Sudden cardiac death (SCD) risk stratification and primary prevention implantable cardioverter-defibrillator (ICD) recommendations are based on differing strategies for hypertrophic cardiomyopathy (HCM). This study aimed to evaluate the impact of the 2023 European Society of Cardiology (ESC) guidelines on the 2014 ESC and the 2024 American Heart Association (AHA)/American College of Cardiology (ACC) systems in terms of primary prevention ICD recommendations for HCM. A cohort of 200 patients with HCM in Brazil was assessed for SCD risk profile according to current guidelines. The agreement for primary prevention ICD recommendations was evaluated among different strategies. SCD and appropriate shock were defined as the end points. Among the 200 patients, 63 (31%) received a primary prevention ICD, with 10 (15.8%) receiving appropriate shocks. Low agreement was found among the guidelines (Fleiss’ kappa 0.340, 95% confidence interval [CI] 0.286 to 0.395, p <0.001). The European systems showed moderate agreement. The 2024 AHA/ACC algorithm placed 58% of patients in class IIa, whereas only 29% achieved this recommendation with the 2023 ESC model. The end points occurred in 8% of patients over 9.4 ± 6.5 years. The 2014 ESC guidelines had the highest accuracy (77%, 95% CI 71 to 83) and negative predictive value (96%, 95% CI 90 to 98) in detecting patients in class IIa with primary end points. However, all guidelines showed a low positive predictive value. The 2024 AHA/ACC guidelines classified the largest proportion of patients (81%) with the primary end point as class IIa. Low agreement was found among guidelines regarding primary prevention ICD recommendations in HCM, particularly between the 2023 ESC and 2024 AHA/ACC systems.