糖尿病兔心房电机械功能受损与心房颤动的关系

Relationship between atrial electromechanical function impairment and atrial fibrillation in alloxan-in- duced diabetic rabbits

目的应用组织多普勒超声心动图（DTE）评价四氧嘧啶诱导的糖尿病兔心房电机械功能，同时观察心房病理、电生理改变及心房颤动（房颤）易感性的变化。方法应用四氧嘧啶诱导成功糖尿病兔共8只，健康对照组8只，饲养8周，应用DTE测定心电图P波开始至心房各节段速度曲线上舒张晚期a’波开始的时间问期（Pastart）及心电图P波开始至DTE速度曲线上舒张晚期a’波峰值处的时间间期（Papeak）；建立Langendorff灌流的离体兔心脏模型，测量心房间传导时间（IACT）、心房各点有效不应期（AERP）、AERP的离散度（AERPD）、应用短阵快速刺激观察房颤诱发情况，应用天狼猩红染色评价左心房纤维化情况。结果与对照组比较，糖尿病组兔左心房前后径明显增大[（6．8±0．6）mm对（8．3±0．6）mm，P〈0．01]，室间隔增厚[（1．9±0．2）mm对（3．0±0．5）mm，p〈0．01]；左心房侧壁Pastart及右心房Pastart延长【分别为（40．5±12．9）ms对（60．4±20．4）ms，P〈0．05；（59．8±20．1）ms对（83．0±11．0）ms，P〈0．05）]；IACT延长[（37.6±8．9）ms对（27．7±2．1）ms，P〈0．01）]，房颤诱发率升高（6／8对1／8，P〈0．05）；病理检查提示糖尿病组左心房心肌间质明显纤维化。两组房间隔处Pastart，左心房后壁Pastart及Papeak均与IACT显著相关。结论糖尿病兔心房电机械功能受损，与心房肌纤维化、心房间电传导延迟有关，可能是糖尿病发生房颤的机制之一。

Objective The aim of this study was to evaluate the potential relationship between atrial electromechanical function measured by Doppler tissue echocardiography（ DTE）, atrial histological and electro- physiological changes and atrial fibrillation（AF） inducibility in alloxan-induced diabetic rabbits. Methods In 8 alloxan-induced diabetic rabbits （DM）and 8 healthy controls, we measured atrial electromechanical coupling start intervals（Pastart） and P-a＇ peak intervals（Papeak） by DTE;DTE a＇-wave duration and the total electrome- chanical activity（TEMA）. Isolated Langendorff perfused rabbit hearts were prepared to evaluate interatrial con- duction time（ IACT）, atrial refractory effective period（AERP） and atrial refractory effective period dispersion （AERPD） and vulnerability to AF. Sirius-Red staining was used to evaluate atrial fibrosis. Results Compared with controls, left atrial diameter（ LAD）, interventricular septum thickness（ IVST）, left atrial（LA） lateral wall Pastart （latPastart） and right atrial wall Pastart （raPastart） were increased in diabetic rabbits [ LAD （ 8. 3±0. 6） nun vs （6. 8 ＋0. 6） mm, P〈O. O1 ） ; IVST [ （ 3. 0± 0. 5 ） mm vs （ 1.9±0. 2 ） mm P〈0. -1 ） ; latPastart [ （40.5 ±12. 9 ） ms vs. （60.4±20. 4）ms P〈0. 05 ） ;raPastart [ （59. 8 ±20. 1 ） ms vs. （83.0± 11.0 ） ms P〈0. 05 ） ）. IACT was pro- longed in diabetic rabbits compared with controls[ （37.6±8. 9）ms vs（27.7±2. 1 ）ms P〈0.01 ））. Inducibility of AF in diabetic group was significant higher than controls （6/8 vs 1/8, P〈0. 05 ）. Inter-atrial septum （IAS） Pastart, LA posterior wall Pastart and LA posterior wall Papeak were correlated with IACT. Extensive interstitial fibrosis was observed in the DM group （P 〈0. 01 ）. Conclusion Atrial electromechanical function was im- paired in diabetic rabbits, which may relate to atrial fibrosis and interatrial electrical conduction delay, and may serve as an important substrate for the development of AF.