Enhanced rhythm identification in compression corrupted ECG

Apparatus for aiding in the analysis of ECG signals to indicate whether or not the ECG signals are from a heart that has QRS rhythms, comprising:

• computer circuit means that receives ECG signals that contain chest compression artifacts, that recognizes the chest compression artifacts, and that analyzes portions of the ECG signals that lie between the chest compression artifacts, said computer circuit means being constructed to detect QRS complexes by detecting large slopes in ECG signals along large amplitudes of voltage change;
• said computer circuit is constructed to detect slopes on the order of at least 30 millivolts per second between points that vary in amplitude by an amount that is at least about 10% of variations in amplitude caused by the compression artifacts.

Apparatus for aiding in the analysis of ECG signals to indicate whether or not the ECG signals are from a beating heart with perfusion rhythm, comprising:

• computer circuit means that receives ECG signals that contain chest compression artifacts and that recognizes the chest compression artifacts, said computer circuit means being constructed to detect QRS complexes by detecting large slopes in ECG signals along large amplitudes of voltage change;
• said chest compression artifacts are uniformly spaced in time, and said computer circuit means is constructed to confirm the presence of QRS complexes that indicate perfusion rhythm by the presence of detected QRS complexes between successive pairs of compression artifacts, where a phase shift between compression artifacts and QRS complexes changes regularly.

A method for determining a treatment of a victim of possible cardiac arrest, usually due to a heart attack, while chest compressions are applied to the victim and ECG (electrocardiogram) signals of the victim are monitored to determine whether or not a defibrillator shock should be applied to the victim, comprising:

• continuing to apply chest compressions to the victim while generating corrupted ECG signals that are corrupted by chest compression artifacts;
• analyzing the corrupted ECG signals that are corrupted by chest compression artifacts to determine whether or not a defibrillating shock should be applied to the victim;
• said step of analyzing the corrupted ECG signals includes producing first calculations representing an autocorrelation of an average of spike regions of a transform of the ECG signal and producing second calculations representing a crosscorrelation of said plurality of spike regions, and calculating an integral of a magnitude of differences between said crosscorrelation and said autocorrelations, and determining whether or not to deliver a defibrillating shock based on the amplitudes of said integrals.

Apparatus which analyzes ECG signals taken all from the same location on the body of a victim to indicate whether or not the ECG signals are from a heart with QRS rhythms, comprising:

• computer circuit means constructed to generate integral signals that represent a computation of a transform of said ECG signal, a computation of an autocorrelation of a group of spike regions of the transform, a computation of crosscorrelations of the spike regions of the group, and a computation of integrals of the differences between each crosscorrelation and said autocorrelation;
• said computer circuit means is constructed to indicate that the ECG signals are from a beating heart with perfusion rhythm when said integral signals are less than a predetermined value.