Left atrial strain measured by three-dimensional echocardiography predicts atrial fibrillation in the general population.

BACKGROUND: Left atrial (LA) strain by three-dimensional echocardiography (3DE), has been proposed as a more accurate measure of LA function, providing incremental prognostic benefits over traditional two-dimensional approaches. OBJECTIVES: Our aim was to evaluate the prognostic value of LA strain by 3DE in predicting incident atrial fibrillation (AF) in the general population. METHODS: The study included 4466 participants from a prospective longitudinal cohort study in the general population, among these 3DE LA strain was analysed in 1935 participants. The endpoint was incident AF. Adjustments were made for the CHARGE-AF clinical risk score. RESULTS: Mean age was 54 ± 17 years, 43 % were male. During a median follow-up time of 4.8 years (interquartile range 4.3-5.5 years) 59 participants (3.0 %) developed AF. In univariable analysis, all three parameters were associated with incident AF (p value for all <0.01). After multivariable adjustments, only LA reservoir strain (LASr) and LA contractile strain (LASct) were associated with incident AF (LASr: HR 1.12 (1.07-1.17), p < 0.001, per 1 % decrease; LASct: HR 1.16 (1.09-1.24), p < 0.001, per 1 % decrease), whereas LA conduit strain (LAScd) was not (HR 1.04 (0.98-1.10), p = 0.17, per 1 % decrease). Both LASr (continuous net reclassification index 0.37 ± 0.14; p = 0.003) and LASct (continuous net reclassification index 0.41 ± 0.14; p = 0.002) provided incremental prognostic information beyond the CHARGE-AF risk score. CONCLUSION: LASr and LASct measured by 3DE are independently associated with incident AF and provided incremental prognostic information beyond existing risk scores.

Normal values for left atrial strain, volume, and function derived from 3D echocardiography: the Copenhagen City Heart Study.

AIMS: 3D echocardiographic (3DE) assessment of the left atrium (LA) is a new modality of potential clinical value. Age- and sex-based normative values are needed to benchmark these parameters for clinical use. METHODS AND RESULTS: Of 4466 participants in the 5th Copenhagen City Heart Study, a prospective longitudinal cohort study on the general population, 2082 participants underwent 3DE of the LA. Healthy participants were included to establish normative values for LA strain, volume, and function by 3DE. The effects of age and sex were also evaluated. After excluding participants with comorbidities, 979 healthy participants (median age 44 years, 39.6% males) remained. The median and limits of normality (2.5th and 97.5th percentiles) for functional and volumetric measures were as follows: LA reservoir strain (LASr) 30.8% (18.4-44.2%), LA conduit strain (LAScd) 19.1% (6.8-32.0%), LA contractile strain 11.7% (4.3-22.2%), total LA emptying fraction (LAEF) 61.4% (47.8-71.0%), passive LAEF 37.7% (17.4-53.9%), active LAEF 37.4% (22.2-52.5%), LA minimum volume index (LAVimin) 10.2 (5.9-18.5) mL/m2, and LA maximum volume index (LAVimax) 26.8 (16.5-40.1) mL/m2. All parameters changed significantly with increasing age (P value for all <0.001). Significant sex-specific differences were observed for all parameters except active LAEF and LAVimax. Sex significantly modified the association between age and LASr (P for interaction < 0.001), LAScd (P for interaction < 0.001), LAVimin (P for interaction = 0.037), and total LAEF (P for interaction = 0.034) such that these parameters deteriorated faster with age in females than males. CONCLUSION: We present age- and sex-specific reference material including limits of normality for LA strain, volume, and function by 3DE.

Even Mild Mitral Regurgitation is Associated with Incident Atrial Fibrillation in the General Population.

BACKGROUND: Mitral regurgitation (MR) can be difficult to quantify. We sought to investigate whether the MR jet area to left atrial (LA) area ratio (MR/LA-ratio) method for quantifying MRs can be used to predict incident AF in the general population. METHODS: The study included 4,466 participants from the 5th Copenhagen City Heart Study, a prospective general population study, who underwent transthoracic echocardiography. MR jet area was measured and indexed to LA area. The endpoint was incident AF. RESULTS: MR was quantified in 4,042 participants (mean age: 57 years, 43% men). Of these, 198 (4.9%) developed AF during a median follow-up period of 5.3 years (IQR: 4.4-6.1 years). MR was present in 1,938 participants (48%) including 1593 (39%) trace/mild MRs (MR/LA-ratio ≤ 20% and ≤4 cm2). In unadjusted analysis, MR/LA-ratio was associated with incident AF (HR: 1.06 (1.00-1.13), p = 0.042 per 5% increase) but not after adjusting for CHARGE-AF score. However, the association was modified by age (p for interaction = 0.034), such that MR/LA-ratio was associated with AF only in participants ≤73 years. In these participants, MR/LA-ratio was independently associated with AF after adjusting for CHARGE-AF score (HR: 1.14 (1.06-1.24), p = 0.001, per 5% increase). This finding persisted when restricting the analysis to participants without moderate or severe MR and normal LA size (HR: 1.35 (1.09-1.68), p = 0.005, per 5% increase). CONCLUSION: Mitral regurgitation, including even trace regurgitations quantified by MR/LA-ratio is independently associated with incident AF in individuals ≤73 years of age.