Their Qrs Wave Width On The Cardiac Function Of Patients With Ventricular Pacing, Rely On The Predictive Value

Part I Effects of chronic right ventricular apical pacing on cardiac structure and function in pacing-dependent patients[Objective] To investigate the effects of chronic right ventricular apical (RVA) pacing on cardiac structure and function in pacing-dependent patients.[Methods] In this study,42patients with third degree atrioventricular block who underwent pacemaker implantation in our center form Jan2003to Dec2005were enrolled. We retrospectively investigated the impact of chronic right ventricular apical pacing on cardiac structure and function in patients dependent on pacing. The12-lead electrocardiography, echocardiography and clinical conditions were recorded for every patient before the implantation and during the follow-up. The12-lead electrocardiography and cumulative pacing rate were also obtained within5postoperative days and at each follow-up visit.[Results] A total of42patients with a high average right ventricular pacing rate of100%(98.8%-100%) were included, averagely aged63.7±15.7years. After77.3months of follow-up, the overall left ventricular ejection fraction (LVEF) decreased significantly from63.80±5.06%to57.13±11.43%(p>0.001). Meanwhile, left atrial diameter (LAD) statistically increased from36.02±5.81mm to39.64±6.80mm (p<0.001) and left ventricular end-diastolic diameter (LVEDD) enlarged from49.10±4.46mm to52.45±7.38mm (p>0.001).[Conclusion] Chronic RVA pacing leads to deterioration of LV systolic function and cardiac remodeling. Part II Preoperative intrinsic QRS duration is a valuable predictor of left ventricular function deterioration in pacing-dependent patients[Objective] To explore the predictive value of preoperative intrinsic QRS duration for left ventricular function deterioration in patients dependent on right ventricular apical (RVA) pacing.[Methods] In this study,42patients with third degree atrioventricular block who underwent pacemaker implantation were retrospectively analyzed.22patients with left ventricular ejection fraction reduction (ALVEF)≥5%after pacing (LV function deterioration group) and20patients with ALVEF<5%after pacing (non-LV function deterioration group) were enrolled to investigate the possible reasons and predictors for the cardiac function deterioration. The12-lead electrocardiography, echocardiography and clinical conditions were recorded for every patient before the implantation and during the follow-up. The12-lead electrocardiography and cumulative pacing rate were also obtained at each follow-up visit.[Results] All the recipients including22patients of LV function deterioration group and20patients of non-LV function deterioration group were operated in Receiver-Operating Curve (ROC). And the ROC showed preoperative intrinsic QRS duration (IQRSd)≥110ms could distinguish LVEF deterioration or not (AUC=0.683,95%CI0.513～0.853, sensitivity=68.2%, specificity=80.0%, p=0.043). Kaplan-Meier analysis revealed that LVEF decreased after pacing statistically earlier in patients with IQRS>110ms than that in patients with IQRS<110ms(81.7±3.7months vs.96.6±6.2months) and the rate was higher (78.9%vs.30.4%, χ2=5.873, p=0.015,p=0.015). COX regression analysis indicated that only IQRSd≥110ms was the independent predictor of LV systolic function decrease (RR2.82,95%CI1.14～6.96, p=0.025). Old age (age>65years), gender, diabetes, hypertension, coronary heart disease, atrial flutter/atrial fibrillation(AF), complete left bundle branch block(CLBBB), complete right bundle branch block (CRBBB), pacing mode(DDD/VVI) and wide postoperative pacing QRS duration (PQRS≥150ms) and could not predict LVEF decline (p>0.05).[Conclusion] In patients with IQRSd≥110ms, deterioration of LV systolic function appears after chronic right ventricular apical pacing and the rate is higher. IQRS>110ms is the independent predictor of LVEF reduction in patients dependent on right ventricular apical pacing.