Figure 1

Flow diagram for pattern recognition in atrial fibrillation signals. $\mathrm{ip}=\text{inner product}$, $\mathrm{\Sigma }=\text{summation}$, $-=\text{difference}$, $p=\text{pattern}$, $S=\text{signature}$, ℓ= number of candidate patterns selected by the Euclidean distance threshold value. The number of initial CFAE recordings $m=216$. After addition of interference, the total number of recordings $m-2$ is 214. After comparison of the 214 spectral signatures with the power spectrum of the mean signal, based on a first threshold level Th1 for Euclidean distance ED1, ℓ candidate patterns are selected. By comparing the spectral signatures of the ℓ candidate signals using a second threshold level Th2 for Euclidean distance ED2, selections are made as to whether each candidate contains pattern A, pattern B, or no pattern.