Patent ID: 7596405

Claim:
A method of detecting atrial fibrillation, the method comprising receiving an electrical signal representative of a beating heart; measuring atrial activity over a time window of three or more beats; measuring beat interval variation over the time window; combining the measures of atrial activity and beat interval variation to produce an indication of an atrial fibrillation condition in the electrical signal; and producing the indication with a processing system; wherein measuring atrial activity comprises measuring P waves and measuring beat interval variation comprises determining RR interval variation and combining comprises producing a combined measure C[i] determined by: C ⁡ [ i ] = { ⁢ R ⁡ [ i ] + p ⁡ ( P ⁡ [ i ] - 0.5 ) ⁢ ⁢ if ⁢ ⁢ Q ⁡ [ i ] ⁢ ⁢ and ⁢ ⁢ P ⁡ [ i ] > r ⁢ R ⁡ [ i ] ⁢ otherwise where Q[i] is a determined Boolean quality indicator; R[i] is the RR variability measure for the i th beat interval and P[i] is the P wave measure for the i th beat interval and wherein p is a P-wave multiplier and r is a P-wave minimum threshold value.