A Follow-Up Study About The Influence Of QRS Duration On Cardiac Function Of Pacemaker-Dependent Patients

Objective To observe the influence of paced QRS duration on cardiac function of pacemaker-dependent patients.Methods 112 patients with third-degree atrioventricular block receiving right ventricular pacing were enrolled. The paced QRS duration was obtained after pacemaker implantation,and the patients were divided into two groups based on a cut-off value of paced QRS duration 190ms:group A(QRS<190ms) and group B(QRS≥190ms).Clinical assessment and cardiac Doppler ultrasound were performed at baseline and during follow-up period.The primary end point is pronounced decreasing of cardiac function.Those cardiac function-influenced factors with p value less than 0.1 screened from single-factor analysis were studied by multiple logistic stepwise regression analysis.Results During a mean of 45.46±23.00 months, the cardiac function of 40 paients(28.57%) was decreased remarkably.And the incidence of group B was more than that of group A(66.67% vs 22.27%, p=0.0004).The paced QRS duration of patients with cardiac function declined was longer than that of the patients without cardiac function declined(176.58±22.71 vs 159.74±20.23, p<0.0001).The result of multiple logistic stepwise regression analysis showed that prolongation of paced QRS duration,enlargement of left ventricular,declined eject fraction,left bundle branch block,age and the time of pacing are the risk factors of decreased cardiac function of pacemaker-dependent patients.Conclusion Prolongation of paced QRS duration is a risk factor of decreased cardiac function and heartt failure,and it can predict the decline of cardiac function of pacemaker-dependent patients. As well as the paced QRS duration,enlargement of left ventricular,declined eject fraction,left bundle branch block,age and the time of pacing are the risk factors of decreased cardiac function of pacemaker-dependent patients.