不同右心室心尖部起搏百分比对心功能的影响

Effects of different cumulative percent of right ventricular apical pacing on cardiac function

目的探讨在不同心室起搏百分比（CUM％VP，即起搏心室率占总心室率的百分比）时长期右心室心尖部起搏（RVA）对基础心功能正常患者心室结构和心功能的影响。方法选取安装起搏器时基础心功能正常、因行起搏器更换和门诊复诊起搏器的患者为研究对象，CUM％VP≥85％组78例，CUM％VP≤40％组63例。以新发心力衰竭、死亡及左心室重构、功能受损为终点，比较2组之间的发生率；同时观察左心室舒张末期内径（LVEDD）、左心室射血分数（LVEF）、室间隔厚度（IVS）从基线至随访结束时的改变（ALVEDD、ALVEF、AIVS）。结果两次评估相隔的平均时间CUN％VP≥85％组为7．4年，CUM％VP≤40％组为7．7年。起搏前2组患者年龄、性别、总起搏时间、起搏模式、基础疾病及心脏超声指标等情况基本相似，差异无统计学意义（P均〉0．05）；随访结束时，CUM％VP≥85％组与CUM％VP≤40％组ALVEDD分别为（3．8±0．5）、（1．4±0．4）mm（t=4．540，P〈0．01），ALVEF分别为（-6．5±1．2）％、（-3．3±1．0）％（t=2．578，P=0．011），而AIVS比较差异无统计学意义；随访结束时2组均无死亡，CUM％VP≥85％组和CUM％VP≤40％组左心室重构、功能受损发生率分别为25．6％（20／78）、6．3％（4／36），差异有统计学意义（X^2=9．183，P=0．002）；新发心力衰竭发生率分别为10．3％（8／78）、1．6％（1／36），2组比较差异有统计学意义（X^2=4．383，P=0．036）。结论基础心功能正常患者长期右心室心尖部起搏（RVA）存在发生心室重构、功能受损和心力衰竭的可能，起搏时间越长、CUM％VP越高其发生风险越大。

Objective To evaluate the effect of permanent right ventricular apical （RVA） pacing in different cumulative percent of right ventricular pacing（ CUM% VP） on the heart function and cardiac ventricle structure in subjects with normal basic heart function. Methods Patients who had implanted pacemaker when heart function was still normal were recruited in the study while they revisited for replacement or examinations of implanted pacemaker at outpatient. According to different CUM% VP,patients were divided into group A（ CUM% VP≥ 85%, n = 78 ） and group B （CUM% VP ≤40%, n = 63 ） . The primary composite endpoint was defined as new-onset heart failure, death, left ventrieular （ LV ） dysfunction and remodeling. The occurrence of endpoints were compared between the two groups. The left ventrieular end-diastolic diameter （ LVEDD ） , left ventricular ejection fraction（LVEF） and interventricular septum（IVS） were measured through baseline and follow-up ,their absolute alterations （ △ LVEF,△ LVEDD and △ IVS ） were observed. Results The mean duration of two assessment was 7.4 years in group A and 7.7 years in group B, respectively. Before pacemaker implantation, there were no differences in age, sex, basic diseases, cardiac function and constituent ratio of pacemakers between the two groups. By comparing the outcomes of group A with those of group B at the end of follow up, we found that： △ LVEDD in group A was significantly larger than that in group B （ [ 3.8 ± 0. 5 ] mm vs [ 1.4 ± 0. 4] mm, t = 4. 540,P 〈 0. 01 ）,△ LVEF was （ - 6. 5 ± 1.2） % and （ - 3.3 ± 1.0 ） % in group A and B, respectively, with significant difference between the two groups （t = 2. 578, P 〈 0. 01 ）. There were no significant difference in AIVS between the two groups. No death occurred in both group at the end of follow up. The incidence of LV dysfunction and remodeling was 25.6% （20/78） in group A,which was significantly higher than that of 6. 3% （4/63） in group B（X^2 =9. 183 ,P =0. 002）. and the incidence of new-onset heart failure was 10. 3% （8/78） in group A,which was significantly higher than that of 1.6% （1/63） in group B （X^2 = 4. 383, P = 0. 036）. Conclusion Among patients with normal basic LV function who underwent permanent RVA pacing, there are potential risk in developing LV remodel, function damage and heart failure. The risk increases with the pacing time getting longer and CUM% VP getting higher.