Abstract Background The number of elderly patients referred for electrophysiological study (EPS) and catheter ablation (CA) is increasing. These patients are thought to have more complications due to age and comorbidity. Purpose The aim of our study was to evaluate the safety (EPS and CA) and acute success (CA) in a group of elderly patients (age ≥75 years old). Methods Between August 2020 and September 2023, consecutive elderly patients (32.7% older than 80 years) underwent EPS alone or EPS and CA at our center. Left atrial thrombus was ruled out performing transesophageal echocardiography when indicated. Anticoagulation (ACO) was not interrupted. Femoral veins, arteries and transeptal punctures were performed under ultrasound guidance. A navigation system was used for all CA procedures, except for pulmonary vein isolation, which was performed with a cryoballoon. We analysed procedural complications related to EPS and CA and the acute success of CA procedures. Results A total of 104 patients undergoing EPS±CA (79.9±4.6 years, 41.3% female, 75% HTA, 67.3% diabetes type 2, 19.4% COPD, 20.2% chronic renal disease, 25% structural heart disease, CHA2DS2VasC score 3.6±0.8, IMC 27.3±4.5 kg/m2, weight 72.3±13.6 kg, LVEF 52.7±10.8%, 31% history of atrial fibrillation (AF), 47.1% on ACO, 38.5% bundle-branch block, 34.6% first-degree atrioventricular block, 4.8% implanted pacemaker or ICD) were included. Indications for referral (Figure 1) were typical atrial flutter (TAF, 34.6%), atrioventricular nodal reentrant tachycardia (AVNRT, 26.9%), study of syncope (11.5%) atypical atrial flutter or atrial tachycardia (AAF/AT, 10.6%), AF (8.6%, 6 patients for AV node ablation, 3 for pulmonary vein isolation), ventricular tachycardia or ectopy (VT or VE, 5.7%), orthodromic reentrant tachycardia (ORT, 1.9%). 2 patients had TAF and AVNRT, treated in the same procedure. Acute success was achieved in 100% of AF, 94.6% of TAF, 89.6% of AVNRT, 66% of VT/VE, 50% of ORT, 45% of AAF/AT. There were 4 complications (2.9%) in 3 patients, all during the CA procedure: an AV block during an AVNRT ablation, another AV block during an ischaemic septal VT ablation, a femoral artery pseudoaneurism in the same patient (femoral artery approach), and a dislocation of the electrodes from a previous pacemaker during an AT ablation. None of the patients undergoing EPS alone had complications. Weight was the only variable associated with the development of complications (mean difference= -19.8, 95% CI(-38.9-0.7); p=0.04), being higher in those with than in those without complications (91.5±2.2 vs 71.6±13 Kg),(Table 1). Conclusions EPS and CA procedures in elderly patients with multiple comorbidities are safe and effective. Acute success and complication rates of CA procedures are substrate-dependent and similar to those reported in the literature for younger patients. We conclude that age is not a barrier to the study and treatment of arrhythmias.