The SHIFT model combines clinical, electrocardiographic and echocardiographic parameters to predict sudden cardiac death in hypertrophic cardiomyopathy

Abstract

Introduction: Limitations have been pointed out in the clinical risk prediction model for sudden cardiac death (SCD) of the European Society of Cardiology (ESC), which is recommended for hypertrophic cardiomyopathy (HCM) patients. The aim of this study was to determine the SCD risk of the HCM patients enrolled in a Portuguese nationwide registry and to develop a new SCD risk prediction model applicable to our population.

Methods and results: The cohort consisted of 1022 patients (mean age 53.2±16.4 years, 59% male) enrolled in a Portuguese national HCM registry. During the follow-up period (median five years), 19 patients (1.9%) died suddenly or had aborted SCD or appropriate implantable cardioverter-defibrillator (ICD) shock therapy. Through a Cox proportional hazards model, four variables were independently associated with SCD or equivalent: unexplained Syncope, Heart failure signs, Interventricular septum thickness ≥19 mm and FragmenTed QRS complex. These predictors were included in the SHIFT model and individual risk probabilities of SCD at five years were estimated. This model was internally validated using bootstrapping. The C-index of the SHIFT model was 0.81 (95% CI: 0.77-0.83) and the C-index of the ESC model (performed in a subgroup of 349 HCM patients) was 0.77 (95% CI: 0.73-0.81) (p=0.246).

Conclusion: The SHIFT model may potentially provide prognostic value and contribute to the clinical decision-making process for ICD implantation for primary prevention of SCD.

Keywords: Hypertrophic cardiomyopathy; Miocardiopatia hipertrófica; Modelo de risco; Morte súbita cardíaca; Risk model; Sudden cardiac death.