Slew Rate As a Predictor for Optimal Lead Fixation

The goal of this observational study is to identify the most reliable electrical parameter measured at the time of implantation that can predict optimal lead fixation and long-term lead performance in patients undergoing transvenous pacemaker or implantable cardioverter-defibrillator (ICD) implant. The main questions it aims to answer are: * Is there a correlation between the slew rate measured at the time of lead implantation and the sensing measured at the 12-month follow-up? * Is there a correlation between all electrical parameters recorded at implantation (including slew rate, current of injury, acute sensing, acute impedance, and acute pacing threshold) and the electrical parameters assessed at 12 months post-implantation (specifically chronic sensing, chronic impedance, and chronic pacing threshold)? Participants will undergo regular follow-up evaluations, with device interrogation visits scheduled at 1 and 12 months post-implantation as part of routine clinical care.