Abstract 14833: Chronic Cardiac Injury Identifies a Malignant Left Ventricular Hypertrophy Phenotype in the General Population
Background: The interaction between left ventricular hypertrophy (LVH) and chronic cardiac injury, as reflected by very low but detectable circulating levels of cardiac troponin T (cTnT), on outcomes in the general population is unknown.
Methods: Left ventricular (LV) mass was measured by MRI and cTnT by a highly sensitive assay (Roche Diagnostics) in individuals with LV ejection fraction ≥40%, eGFR ≥60 mL/min/1.73 m2, and without clinical heart failure (HF) enrolled in the Dallas Heart Study, a multiethnic population-based cohort study. LVH was defined as LV mass/body surface area ≥89 g/m2 in women and ≥112 g/m2 in men. Participants were placed into 4 categories based on the presence of LVH and detectable cTnT (≥3 ng/L). The primary outcome of incident HF or cardiovascular (CV) death was determined through a median 8.1 years of follow-up.
Results: Of 2413 participants meeting study criteria (mean age 44; 56% women; 48% black), 223 (9.2%) had LVH and 590 (24.5%) had detectable cTnT. 102 (4.2%) participants had both LVH and detectable cTnT (+LVH/+cTnT) and were older; more likely to be male and black; with more hypertension, diabetes, and CV disease compared with those with neither or only 1 phenotype (p<0.0001 for each). The cumulative incidence of HF or CV death was 20.6% in the +LVH/+cTnT group compared with 1.1%, 3.9%, and 5.8% in the -LVH/-cTnT, -LVH/+cTnT, and +LVH/-cTnT groups, respectively (p<0.001 for each, Figure). In multivariable analysis, +LVH/+cTnT was associated with a marked increase in the risk for HF or CV death (HR 3.9, 95% CI 2.1 - 7.2 vs. neither or only 1 phenotype) and was the single strongest predictor in this population (X2=19 vs. X2<12 for other covariates). A highly significant interaction was observed between LVH and cTnT for the primary outcome (pinteraction=0.0005).
Conclusions: Circulating cTnT is a powerful marker of chronic cardiac injury in individuals with LVH and identifies a sub-phenotype at extremely high risk for HF and death.
- © 2012 by American Heart Association, Inc.