Abstract: To investigate the value of QRS wave amplitude and duration in the prediction of cardiac function after right ventricular septum pacing. Methods：82 patients with high or complete atrioventricular block and implanted permanent pacemaker were enrolled. The data of ventricular pacing, electrocardiogram and Echocardiography were followed up for 1 year. Excluding ventricular pacing ratio of less than 90% and pacemaker abnormal work, the final selection of 62 patients, in accordance to X-ray and the position of patients’ ventricular electrode tip, the patients are divided into there groups，called low-interventricular septum(22 cases), middle-interventricular septum(21 cases) and high-interventricular septum(19 cases) .The total amplitude of chest lead QRS wave (ΣQRSAV),the total amplitude of chest lead QRS wave starting at 0.04sec amplitude (ΣQRSAV0.04), QRS wave duration, pacing QRS wave depolarization to R wave peak duration(DR)and depolarization peak to depolarization duration (RE)and left ventricular ejection fraction (LVEF)were compared, through the analysis of the indicators to explore the possible factors of cardiac changes after right ventricular septum pacing , to seek the right ventricular ventricular septum position of the best pacing site. Results: There was no significant difference between baseline data such as age, sex, primarydisease and EF. Compared with the low-interventricular group, the middle group is with largerΣQRSAV, largerΣQRSAV0.04, shorter QRS duration, shorter DR time, smaller EF, but there was no statistics meaning in EF. Compared with the high-interventricular group, the middle group is withthe shorter QRS duration, larger ΣQRSAV, larger ΣQRSAV0.04, shorter DR and higher EF . There was no statistically difference between the low and high groups. There was no significant difference in RE time between the three groups. The QRS duration and ΣQRSAV had a significant effect on LVEF (P <0.05), and the effect of QRS duration on LVEF was greater than that of ΣQRSAV. There was a significant correlation between QRS duration and ΣQRSAV (r = -0.742, P <0.05). (R = 0.973, r = -0.709, P <0.05). (P <0.05), and there was a significant correlation between ΣQRSAV0.04 and QRS duration 0.05); ΣQRSAV0.04, DR had a significant correlation withΣQRSAV (r = 0.828, r = -0.745, P <0.05), RE time had a small correlation withΣQRSAV and QRS duration (r = -0.423, r = 0.683,P <0.05); Conclusion:Compared with low and high groups ,right ventricular middle-interventricular septum pacing has better heart function. QRS duration,ΣQRSAV ,ΣQRSAV0.04, DR duration may be used as indicators to guide right ventricular implantation and monitor postoperative heart function.