0370 : Long-term cardiac prognosis and risk stratification in 260 adults presenting with mitochondrial diseases

Background The long-term cardiac prognosis of adults with mitochondrial diseases is unknown. Methods and Results Between January 2000 and May 2014, we retrospectively included in this study 260 consecutive patients (60% women) e18 years of age, [interquartile range (IQR) = 31 to 54], with genetically proven mitochondrial diseases, including 109 with mtDNA single large-scale deletions, 64 with the m.3243A>G mutation in MT-TL1, 51 with other mtDNA point mutations, and 36 patients with nuclear genes mutations. Cardiac involvement was present at baseline in 81 patients (30%). Single and multiple variable analyses were performed in search of predictors of major adverse cardiac event (MACE), and hazard ratios (HR) and 95% confidence intervals (CI) were calculated. Over a median follow-up of 7 years (IQR = 3.6 to 11.7), 27 patients (10%) experienced a MACE, defined as sudden death, death due to heart failure (HF), resuscitated cardiac arrest, 3rd degree atrioventricular block, sinus node dysfunction, cardiac transplantation, or hospitalization for management of HF. Patients with single large-scale mtDNA deletions or m.3243A>G mutations had the highest incidence of MACE. By multiple variable analysis, intraventricular conduction block (HR = 16.9; 95% CI: 7.2 to 39.4), diabetes (HR = 7.0; 95% CI: 2.9 to 16.7), premature ventricular complexes (HR = 3.6; 95% CI: 1.4 to 9.2) and left ventricular hypertrophy (HR=2.5; 95% CI: 1.1 to 5.8) were independent predictors of MACE. In patients with 0, 1, and e2 risk factors, the incidence of MACE was 1.7, 15 and 42% respectively. Conclusions Patients with mitochondrial diseases are at high risk of MACE, independently predicted by intraventricular conduction block, diabetes, ventricular prematurity and left ventricular hypertrophy.