1228 New predictors of sudden cardiac death in hypertrophic cardiomyopathy

Abstract

Abstract BACKGROUND Hypertrophic cardiomyopathy (HCM) is a heart disease characterized by hypertrophy of the left ventricular myocardium. HCM is the most common cause of sudden cardiac death (SCD) in young people and competitive athletes due to fatal ventricular arrhythmias. However, in most patients, HCM has a benign course. That is why it is of utmost importance to properly evaluate patients and identify those who would benefit from a cardioverter-defibrillator (ICD) implantation. The HCM SCD-Risk Calculator is a useful tool for estimating the risk of SCD. The parameters included in the model at evaluation are: age, maximum left ventricular (LV) wall thickness, left atrial (LA) dimension, maximum gradient in left ventricular outflow tract, family history of SCD, non-sustained ventricular tachycardia (nsVT) and unexplained syncope. Nevertheless, there is potential to improve and optimize the effectiveness of this tool in clinical practice. Therefore, the following new risk factors are proposed: LV global longitudinal strain (GLS), LV average strain (ASI) and LA volume index (LAVI). GLS and ASI are sensitive and noninvasive methods of assessing LV function. LAVI more accurately characterizes the size of the left atrium in comparison to the LA dimension. METHODS 252 HCM patients (aged 20-88 years, of which 49,6% were men) treated in our Department from 2005 to 2018, were examined. The follow-up period was 0-13 years (average: 3.8 years). SCD was defined as sudden cardiac arrest (SCA) or an appropriate ICD intervention. All patients underwent an echocardiographic examination. The medical and family histories were collected and ICD examinations were performed. RESULTS 76 patients underwent an ICD implantation during the follow-up period. 20 patients have reached an SCD end-point. 1 patient died due to SCA and 19 had an appropriate ICD intervention. There were statistically significant differences of GLS and ASI values between SCD and non-SCD groups; p = 0.026389 and p = 0.006208, respectively. The average GLS in the SCD group was -12.4% ± 3.4%, and -15.1% ± 3.5% in the non-SCD group. The average ASI values were -9.9% ± 3.8% and -12.4% ± 3.5%, respectively. There was a statistically significant difference between LAVI values in SCD and non-SCD groups; p = 0.005343. The median LAVI value in the SCD group was 45.7 ml/m2 and 37.6 ml/m2 in the non-SCD group. The ROC curves showed the following cut-off points for GLS, ASI and LAVI: -13.8%, -13.7% and 41 ml/m2, respectively. Cox’s proportional hazards model for the parameters used in the Calculator was at the borderline of significance; p = 0.04385. The model with new variables (GLS and LAVI instead of LA dimension) was significant; p = 0.00094. The important factors were LAVI; p = 0.000075 and nsVT; p = 0.012267. CONCLUSIONS The proposed new SCD risk factors were statistically significant in the study population and should be taken into account when considering ICD implantation.