The clinical utility of normal findings on noninvasive cardiac assessment in the prediction of atrial fibrillation.
BACKGROUND
The absence of abnormalities on noninvasive cardiac assessment possibly confers a reduced risk of atrial fibrillation (AF) despite the presence of traditional risk factors.


HYPOTHESIS
Normal findings on noninvasive cardiac assessment are associated with a lower risk of AF development.


METHODS
We examined the clinical utility of normal findings on routine noninvasive cardiac assessment in 5331 participants (85% white; 57% women) from the Cardiovascular Health Study who were free of baseline AF. The combination of a normal electrocardiogram (ECG) + normal echocardiogram was assessed for the development of AF events. A normal ECG was defined as the absence of major or minor Minnesota code abnormalities. A normal echocardiogram was defined as the absence of contractile dysfunction, wall motion abnormalities, or abnormal left ventricular mass. Cox regression was used to compute the 10-year risk of developing AF.


RESULTS
During the 10-year study period, a total of 951 (18%) AF events were detected. A normal ECG (multivariable hazard ratio [HR]: 0.80, 95% confidence interval [CI]: 0.69-0.92) and normal echocardiogram (multivariable HR: 0.75, 95% CI: 0.65-0.87) were associated with a reduced risk of AF in isolation. This association improved in those with normal ECG + normal echocardiogram (multivariable HR: 0.66, 95% CI: 0.55-0.79) compared with participants who had abnormal ECG + abnormal echocardiogram (referent).


CONCLUSIONS
Normal findings on routine noninvasive cardiac assessment identify persons in whom the risk of AF is low. Further studies are needed to explore the utility of this profile regarding the decision to implement certain risk factor modification strategies in older adults to reduce AF burden.