February 1, 2008Clinical CardiologyOpen Access

Assessment of Atrial Electromechanical Coupling and Influential Factors in Nonrheumatic Paroxysmal Atrial Fibrillation

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Structured PICO

Population

100 patients with nonrheumatic paroxysmal atrial fibrillation (PAF) (mean age 56.49, 67% male) and 87 sex-matched normal controls (mean age 42.38, 67% male) in China. Exclusions: persistent or permanent AF, valvular heart disease, hyperthyroidism, acute myocardial infarction, or cardiac surgery.

Comparator

87 sex-matched normal controls

Outcome

Atrial electromechanical coupling intervals (P-A1, P-A2, P-A3) and their dispersion (T1, T2, T3) measured by Doppler tissue imagingsurrogate

Patients with paroxysmal atrial fibrillation exhibit prolonged atrial electromechanical coupling and greater dispersion, which correlates with left atrial enlargement, aging, and duration of PAF episodes.

Limitations

An error in angulation between the transducer beam and the left and right atrioventricular annulus could affect the magnitude of the tissue velocity
Left atrial upper-inferior, RA-LR and atrial volume may be helpful in determining the change of the atrial chamber shape but were not fully utilized

Implication

Prolonged atrial electromechanical coupling in PAF supports further study; hypothesis-generating and should not yet change practice.

Abstract

BACKGROUND: Sequential analysis of atrial electromechanical coupling (P-A) by Doppler tissue imaging (DTI) might provide important insight into the mechanisms of paroxysmal atrial fibrillation (PAF). HYPOTHESIS: The purpose of this study was to evaluate P-A and the dispersion of P-A, and to analyze the influential factors of P-A. METHODS: One hundred and ten patients with PAF and 87 normal controls were enrolled. Using DTI, the time intervals from the beginning of P-wave to the onset of atrioventricular ring motion related to atrial contraction were measured. RESULTS: Atrial electromechanical coupling at the interventricular septum atrioventricular annulus (P-A1), left lateral mitral annulus (P-A2) and right lateral tricuspid annulus (P-A3) in PAF group were significantly longer than those in control (p < 0.001). The difference between P-A2 and P-A1 (T1), P-A2 and P-A3 (T3) in PAF group were greater than those in control before age correction (p < 0.05). The linear regression analysis showed that the duration of PAF episodes and age were the greatest influential factors of P-A1 (r = 0.564). Left atrial anterior-posterior dimension (LAD) and age were the greatest influential factors of P-A2 (r = 0.459). The LAD was the greatest influential factors of T1 and T3 (r = 0.408, 0.542). CONCLUSIONS: The atrial electromechanical coupling was significantly longer and the dispersion of P-A at left lateral mitral annulus was greater in PAF patients. The prolongation of P-A may be related to left atrial enlargement, long episodes of PAF and aging and the dispersion of P-A at left lateral mitral annulus to LAD.