Single-beat determination of global longitudinal speckle strain in patients with atrial fibrillation.
BACKGROUND
Although global left ventricular (LV) systolic function is an important determinant of outcome, the assessment of global longitudinal speckle strain (GLS) in patients with atrial fibrillation (AF) is unreliable because of beat-to-beat variation. Previous studies have confirmed that LV contractility of each irregular beat is predicted from the ratio of preceding R-R (RR1) to pre-preceding R-R (RR2) intervals, and the value when the intervals are equal (RR1/RR2 = 1) estimates the average value of LV contractility. The aim of this study was to assess the clinical feasibility of an index that is obtained on the basis of the RR1/RR2 ratio for the estimation of GLS in patients with AF.


METHODS
We evaluated the RR1/RR2 ratio for the measurement of GLS with apical 4-chamber views in 20 patients with AF. We obtained the GLS for ≥13 cardiac cycles, and the relationship between each GLS at a given cardiac beat and the RR1/RR2 ratio was evaluated by linear regression analysis. The value of GLS at RR1/RR2 = 1 was compared with the measured average value.


RESULTS
The GLS showed a significant correlation with the RR1/RR2 ratio (r = -0.80). The calculated value of GLS at RR1/RR2 = 1 was quite similar to the average value (-10.17 ± 2.1 % vs. -10.06 ± 2.1 %). The GLS of a single beat with identical RR1 and RR2 intervals showed a significant correlation compared with the measured average value over all cardiac cycles (r = 0.94, y = 0.90x - 0.97).


CONCLUSIONS
The GLS at RR1/RR2 = 1 allows the LV systolic parameter to be accurately evaluated during AF and obviates the less reliable process of averaging multiple irregular beats.
Division of Cardiology, Shimane University Faculty of Medicine, 89-1 Enya-cyo, Izumo, 693-8501, Japan.
Kazuto
K
Yamaguchi
Division of Cardiology, Shimane University Faculty of Medicine, 89-1 Enya-cyo, Izumo, 693-8501, Japan.
Hiroyuki
H
Yoshitomi
Division of Cardiology, Shimane University Faculty of Medicine, 89-1 Enya-cyo, Izumo, 693-8501, Japan.
Saki
S
Ito
Division of Cardiology, Shimane University Faculty of Medicine, 89-1 Enya-cyo, Izumo, 693-8501, Japan.
Tomoko
T
Adachi
Division of Cardiology, Shimane University Faculty of Medicine, 89-1 Enya-cyo, Izumo, 693-8501, Japan.
Nobuyuki
N
Takahashi
Division of Cardiology, Shimane University Faculty of Medicine, 89-1 Enya-cyo, Izumo, 693-8501, Japan. kaz@med.shimane-u.ac.jp.
Kazuaki
K
Tanabe
Atrial fibrillation; Echocardiography; Left ventricular function; Strain