Clinical Investigation
Roles for Echocardiography in Atrial Fibrillation
Left Atrial Mechanical Dispersion Assessed by Strain Echocardiography as an Independent Predictor of New-Onset Atrial Fibrillation: A Case-Control Study

https://doi.org/10.1016/j.echo.2019.06.002Get rights and content

Highlights

  • Left atrial (LA) mechanical dispersion is a useful predictor of atrial fibrillation.

  • This predictive value is superior and incremental to traditional predictors.

  • LA dispersion may detect the early LA remodeling regardless of LA enlargement.

Background

Left atrial (LA) enlargement is associated with atrial fibrillation (AF), but new-onset AF often occurs in the absence of LA enlargement. AF may be related to myocardial fibrosis, and even though left ventricular fibrosis is associated with mechanical dispersion, this phenomenon is not well studied in AF. We hypothesized that detection of LA dysfunction and mechanical dispersion using strain echocardiography is useful for predicting new-onset AF.

Methods

Baseline echocardiography was performed at entry in 576 community-based participants at risk of heart failure or AF. In this case-control study, we compared 35 individuals with new-onset AF (age 70 ± 4 years; 57% men) over 2 years of follow-up with 35 age- and sex-matched individuals who did not develop AF from the same cohort. Using speckle-tracking echocardiography, we measured the LA strain in each of 12 segments in the two- and four-chamber views. LA mechanical dispersion was defined as the SD of time to peak positive strain corrected by the R-R interval (SD-TPS, %).

Results

There was no significant difference in LA volume index (32.5 ± 9.2 mL/m2 vs 29.5 ± 8.3 mL/m2; P = .16); patients with new-onset AF had significantly worse LA pump strain (16.6% ± 4.3% vs 20.6% ± 4.3%; P < .01) and reservoir strain (31.4% ± 7.7% vs 38.0% ± 7.3%; P < .01) than those without AF. SD-TPS was significantly higher in patients with AF than in those without it (6.3% ± 2.3% vs 3.9% ± 1.6%; P < .01). SD-TPS was independently associated with new-onset AF after adjustment for patient characteristics, LA volume, and strain (hazard ratio = 1.26; 95% CI, 1.10-1.45; P < .01). In the nested Cox models, the model based on the LA volume and strain for predicting new onset AF was significantly improved by adding SD-TPS (P < .01).

Conclusions

LA dispersion obtained from strain echocardiography seems to provide incremental information about LA volume and function in the prediction of new-onset AF and warrants testing in a larger study.

Section snippets

Study Population

This case-control study was derived from a prospective, observational cohort study, which had the primary objective of early detection of heart failure (HF) and AF. This community-based cohort included asymptomatic individuals older than 65 years with more than one risk factor including hypertension (systolic blood pressure >140 mm Hg or preexisting use of antihypertensive medications), type 2 diabetes mellitus (based on self-reports of diagnosis or the current use of diabetic medications),

Patient Characteristics

Among 576 patients, new-onset AF developed in 35 participants (mean age, 70 ± 4 years; 57% men, 49% paroxysmal AF, and 51% nonparoxysmal AF) over 2 years of follow-up, and we age and sex matched 35 individuals who did not develop AF from the same cohort to act as controls. Thus, we performed our final analyses with data from a total of 70 participants (Table 1). Most patients had type 2 diabetes mellitus (54%), obesity (44%), hypercholesterolemia (48%), and hypertension (76%), but the average

Discussion

The principal finding of this study was that LA mechanical dispersion assessed by speckle-tracking echocardiography is a useful predictor of new-onset AF, superior and incremental to and independent of clinical risk factors and conventional echocardiographic predictors including LA enlargement and dysfunction.

Conclusion

LA dispersion assessed by speckle-tracking echocardiography is a predictor of new-onset AF, superior and incremental to and independent of clinical risk factors and conventional echocardiographic predictors including LA enlargement and dysfunction.

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  • Cited by (0)

    This work was partially supported by a Partnership grant (1149692) from the National Health and Medical Research Council, Canberra, the Tasmanian Community Fund, Hobart, and the Baker Heart and Diabetes Institute.

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