Evaluation of concentric left ventricular geometry in humans - Evidence for age-related systematic underestimation

There might be limitations in identifying concentric left ventricular (LV) geometry by ratio of diastolic posterior wall thickness (WTp) to cavity radius, defined as relative wall thickness (RWTp). This study has been designed to evaluate age effects on RWTp. WTp, mean of septal thickness and WTp (WTm), and cavity radius were cross-sectionally evaluated in 766 1- to 85-year-old, normotensive, nonobese subjects and 331 hypertensive Italians (used as a test series). RWTp greater than or equal to 0.43 defined "traditional" concentric LV geometry. The ratios WTm/radius (RWTm) and RWTp increased by 0.005 and 0.006 per year of age in the age stratum up to 17 years and by 0.002 in the older age stratum (18 years or older; all P < 0.0001). Thus, RWTm and RWTp were normalized to average age in both age strata (10 and 46 years) by age-specific regression coefficients. The 90th and 95th percentiles of age-normalized RWTp or RWTm were 0.40 and 0.42 or 0.41 and 0.43, respectively, in adults and 0.36 and 0.39 or 0.36 and 0.38, respectively in young subjects. In hypertensive subjects, traditional RWTp cutoff identified 74 subjects (22%) with concentric LV geometry; by 95th or 90th normal percentiles, normalized RWTm identified 112 (34%), or 149 (45%) subjects with concentric LV geometry, and normalized RWTp 29% and 39%, respectively ( all P < 0.0001 versus unadjusted RWTp). Thus, prevalence of concentric LV geometry increases with age-normalized RWT. Accordingly, we suggest that concentric LV hypertrophy be defined by coexistence of high LV mass with age-normalized RWTm > 0.41 or RWTp > 0.40. Further studies are required to establish prognostic implications of our findings.