76 Late gadolinium enhancement fibrosis burden and sudden cardiac death risk stratification in hypertrophic cardiomyopathy: a single-centre retrospective analysis

Background Cardiac magnetic resonance imaging (CMRI) with late gadolinium enhancement (LGE) is increasingly used to quantify myocardial fibrosis in hypertrophic cardiomyopathy (HCM). This can assist in refining sudden cardiac death (SCD) risk stratification and guiding management. International guidelines differ in recommendations for incorporation of LGE burden in SCD risk stratification. This study reviews the reporting of LGE burden, and compares SCD risk from AHA and ESC calculators.Methods Retrospectively reviewed data for 38 HCM patients from a tertiary centre out-patient clinic. CMRI reports reviewed, SCD risk factors (family history, syncope, ventricular arrhythmias, maximal LV wall thickness, LVOT gradient) were extracted, and ICD status was recorded. Data analysed using Microsoft Excel, mean values compared using paired t-test; association tested using the chi-square test.Results Of the 38 patients, 90% had a CMRI report available. Percentage LGE fibrosis was reported in four cases, LGE fibrosis was described as mild in 62% (n=20) of cases, and severe in 22% (n=7). Mean LV wall thickness was 18.5mm (95% CI 16.9;20.2mm). ICDs were implanted in 24% (n=9). Mean AHA and ESC 5-year SCD risk were 2.8% and 2.7% respectively, paired t-test demonstrated that the difference was not statistically significant (p=0.06). No cases of cardiac arrest were documented during follow-up; two patients with ICDs had appropriate therapies.Conclusions In this single-centre cohort, LGE fibrosis on CMRI was frequently reported, however the reporting of LGE as a percentage was less common. While LGE does not impact the AHA 5-year predicted SCD risk, the AHA 2024 guidelines would recommend consideration of an ICD in patients with extensive LGE (>15%). Our data demonstrates that current CMRI reporting without specific LGE percentages can make incorporating these recommendations challenging. These findings underscore the need for standardized LGE reporting, particularly if it is to be considered in risk stratification for ICD implantation.