Background: Electrophysiology (EP) programs that involve specialized nurses and advanced practice providers (APPs) have a positive impact on patient outcomes, leading to improved safety, reduced complications, better patient education, and increased efficiency. Cardiac electrophysiological study is a diagnostic test used to evaluate the heart's electrical conduction system and diagnose the abnormal heartbeats. Aim of the study: To evaluate the effect of providing a designed nursing care program on selected outcomes of the critically ill patients undergoing cardiac EPS. Research design: A quasi-experimental research design was utilized in the current study (pre‐test and post‐test). Sample: purposive sample of 60 adult (M&F) critically ill patients who met the inclusion criteria. Setting: The study was conducted in Critical Care Department Cairo university hospitals. Research hypotheses. Four research hypotheses were formulated in the current study. Tools: Five tools were utilized to collect data pertinent to the study T1: Demographic & medical data sheet T2: State–Trait Anxiety inventory (STAI) assessment Sheet T3: Pre/Post Nursing care program knowledge questionnaire T4: Observational checklist (5parts) T5: Patient outcomes assessment & complications sheet Results:- Majority of the (S&C)subject were males (60.0%).All four research hypotheses were supported as follows; Knowledge Improvement (𝑯𝟏): The study group's mean knowledge scores increased significantly from 6.80 ±2.25 pre-program to 35.40 ±0.97 post-program, while control group scores remained low (6.07 ±1.95 vs. 6.03 ±1.50 ), indicating a high-impact educational intervention. Practice Improvement (H2): Mean practice scores for the study group showed significant improvement (43.47 ±3.31 pre-program vs. 56.66 ±5.87 post-program). The control group showed no significant improvement (44.65 ±3.93 vs. 45.4 ±3.74). Anxiety Reduction (𝑯𝟑): State-Trait Anxiety Inventory (STAI) results indicated a significant decrease in anxiety for the study group. Post-intervention, study group state anxiety dropped (39.86 ±6.06) compared to the control group (42.76 ±8.17). Furthermore, severe anxiety was eliminated in the study group (0.0 %) compared to 6.6% in the control group. Patient Outcomes (H4): The study group exhibited better clinical outcomes, specifically reduced complications and shorter hospital stays. Additionally, the intervention resulted in no readmissions and improved self-care practice & reduced anxiety levels. Conclusion: The current study showed better patients’ outcomes such as lesser complications, hospital stay, Anxiety level, with no death or readmission &with significant improvement of patients knowledge and self- care practices scores after intervention, Recommendations: Continuous enrichment of the critical ill patients’ education is vital to improves adherence to treatment, better self-care practice , reduces anxiety level as well as complications, and ultimately leads to improve patients’ outcomes. improves adherence to treatment, better self-care practice, reduces anxiety level as well as complications, and ultimately leads to improve patients’ outcomes.