Echocardiographic
diastolic function (DF) assessment remains a challenge in atrial fibrillation
(AF), because indexes such as E/A cannot be used and because chronic, rate
controlled AF causes chamber remodeling. To determine if echocardiography can
accurately characterize diastolic chamber properties we compared 15 chronic AF
subjects to 15, age matched normal sinus rhythm (NSR) subjects using simultaneous echocardiography-cardiac catheterization
(391 beats analyzed). Conventional DF parameters (DT, Epeak, AT, Edur,
E-VTI, E/E\') and validated, E-wave derived, kinematic modeling based chamber
stiffness parameter (k), were
compared. For validation, chamber stiffness (dP/dV) was independently determined from simultaneous, multi-beat
P-V loop data. Results show that neither AT, Epeak nor E-VTI
differentiated between groups. Although DT, Edur and E/E’ did
differentiate between groups (DTNSR vs. DTAF p < 0.001, EdurNSR vs. EdurAF p < 0.001, E/E\'NSR vs. E/E\'AF p < 0.05), the model derived chamber stiffness
parameter k was the only parameter
specific for chamber stiffness, (kNSR vs. kAF p < 0.005). The invasive gold
standard determined end-diastolic stiffness in NSR was indistinguishable from
end-diastolic (i.e. diastatic) stiffness in AF (p = 0.84). Importantly, the analysis provided mechanistic insight
by showing that diastatic stiffness in AF was significantly greater than
diastatic stiffness in NSR (p <
0.05). We conclude that passive (diastatic) chamber stiffness is increased in normal
LVEF chronic, rate controlled AF hearts relative to normal LVEF NSR controls
and that in addition to DT, the E-wave derived, chamber stiffness specific
index k, differentiates between AF
vs. NSR groups, even when invasively determined end-diastolic chamber stiffness
fails to do so.
Credits: Sina Mossahebi; Leonid Shmuylovich; Sándor J. Kovács