Introduction:
Limited data are reported about age related changes of LA and RA functions, and interatrial relationship.
Methods:
131 normal subjects (19-78 yrs, 89 women), divided in 4 age groups, were studied by conventional and speckle tracking echo (STE). LA and RA volumes were measured: pre atrial contraction (Vp), minimal (Vmin), and maximal (Vmax), and computed to define atrial ejection fractions: active EF = (Vp-Vmin)/Vp; expansion index EI = (Vmax-Vmin)/Vmin; passive EF = (Vmax-Vp)/Vmax. Active function was assessed from negative strain at atrial contraction (GSA-) and time from P onset to peak (TGSA-), and late diastolic strain rate (GSRL); passive function from positive global strain (GSA+) and time from R to peak (TGSA+), and from early negative diastolic SR (GSRE); reservoir function from the sum of GSA- and GSA+ (SUMGSA), positive global SR at the beginning of ventricular systole (GSR+) and derived time from P onset (TGSR+). We defined for LA a maximal difference (DIF) of all derived times, as a measurement of LA synchrony, and also a difference between RA times and maximal correspondent LA times, as an interatrial synchrony.
Results:
All LAEFs, Vmin, and Vp decreased over 50 yrs, and Vmax over 60 yrs. RA reservoir function decreased over 60 yrs, while passive RA function over 50 yrs. Active LA function (GSRL) decreased over 60 yrs. LA reservoir and conduit function decreased over 50 yrs. All derived times were increased over 40 yrs. LA and also interatrial contraction and relaxation synchrony were altered only after 60 yrs (all p<0.001) (Tables). Correspondent RA and LA functions are significantly correlated, irrespective of age (r=0.6, p<0.001).
Conclusion:
Although LA and RA functions are strongly correlated, they have different age related changes. RA volumes, EFs, and active function were not affected by age, whereas LAEFs, volumes, passive and reservoir LA and RA functions decreased over 50 yrs. LA and also interatrial synchrony were altered after 60 yrs.
Age-related changes in contraction and relaxation of rat diaphragm