic sensation and so on,and reflecting patients health status being perceived,therefore the QOL is a scientific indicator of evaluating pacing therapy.Quite a few studies had demonstrated more beneficial effects of atrial synchronous (VDD or DDD)and rate adaptive ventricular pacing(VVIR) compared to fixed rate ventricular (VVI) with regard to exercise capacity and central hemo-dynamics. There are cardiovascular symptom relief during VDD pacing compared to VVI pacing,and during VVIR pacing compared to VVI pacing,At the meantime, there are more improving in the QOL during VVIR pacing compared to VVI,too. The symptom of patients with 3° AV block preserved normal sinus node function can be further relived and the QOL can be further improved during DDD pacing compared to VVIR pacing. However other studies indicated that there were not statistical difference in the QOL during DDD pacing compared to VVIR pacing. The QOL of patients can be somewhat improved with completed AV block or sick sinus node syndrome ( SSS) during DDDR pacing compared toDDD pacing or to VVIR pacing, however there were not statistical difference in the grade of cardiac function. The syncope symptom of patients with vascular syncope can be significantly improved during DDDR pacing compared to DDI pacing, however there were not statistical difference in the QOL. In conclusion, the difference of both cardiovascular symptomatology and the QOL among different pacing mode( DDD mode,DDDR mode and VVIR mode)would have been o-verall studied.Experimental Materials and Methods1. Study objectiveAll patients studied, who accepted permanent pacing therapy in the first affiliated hospital of China Medical University before July 30, 2004, corresponded with the standard as follows:Choosing standard;(1) possesse necessary symptom implanted permanent pacingmaker.(2)The patients are capability of finishing daily activity.(3)The patients are capability of finishing the studying follow - up.(4)DDDR pace -making group:In all patients,who were implanted DDDR pacemaker because of SSS,atrial sensed≤5% and ventricular sensed ≤5% (AS<5%,VS≤5%( 5) DDD pace - making group: All patients were implanted DDD pacemaker because of 3° AV conducting block , along with normal sinus node function.Deleting standard;The patients cannt finish activity demanded.In the study, we chose 24 patients, whose mean age is 57 years old, range 24 -75years old. 9 patients (4males, 5females) were implanted DDD pacemaker because of 3° AV conducting block with normal sinus node function. 14 patients (5males, lOfemales) were implanted DDDR pacemaker because of SSS with AS ≤5% and VS≤5%. 1 patient (male) were implanted DDD pacemaker because of SSS,along with hypertrophic cardiomyopathy(HCM).The mean period implanted were 13 months,range 2-25 months. All pacemakers implanted were activity sensed ( ACT) ones.2. Studying methodsThe study is a Perspective, randomived, Cross -over,Double blind one. The DDD type pacemaker was programmed randomly DDD mode or VVIR mode. The DDDR type pacemaker was programmed randomly DDDR mode, DDD mode or VVIR mode. Every programmed period was one month. Besides the above ar-rhymias,many patients accepted drug therapy because of other cardiovascular disease. In order to avoid bias brought about by drugs, therefore we had kept drug therapy unchanged during the study.Observing indicators;(1) Baseline characteristics: age, sex, cardiovascular disease history ( coronary heart disease, hypertation, cardiac surgery history, arrhymias history ) , the present status (the grade of cardiac function in the NYHA system, cardiovascular drug using history and symptom) and so on.(2)General experimental indicators; blood lipid,blood glucose, 12 lead E-lectrocardiogram (ECG) before and after pacemaker programmed.( 3 ) Follow - up studying evaluation; The QOL was evaluated by " Hacettepe Quality — of— life Questionnaire" and the cardiovascular symptom was evaluated by " the cardiovascular symptomatology of Karolinska Quality - of - life Questionnaire". Both questionnaire were self - evaluating, which can avoid bias to which operators subjective judgement lead.(4) Side - effects; Asked for patients to record side - effects during different pace - making mode.3. Statistical analysisQuantitative data are expressed as mean ± sd. All data about Both QOL and cardiovascular symptom ( along with their dimensions) were compared by paired sample t - test with SPSS11.5 statistical software. Test level a = 0. 05, P < 0. 05 was considered into significance. The null hypothesis was rejected beyond the 95% confidence level (CI).ResultsThe study was cross - over one and had kept drug therapy unchanged dur-ing following - up study, therefore there was no significant difference in the baseline characteristics between groups, including age, sex, cardiovascular disease history ( coronary heart disease, hypertation, cardiac surgery history, arrhymias history) , the present status (the grade of cardiac function in the NYHA system, cardiovascular drug using history) ,blood lipid,blood sugar,drug use and so on.1. Patient groups with 3 AV block and normal sinus node function.Both cardiovadcular symptom (table 1) and QOL( table 2) in patients with 3°AV conducting block and normal sinus node function were improved significantly during DDD pacing compared to VVIR pacing; At the meantime, some dimensions , including activity, physical symptom, work performance and general well — being were significantly improvemed, however there were not statistical significance in the other dimensions, including sleep function, appetite, sexual function and social participation. All patients preferred to DDD pacing period.2. Patient groups with SSS ( AS≤5% ,VS≤S5% ).Patients'cardiovadcular symptom in Patient groups with SSS (AS≤5% ,VS ≤5% ) were improved obviously during DDDR pacing or VVIR pacing compared to DDD pacing ( Shortness of breath, palpitation, dizziness, and chest pain were significantly improved while DDDR pacing; While VVIR pacing,shortness of breath, palpitation were significantly improved, however there were not statistical significance in dizziness,and chest pain. ) (table 3) ;At the meantime, the QOL were improved obviously (table4a 4b) ,some dimensions, including activity , physical symptom, work performance and general well - being were significantly improvemed, however there were not statistical significance in the other dimensions, including sleep function, appetite, sexual function and social participation. Patients'cardiovadcular symptom were improved significantly (table 3) during DDDR pacing compared to VVIR pacing, however the four dimentions werent exposed statistical significance (table 4a 4b) ;the QOL were improved significantly (table 4a 4b ) , some dimensions, including activity, physical symptom , work performance and general well - being were significantly improvemed, however there were not statistical significance in the others dimensions, including sleep function, appetite, sexual function and social participation. 10 patients preferred to DDDR pacing period, 4 patients preferred to both DDDR and VVIR pa-cing period,none preferred to DDD pacing period.3. Others1 patient, who were implanted DDD pacemaker because of SSS with HCM, appeared side - symptom at once while programmed DDD pacing to VVIR pacing, therefore we did not compared with two pacing mode.DiscussionIn order to determine that DDDR pacing, DDD ( VDD ) pacing and VVIR pacing influential degree to both cardiovascular symptom and QOL,we had studied 24 patients, 9 of who were implanted DDD pacemaker because of 3° AV block with normal sinus node function. 14 of who were implanted DDDR pacemaker because of SSS with AS ≤5% and VS≤5% ,1 of who was implanted DDD pacemaker because of SSS with HCM. Besides the arrhymias,many patients accepted drug therapy because of other cardiovascular disease. In order to avoid bias brought about by drugs, therefore we had kept drug therapy unchanged during the study.Patients'cardiovadcular symptom with 3° AV block and normal sinus node function were improved significantly during DDD pacing compared to during VVIR pacing,which corresponded with the outcome that Cecilia et al studied, and the QOL were improved significantly, in particular some dimensions including activity, physical symptom, work performance and general well - being were significantly improvemed. The reasons for above improvement could be as follows : 1. DDD pacing fulfill atrioventricular synchoronous compared to VVIR pacing. 2. DDD pacing possess the best adaptive rate, no doubt, which is complete physical compared to VVIR pacing.In Patient groups with SSS ( AS≤ 5% , VS≤ 5% ) , both cardiovascular symptom and QOL ( in particular activity, physical symptom, work performance and general well - being) were improved significantly during DDDR pacing or VVIR pacing compared to DDD pacing, the reasons for them is that DDDR pacing and VVIR pacing possesses better adaptive rate compared to DDD pacing. The reasons that the DDDR pacing relieve cardiovascular symptom and improvethe QOL compared to VVIR pacing could be DDDR pacing fulfill atrioventricular synchoronous compared to VVIR pacing.The reasons that 1 patient implanted DDD pacemaker because of SSS with HCM appeared side - symptom at once while programmed DDD pacing to VVIR pacing could be that the loss of atrioventricular synchoronous and decreasing of left ventricular diastolic end volume (LVEDV) aggravate left ventricular blot and decrease per stroke output of left ventricular.Some serious events, such as death of spouse, divorce, or being dismissed from work and so on, may influence patients' QOL, including sleeping, appetite, sexual function, even cardiovascular symptom. However, there were not any a-bove affairs in all patients during the study. Therefore, the outcome of study were not influenced by the bias that the above factors brought about in the QOL.The reasons for there were not consistent differences in some QOL parameters could be explanted as follow.-1. a relatively small sample size;2. a test instrument too insensitive to detect small differences ( for example sleep, appetite and so on) ;3. the shorter studing period that the patients couldnl completely passed throgh all events ;4. the patients'deliberatly concealing under certain history and value view condition and so on.In order to avoid self - heart rhythm influence on the QOL and cardiovascular symptom in the study,we choosed patients with SSS (AS≤5% ,VS≤5% ) , therefore, the number of patients chosen were small. In addition, although the cardiovascular symptomatology of Karolinska Quality - of - life Questionnaire had been applied for decades,It could not accurately reflected the frequency of symptom and the relative degree with activity degree, thus there is quite a few flaw. It is high time that we work out a more scientific evaluation scale with cardiovascular symptomatology.Conclusion1. In patients with 3° AV block and normal sinus node function, cardiovad-cular symptom were further improved signicantly and the QOL were further improved signicantly during DDD pacing compared to during VVIR pacing, there-... |
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