Automatic detection of atrial fibrillation using the coefficient of variation and density histograms of RR and ΔRR intervals

The paper describes a method for the automatic detection of atrial fibrillation, an abnormal heart rhythm, based on the sequence of intervals between heartbeats. The RR interval is the interbeat interval, and ΔRR is the difference between two successive RR intervals. Standard density histograms of the RR and ΔRR intervals were prepared as templates for atrial fibrillation detection. As the coefficients of variation of the RR and ΔRR intervals were approximately constant during atrial fibrillation, the coefficients of variation in the test data could be compared with the standard coefficients of variation (CV test). Further, the similarities between the density histograms of the test data and the standard density histograms were estimated using the Kolmogorov-Smirnov test. The CV test based on the RR intervals showed a sensitivity of 86.6% and a specificity of 84.3%. The CV test based on the ΔRR intervals showed that the sensitivity and the specificity are both approximately 84%. The Kolmogorov-Smirnov test based on the RR intervals did not improve on the result of the CV test. In contrast, the Kolmogorov-Smirnov test based on the ΔRR intervals showed a sensitivity of 94.4% and a specificity of 97.2%.