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.

Background: Predictors of Suboptimal reperfusion are still unclear. Aim: This study aimed to determine the factors that may indicate suboptimal reperfusion and short-term mortality in patients who were diagnosed with acute ST-segment elevation myocardial infarction (STEMI) and underwent primary percutaneous coronary intervention (pPCI). Patients and methods: This multicenter prospective comparative study, conducted at Benha University hospitals and National Heart Institute, included 400 patients (age<18 years and both sex) with acute STEMI, who were treated with PPCI. They were divided equally into 2 groups; suboptimal and optimal reperfusion groups (TIMI < III Vs.TIMI III respectively). Clinical data was collected. ECG, laboratory investigations, echocardiographic study, PPCI and 6 months follow up were done to all patients included. Results: This study showed that advanced age (60.4±8.2), family history of CAD, dyslipidemia, being diabetic, prolonged Pain to PCI time, higher random blood sugar (RBG) at the time of presentation, Killip class >1, heavy thrombus burden, prediltation, multiple stents insertion and longer stent length are predictors of the SOR after PPCI. While, Patients on long term beta blockers (BB) and angiotensin-converting enzyme inhibitor (ACEI) are less likely to develop SOR. Furthermore, patients with SOR are more likely to develop in-hospital arrhythmias, heart failure, acute mitral regurge and inhospital mortality. Additionally, it increases 6-months risk of reischemia and mortality. Conclusions: Predicting the occurrence of no-reflow following pPCI can be achieved by considering various factors, such as clinical data, laboratory results, angiographic features, and procedural characteristics. Heavy thrombus burden, prediltation, dyslipidemia, longer stent length, pain to PCI time and RBG >300 (mg/dL) at the time of presentation were found to be the most predictable variables to SOR. Long term use of BB and ACEI were found to be significant independent factors that decreased the likelihood of TIMI9h were considered the most predictable variables to mortality in no reflow.