Frequent premature atrial contractions impair left atrial contractile function and promote adverse left atrial remodeling.

OBJECTIVES: This study assessed if frequent premature atrial contractions (PACs) were associated with decreased left atrial (LA) strain and adverse remodeling.
BACKGROUND: Left atrial dysfunction and enlargement increases risk of stroke. If frequent PACs cause LA dysfunction and remodeling, PAC suppressive therapy may be beneficial.
METHODS: Inclusion criteria were age ≥18 years and sinus rhythm. Exclusion criteria were atrial fibrillation or any etiology for LA enlargement. Hundred and thirty-two patients with frequent PACs (≥100/24 hours) by Holter were matched to controls. Speckle tracking strain of the left atrium was performed from the 4-chamber view. Strain measurements were LA peak contractile, reservoir and conduit strain and strain rates.
RESULTS: In the frequent PAC vs control group, PACs were more frequent (1959 ± 3796 vs 28 ± 25/24 hours, P < .0001). LA peak contractile strain was reduced in the group with frequent PACs vs controls (-7.85 ± 4.12% vs -9.33 ± 4.45%, P = .006). LA peak late negative contractile strain rate was less negative in the frequent PAC vs control group (-0.63 ± 0.27 s-1 vs -0.69 ± 0.32 s-1 , P = .051). LA reservoir and conduit strain and strain rates did not differ. LA volume index (LAVI) was larger in the frequent PAC vs control group (26.6 ± 7.8 vs 24.6 ± 8.8 mL/m2 , P < .05). Frequent PACs were an independent predictor of reduced LA peak contractile strain and reduced LA peak late negative contractile strain rate.
CONCLUSIONS: Patients with frequent PACs have reduced LA peak contractile strain and strain rates and larger LAVI compared to controls. Frequent PACs are an independent predictor of reduced LA peak contractile strain and strain rate. These findings support the hypothesis that frequent PACs impair LA contractile function and promote adverse LA remodeling.