Patent ID: 8038675

Claim:
An apparatus, comprising: means for endocardial spectral mapping of endocardial signals from at least one atrial wall point having high-density autonomic innervation configured to operate during sinus rhythm, means for obtaining an endocardial signal from a volume of myocardium of the at least one atrial wall point, the endocardial signal having a fractionated spectrum in the frequency domain of a Fourier transform of the endocardial signal, means for ablating at least a portion of the myocardium of the at least one atrial wall point, wherein the ablation reduces or eliminates the frequency domain signal above about 300 Hz, and wherein the means for endocardial spectral mapping comprises a software program for performing a Fourier transformation of myocardial signals to identify at least one of a compact myocardial substrate and a fibrillar myocardial substrate.