Background: Unnecessaryright ventricular (RV) pacing leads to cardiac dyssynchrony and increases the risk of developing permanent atrial fibrillation. Minimizing RV pacing by specefic algorithms decreases the AF risk. Aim and objectives: Our objective was to study the effect of pacemaker algorithms on atrial fibrillation progression. Subjects and Methods: Patients with dual chamber (group A) and single chamber (group B)pacemakers were included in the study. Patients with history of AF at the time of pacemaker implantation were not included in the study. The relation between pacemaker parameters and AF development was monitored. Result: Group A showed that RV pacing percentage had high significance for developing AF with P value P <0.001, also A pacing had high significance for developing AF with P value <0.001 and VIP mode OFF there was high significance of developing AF with P value <0.001.As regards group B RV pacing (%) had high significant risk for developing AF with p value<0.001,Also hysteresis off had high significant risk for developing AF with p value<0.005. Conclusion: Reducing unnecessary RV pacing in single and dual chamber pacemakers is assossiated with decreasing the risk of AF.