The fractal dimension of atrial fibrillation: a new method to predict left atrial dimension from the surface electrocardiogram.
BACKGROUND
Previous studies have shown inconsistent relationships between left atrial size and various characteristics of atrial fibrillation seen on the surface electrocardiogram. The purpose of this study was to determine if the fractal dimension of atrial fibrillation derived from the ECG would be useful in predicting left atrial size.


METHODS
The fractal dimension (D) was calculated using resting 12-lead ECGs from 53 patients (age 48-90) in chronic atrial fibrillation (greater than one year duration). D is the slope of the log/log plot of total length of a strip of atrial fibrillation against progressively decreasing lengths of measurement, plus one. Left atrial size was determined by standard M-mode echocardiography.


RESULTS
When D was large (greater than 1.14), all patients had a left atrial size of 4.6 cm or greater. When D was small (less than 1. 09), all patients had a left atrial size of 4.6 cm or smaller. Values of D between 1.09 and 1.14 showed no relationship to atrial size. Larger values of D were associated with a higher degree of irregularity, roughness, and complexity in the surface ECG rhythm strips.


CONCLUSIONS
In patients with chronic atrial fibrillation, the fractal dimension D derived from the surface ECG may be useful in predicting left atrial size.
Peters
R M
RM
Division of Cardiology, North Shore University-Long Island Jewish Health Care System, Manhasset, NY, USA.
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000150:complications / Q000473:pathology*; D004562:Electrocardiography; D005260:Female; D017709:Fractals; D006325:Heart Atria / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged