Left atrial systolic function assessed by left atrial ejection force in patients with sick sinus syndrome and paroxysmal atrial fibrillation

We evaluated left atrial systolic function using left atrial ejection force (LAEF) in 19 patients with sick sinus syndrome (SSS) and in 20 with paroxy smal atrial fibrillation (Paf) whose ages ranged from 48 to 80 years. We al so evaluated 35 normal individuals for comparison. The LAEF was calculated as 1 / 3 x mitral valve area x (peak velocity of A wave)(2) using two-dimen sional and pulsed-Doppler echocardiography according to Newton's law of mot ion and hydrodynamics. In normal individuals, LAEF positively correlated wi th age (r = 0.82, p < 0.01). Normal LAEF was calculated as 0.098 x age - 0. 74 (kdynes) from the regression line. Because of this correlation, we used age-corrected LAEF (%LAEF) that was calculated as (measured LAEF/normal LAE F) x 100. The results showed that this value was 53 +/- 26% in patients wit h SSS and 54 +/- 26% in patients with Paf. Both were significantly lower th an normal individuals (p < 0.001). Among SSS subtypes, %LAEF was lower in t ypes II and III than in type I (51 +/- 14%, 37 +/- 19%, and 81 +/- 35%, res pectively). In conclusion, left atrial systolic function is depressed in pa tients with Paf and SSS, in particular, types II and III. These results sug gest that the pathological abnormalities extend not only to the sinus node but also to the left atrial muscle in patients with SSS and Paf.