US 2007/0179393 A1Published application

Method and apparatus for synthetically detecting ventricular fibrillation

AssigneeShenzhen Mindray Bio-Medical Electronics Co., Ltd.

InventorsWenyu Ye, Junbiao Hong, Shufeng Li, San Lu

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Abstract

The present application discloses a complexity-based method for synthetically detecting ventricular fibrillation, which centers on complexity calculations while incorporating a plurality of feature values and thus differentiates more effectively among various types of ECG signals. The method further modifies the complexity algorithm, making it more adapted to reflecting characteristics of the VF-related signals, thereby enabling high sensitivity and specificity of detection. Further, the related calculation load is reduced according to the algorithm. As such, the method can fully satisfy the clinical needs and is aimed for solving the problems of low sensitivity, low specificity and weak anti-interference ability present in current medical equipment for detecting ventricular fibrillation, such as monitors, implanted cardioversion defibrillator (ICD), automatic external defibrillator (AED) and so on. Systems for performing the method are also disclosed.

Claims15

Dependent claims

A complexity-based detection method for synthetically detecting ventricular fibrillation (VF), comprising steps of:

(1) collecting a n number data samples from a ECG signal at a predetermined sampling rate;
(2) preprocessing said data sample by means of noise filtering to produce data y(n);
(3) performing amplitude standardization to amplitude value A of data y(n), thereby obtaining data y1(n);
(4) calculating a slope peak value SLMax, a probability density value PD and a complexity value C(n) of the data y1(n) respectively;
(5) setting respective threshold values:
a complexity high threshold CHigh, a complexity low threshold CLow, a complexity medium threshold CMid, a first amplitude probability density threshold PDJ1, a second amplitude probability density threshold PDJ2, a first slope threshold SLMaxJ1 and a second slope threshold SLMaxJ2, wherein PDJ1<PDJ2, SLMaxJ1>SLMaxJ2;
(6) determining VF based on the following condition, wherein IsVF refers to a previous indication of VF and initialized to False for the first determination:
if C(n)>Cmid && PD<PDJ1 && SLMax<SLMaxJ1 && IsVF=False ∥ C(n)>Chigh && PD<PDJ2 && SLMax<SLMaxJ2 && IsVF=False ∥ C(n)>Clow && IsVF=True, determining that VF occurs and setting IsVF=True;
otherwise, IsVF=False, the resulted IsVF value is then stored for next usage;
(7):
re-sampling m samples to substitute for the first m samples among the n data samples so as to form a n number of new data samples, then proceeding with steps (2) to (4) and (6).

8 more elements

A VF detector, comprising:

a data sampler for sampling a n number of samples of an ECG signal at a predetermined sampling rate;
a filter for preprocessing the samples so as to obtain data y(n);
a standardizer for performing amplitude standardization to the data y(n) so as to obtain data y1(n);
a numeric value calculator, for calculating parameters including a slope peak value SLMax, a probability density value PD, and a complexity value C(n) of the data y1(n);
an arbitrator for detecting a VF in accordance with the calculated slope peak value SLMax, probability density value PD and complexity value C(n) respectively.

2 more elements

Dependencies are inferred from the claim text.