Usefulness of the MADIT-ICD Benefit Score in a S-ICD Patient Cohort

Background : The subcutaneous ICD (S-ICD) is used in an increasing number of patients for primary and secondary prevention of sudden cardiac death. Decision-making in primary prevention is not always trivial and many clinical scenarios are not reflected in current ICD guidelines. To help evaluating the patient’s individual risk, a new score trying to predict the benefit of an ICD implantation for primary prevention, the MADIT-ICD benefit score, which tries to predict occurrence of ventricular arrhythmias and non-arrhythmic death, has been proposed. We therefore aimed at examining its usefulness in a large single centre register of S-ICD patients Methods and results : All S-ICD patients with a primary preventive indication for ICD implantation from our large single centre database were included in the analysis (n=173). During a follow-up of 1227±978 days 27 patients developed sustained ventricular arrhythmias, while 6 patients died for non-arrhythmic reasons. Occurrence of ventricular arrhythmias could not sufficiently be predicted by the MADIT-ICD VT/VF score ( p =0.3) in patients with (n=142, p =0.19) as well as patients without structural heart disease (n=31, p =0.88). However, there was a significant correlation for patients with ischemic cardiomyopathy (ICM) (n=29, p =0.04). Only one parameter (non-sustained ventricular tachycardia) was significantly associated with sustained ventricular arrhythmias ( p =0.02). Of note, non-arrhythmic death could effectively be predicted by the proposed non-arrhythmic mortality score as part of the benefit score ( p =0.001, r =0.3) also mainly driven by ICM patients. Age, diabetes mellitus, and a BMI <23 kg/m 2 were key predictors of non-arrhythmic death implemented in the score. Conclusion : The MADIT-ICD benefit score adds a new option to evaluate expected benefit of ICD implantation for primary prevention. However, in our S-ICD cohort, the only group in which the score worked properly for prediction of sudden and non-sudden death were ICM patients, so that a larger validation in more heterogeneous cohorts in mandatory to claim general validity for this score in risk stratification for primary preventive ICD implantation.