Left ventricular mass and global wall thickness – prognostic utility and characterization of left ventricular hypertrophy

AIMS Cardiovascular magnetic resonance (CMR) can accurately measure left ventricular (LV) mass, which is associated with morbidity and mortality. Several measures related to LV wall thickness exist, with uncertain relative prognostic strength. We hypothesized that prognosis can be used to select an optimal measure of wall thickness for characterizing LV hypertrophy. METHODS AND RESULTS Subjects having undergone CMR were studied (cardiac patients, n=2543; healthy volunteers, n=100). A new measure, global wall thickness (GT, GTI if indexed to body surface area), and related measures, including mass/volume and mass/volume 2/3 , were calculated. GT was accurately calculated from LV mass and LV end-diastolic volume. Among patients with follow-up (n=1575, median follow-up 5.4 years), the most predictive measure of death or hospitalization for heart failure was LV mass index (LVMI) (hazard ratio (HR)[95% confidence interval] 1.16[1.12–1.20], p<0.001), followed by GTI (HR 1.14[1.09–1.19], p<0.001). Among patients with normal mass, volume, systolic function and absence of scar (n=326, median follow-up 5.8 years), the most predictive measure was GT (HR 1.62[1.35–1.94], p<0.001). GT and LVMI could characterize patients as having a normal LV mass and wall thickness, or concentric remodeling, concentric hypertrophy, or eccentric hypertrophy, and the three abnormal groups had worse prognosis than the normal group (p<0.05 for all). CONCLUSIONS LV mass is highly prognostic when mass is elevated (advanced disease), but global wall thickness is easily and accurately calculated, and adds value and discrimination amongst those with normal mass (early disease). The combination of these two measures can be used to characterize hypertrophy.