Discrepancy between International Guidelines on the Criteria for Primary Prevention of Sudden Cardiac Death in Hypertrophic Cardiomyopathy

Low Agreement Among Guidelines for Primary Prevention Implantable Cardioverter-Defibrillator Recommendations in Hypertrophic Cardiomyopathy

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.

Arrhythmic risk stratification in ischemic, non-ischemic and hypertrophic cardiomyopathy: A two-step multifactorial, electrophysiology study inclusive approach

Annual arrhythmic sudden cardiac death ranges from 0.6% to 4% in ischemic cardiomyopathy (ICM), 1% to 2% in non-ischemic cardiomyopathy (NICM), and 1% in hypertrophic cardiomyopathy (HCM). Towards a more effective arrhythmic risk stratification (ARS) we hereby present a two-step ARS with the usage of seven non-invasive risk factors: Late potentials presence (≥ 2/3 positive criteria), premature ventricular contractions (≥ 30/h), non-sustained ventricular tachycardia (≥ 1episode/24 h), abnormal heart rate turbulence (onset ≥ 0% and slope ≤ 2.5 ms) and reduced deceleration capacity (≤ 4.5 ms), abnormal T wave alternans (≥ 65μV), decreased heart rate variability (SDNN < 70ms), and prolonged QT_c interval (> 440 ms in males and > 450 ms in females) which reflect the arrhythmogenic mechanisms for the selection of the intermediate arrhythmic risk patients in the first step. In the second step, these intermediate-risk patients undergo a programmed ventricular stimulation (PVS) for the detection of inducible, truly high-risk ICM and NICM patients, who will benefit from an implantable cardioverter defibrillator. For HCM patients, we also suggest the incorporation of the PVS either for the low HCM Risk-score patients or for the patients with one traditional risk factor in order to improve the inadequate sensitivity of the former and the low specificity of the latter.