Abstract 4240: Quantitative Assessment of Left Atrial Function in Patients with Hypertension and Impaired Diastolic Function
Background: Longstanding hypertension is associated with abnormalities of ventricular diastolic function and may result in left atrial (LA) enlargement. Nevertheless, the prevalence of abnormalities of LA function and its relationship with ventricular diastolic function has not been well defined.
Methods: We studied 228 individuals enrolled in the EXCEED trial, designed to assess the effect of standard versus aggressive blood pressure lowering using a combination of valsartan and amlodipine, on diastolic and vascular functions. Patient enrolled were ≥ 45 years old with stage 2 hypertension (161±14/92±13 mmHg), had ejection fraction>50% and impaired diastolic performance defined by Tissue Doppler Imaging of early diastolic velocity of lateral mitral annulus (E′), without heart failure. LA longitudinal functions were assessed from echocardiograms using myocardial speckle tracking. LA peak expansion strain (SS), LA strain rate in both passive (SRe) & active emptying phases (SRa) were measured. Normal values of LA functions were defined from 51 age-matched controls.
Results: Both LA SS and SRe were related to E′ (7.6 ± 1.2 cm/s), after adjusting for age, heart rate and systolic blood pressure (r = 0.41, p <0.001 for SS; r=−0.61, p <0.001 for SRe, Table⇓). Moreover, adjusted SS and SRe were weakly related to E/E′, which is a surrogate of filling pressure (r=−0.2, p<0.05 for SS; r=0.2, p<0.05 for SRe). Neither SRa nor volume index of LA were related to parameters of diastolic function. LA SS and SRe were significantly lower in study group compared to controls (35.8 ± 7.2 % vs. 40.8 ± 6.2%, p <0.001 for SS; −0.98±0.24 s−1 vs. −1.7±0.46 s−1, p<0.001 for SRe).
Conclusion: LA function, assessed by strain and strain rate imaging is related to measures of ventricular diastolic function in hypertensive population without heart failure. LA functional changes may be more sensitive than structural changes to early abnormalities of left ventricular diastolic function in this population.