1.) Preoperative comparison of patient characteristics
The analysis of the three groups (SR, EL, SI) showed significantly younger patients in the SR group, but in terms of gender and body dimensions, an equal distribution was observed throughout the entire patient population. The analysis of preprocedural parameters did not reveal any significant group-specific differences, but a detailed examination of the specific group data indicated tendencies. Patients in the SI group had the lowest New York Heart Association (NYHA) classification of 2.4 and American Society of Anesthesiologists (ASA) classification of 3.0 and the lowest proportion of patients with diabetes (23.2%). They also showed the lowest level of renal dysfunction (creatinine 1.3 mg/dl; glomerular filtration rate (GFR) 78.8 ml/min/1.7), had the lowest incidence of coronary heart disease (45.5%), and the least frequent percutaneous coronary interventions (PCI) (21.9%) prior to surgery. In contrast, patients in the EL group had a higher NYHA class (2.5), the highest ASA class (3.4), and the lowest GFR (62.1 ml/min/1.7) compared to the other groups. The highest percentage of arterial hypertension (82.1%) was also found in this group, as well as the highest incidence of coronary heart disease (64.3%), which was also reflected in the highest number of PCIs (39.3%) and cardiac surgeries (42.9%) prior to lead extraction. The SR group showed the highest NYHA class (2.6) and second-highest ASA class (3.3), the highest creatinine level (1.6mg/dl), the second-worst GFR value (66.6 ml/min/1.7), and the highest percentage of diabetics (34.8%). Unexpectedly, this group had the highest left ventricular ejection fraction (LV-EF) of all groups at 44.7% (Tab. 1).