Provided is an atrial fibrillation detection system which can reduce the burden on a test subject, with which it is possible to detect even paroxysmal atrial fibrillation, and which can be used in the home, contributing to early detection of atrial fibrillation. This atrial fibrillation detection system detects the presence of atrial fibrillation in a subject, and is provided with a heartbeat period measurement means that measures heartbeat periods of the heart; a normalized heartbeat period computation means that computes normalized heartbeat periods DR(N) from heartbeat periods of the heart measured by the heartbeat period measurement means; an abnormal normalized heartbeat period cumulation means that, from among a prescribed number of successive normalized heartbeat periods DR(N), adds up the count of abnormal normalized heartbeat periods that have an absolute value exceeding a normal heartbeat period value; and a comparison/determination means that compares the cumulative count of the abnormal normalized heartbeat periods and a normal cumulative count threshold value, and in the event that the cumulative count of the abnormal normalized heartbeat periods exceeds the normal cumulative count threshold value, determines that atrial fibrillation has occurred.

This disclosure relates generally to biomedical signal processing, and more particularly to method and system for physiological parameter derivation from pulsating signals with reduced error. In this method, pulsating signals are extracted, spurious perturbations in the extracted pulsating signals are removed for smoothening, local minima points in the smoothened pulsating signal are derived, systolic maxima point between two derived local minima are derived, most probable pulse duration and most probable peak-to-peak distance are derived, dicrotic minima is removed while ensuring that every dicrotic minima is preceded by a systolic maxima point and followed by a beat start point of said systolic maxima, diastolic peak is derived while ensuring that every dicrotic maxima is preceded by a diastolic notch followed by next beat start point of that maxima, and physiological parameters are derived from the derived local minima points, systolic maxima points, dicrotic notch and diastolic peak.

There is a method and system for detecting heartbeat irregularities comprising the steps of receiving a dataset representative of at least one waveform, the at least one waveform indicative of a subject's heart activity over a predetermined period of time; identifying from the data representative of at least one waveform, a plurality of peaks, each peak corresponding to a heartbeat; identifying from the predetermined period of time the time occurrence of each peak; calculating the difference (duration) between the time occurrence of each peak with its adjacent peak; determining the difference between each duration; classifying the absolute value of the difference into one of at least three intermediate categories; wherein each intermediate category comprises a specified range such that the absolute value is categorized into the intermediate category if it falls between the range; the intermediate categories further providing an indication of whether the subject has heartbeat irregularity.

A system to measure intracardiac impedance includes implantable electrodes and a medical device. The electrodes sense electrical signals of a heart of a subject. The medical device includes a cardiac signal sensing circuit coupled to the implantable electrodes, an impedance measurement circuit coupled to the same or different implantable electrodes, and a controller circuit coupled to the cardiac signal sensing circuit and the impedance measurement circuit. The cardiac signal sensing circuit provides a sensed cardiac signal. The impedance measurement circuit senses intracardiac impedance between the electrodes to obtain an intracardiac impedance signal. The controller circuit determines cardiac cycles of the subject using the sensed cardiac signal, and detects tachyarrhythmia using cardiac-cycle to cardiac-cycle changes in a plurality of intracardiac impedance parameters obtained from the intracardiac impedance signal.

Medical devices and methods for making and using medical devices are disclosed. An example method may include a method of identifying an activation time in a cardiac electrical signal. The method may include sensing a cardiac electrical signal, generating an approximation signal based at least in part on one or more parameters of the cardiac electrical signal, identifying a fiducial point on the approximation signal and determining, based at least in part on a timing of the fiducial point in the approximation signal, an activation time in the cardiac electrical signal.

A system for monitoring a subject for an arrhythmia includes an external monitoring device (EMD) configured to be disposed outside of a subject's body. The EMD includes a first communication component configured to receive, from a medical device, a first physiological parameter signal and an indication of a detected trigger event associated with a first portion of the first physiological parameter signal. The trigger event is indicative of a potential arrhythmia. The EMD also includes an analysis component configured to (1) identify a second portion of the first physiological parameter signal, where the second portion satisfies a discard criterion, (2) discard the second portion, and (3) perform an arrhythmia confirmation evaluation using a third portion of the first physiological parameter signal.

The present invention relates to a method of diagnosing whether a subject with no known history of atrial fibrillation is suffering from atrial fibrillation, or not, said method comprising the steps of a) determining the amount of a BNP-type peptide in a sample of said subject; b) comparing the amount the BNP-type peptide to a reference, and c) assessing intermittent ECG recordings obtained from said subject over a period of at least one week by using a handheld ECG device.

Methods and apparatuses, including devices and systems, for remote and detection and/or diagnosis of acute myocardial infarction (AMI). In particular, described herein are handheld devices having an electrode configuration capable of recording three orthogonal ECG lead signals in an orientation-specific manner, and transmitting these signals to a processor. The processor may be remote or local, and it may automatically or semi-automatically detect AMI, atrial fibrillation or other heart disorders based on the analyses of the deviation of the recorded 3 cardiac signals with respect to previously stored baseline recordings.

A medical device performs a method for detecting an atrial tachyarrhythmia by determining RR intervals between successive R-waves of a cardiac electrical signal and determining classification factors from the R-waves identified over a predetermined time period by determining at least a first classification factor correlated to variability of the RR intervals and a second classification factor indicating a presence of a ventricular tachyarrhythmia. The device classifies the cardiac electrical signal of the predetermined time period as unclassified, atrial tachyarrhythmia or non-atrial tachyarrhythmia by comparing the determined classification factors to classification criteria. The predetermined time period is classified as unclassified when the second classification factor indicates the presence of a ventricular tachyarrhythmia.

A medical device is configured to detect an atrial tachyarrhythmia episode. The device senses a cardiac signal, identifies R-waves in the cardiac signal attendant ventricular depolarizations and determines classification factors from the R-waves identified over a predetermined time period. The device classifies the predetermined time period as one of unclassified, atrial tachyarrhythmia and non-atrial tachyarrhythmia by comparing the determined classification factors to classification criteria. A classification criterion is adjusted from a first classification criterion to a second classification criterion after at least one time period being classified as atrial tachyarrhythmia. An atrial tachyarrhythmia episode is detected by the device in response to at least one subsequent time period being classified as atrial tachyarrhythmia based on the adjusted classification criterion.