Abstract 18082: Left Atrial Strain in Normal Individuals is Influenced by Age and Left Atrial Volume: Implications for Evaluation of Atrial Function in Hypertensive Patients with Diastolic Dysfunction.
Background: LA size is a potent predictor of cardiovascular risk. Less is known about the prognostic value of LA function, however. We have shown that left atrial (LA) strain (εLA), a descriptor of LA reservoir function, is reduced in hypertensives (HTN). However, εLA , might deteriorate with age and decrease at higher LA volumes. Our goal was to derive a model for εLA which took age and LA size into account, so as to more precisely diagnose LA dysfunction.
Methods: 100 healthy volunteers (NLS; 50±15yrs; 58 women) underwent standard echocardiography with evaluation of diastolic function, LA volume (area-length) and εLA by speckle tracking (STI) (GE). Multivariate models were derived from NLS to generate regression equations that were tested in 50 HTN with grade 1–2 diastolic dysfunction (76±14yrs; 72%females) without significant valvular disease.
Results: Reduced LA function was defined as εLA <24.4% (5th percentile in normals). In stepwise multiple regression, as hypothesized, εLA was significantly and inversely associated with age (β=−0.29: p<0.01) and LA volume (β=−0.25: p0.80). The following regression equation was derived to correct εLA (εLA -c): εLA_c=εLA+0.198x(age-50)+0.155×(LAvol)-4, where LAvol is unadjusted LA volume in mL. We then repeated the analysis using this ‘corrected’ εLA-c, with a partition value of <29.4% (5th percentile). Prevalence of reduced LA function was significantly higher in HTN as compared to NLS by both classifications (p<0.01). However as compared to classification by unadjusted εLA, prevalence of LA dysfunction was significantly lower by εLA-c (16% vs 47%; p<0.001).
Conclusions: Atrial function by εLA decreases physiologically with ageing and increasing LA size. These associations should be taken into account when evaluating LA reservoir function. We speculate that εLA-c might conceivably refine cardiovascular risk prediction of LA size.
Graph: Prevalence of reduced atrial function by unadjusted and adjusted LA strain.
- © 2010 by American Heart Association, Inc.