New Echo Method Triages Afib Stroke Risk

This one I'll leave to the doctors to decipher but you could impress your doctor by asking about it.
http://www.medpagetoday.com/clinical-context/Strokes/26189
Among patients with atrial fibrillation, a relatively new technique called speckle tracking echocardiography may help predict who is at risk for stroke, researchers reported.
The technique allows calculation of the global left atrial strain -- a measure of how much the dimension of the region changes over time, according to Partho Sengupta, MD, of the University of California Irvine in Irvine, Calif., and colleagues.
In a small cohort study, the global left atrial strain was significantly reduced in patients with atrial fibrillation, Sengupta and colleagues reported in the May issue of the Journal of the American Society of Echocardiography.
As well, it was the only echocardiographic variable associated with an increased risk of thromboembolism, as measured by the CHADS₂ scale, the researchers reported.
"To our knowledge, this is the first study that substantiates the relationship between (left atrial) strain and the clinical risk for stroke as quantified with CHADS₂ score," the researchers wrote.
Indeed, the study "throws new light on this relatively new measure of (left atrial) function," argued Christopher Choong, MBBChir, PhD, of the Royal North Shore Hospital in Sydney, Australia, in an accompanying editorial.
The results suggest that left atrial strain has the potential to be "one of the long-awaited missing links in stroke risk prediction using transthoracic echocardiography," Choong said.
But because the study is small, he added, it remains "premature to draw firm conclusions at this time about prognostic value and stroke risk prediction."
Indeed, the overall study included only 36 subjects with atrial fibrillation and 41 control participants and a substudy, evaluating the prognostic value of the strain measurement, included only 26, the researchers reported.
Sengupta and colleagues found that all conventional echocardiographic parameters except left ventricular diameter and filling pressure were significantly different (at P<0.001 for all comparisons) between patients and controls.
Indexed left atrial volume was significantly higher in subjects with atrial fibrillation than in controls, and the emptying fraction was reduced (at P<0.001 for both).
Using the speckle tracking method, the researchers were able to assess regional strain in 97% of left atrial segments, they reported.
They found that global longitudinal left atrial strain was significantly reduced (at P<0.001) in patients compared with controls, at 17.7 versus 35.5.
In a multivariate regression analysis, they reported, only indexed left atrial volume and atrioventricular plane displacement were independent predictors of global left atrial longitudinal strain, at P=0.004 and P<0.001, respectively.
In a logistic regression analysis, global left atrial strain was the only echocardiographic variable associated with greater odds of having a CHADS₂ score of at least 2. The odds ratio was 0.86, with a 95% confidence interval from 0.76 to 0.9, which was significant at P=0.02.
The researchers followed 26 of the fibrillation patients for a median period of 394 days, during which nine required inpatient care and three died.
Among those patients, they found, the CHADS₂ score was not significantly associated with the risk of admission or death but a second model, adding indexed left atrial volume, increased the predictive value significantly (at P<0.001).
A third model including both volume and global strain was significantly better than the second model at P=0.003, Sengupta and colleagues reported.
They cautioned that the study is small and needs confirmation in larger, prospective analyses.