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Systems and methods for tuning, analysis and display of heart sounds

Systems and methods for tuning, analysis and display of heart sounds description/claims

This is a continuation-in-part of co-pending U.S. application Ser. No. 11/740,906 filed on Apr. 26, 2007, entitled “Systems and Methods for Analysis and Display of Heart Sounds”, which is hereby fully incorporated by reference.

This invention relates generally to medical electronic devices for analysis of auscultatory cardiac sounds. More particularly, this invention relates to a method for transducing, intelligently filtering, recording, analyzing and audiovisual representation of heart sounds at the point of care, in humans, to enable differential diagnosis.

Auscultatory sounds have long been one of the primary inputs to aid in the detection of various physiological conditions. For instance the stethoscope is the first tool used by a clinician to monitor heart sounds to detect and diagnose the condition of a subject's heart. Auscultation itself is extremely limited by a number of factors. It is extremely subjective and largely depends on the clinician's expertise in listening to the heart sounds and is compounded by the fact that certain components of the heart sounds are beyond the gamut of the human ear. In addition, auscultation relies on correctly determining which of the primary heart sounds correspond to the systolic and diastolic phases of the heart. This is made more difficult when conditions such as ectopic beats, atrial fibrillation, atrial flutter, tachycardia and various other rhythmic disorders occur.

A number of improvements have been developed to circumvent such bottlenecks, ranging from relatively noise-free electronic auscultation, to complex computer algorithms that can analyze the cardiac sounds, calculate various numerical values like heart rate, ascertain the heart sound phases, etc. For example, algorithms are available that allow heart sounds in electronic format to be visualized on a personal computer screen and analyzed.

Accordingly, personal computer (PC) based auscultatory devices like the Acoustic Cardioscan from Zargis Medical Corporation of Stamford, Conn., and software packages like the Veteran Phonocardiograph monitor from BioSignetics Corporation of Exeter, N.H., are capable of a wide range of operations and manipulations of heart sounds offline. However, the above described PC based platforms suffer from the following shortcomings and bottlenecks. These PC based systems call for a separate data gathering device to record heart sounds in the format that can be processed by the PC based algorithm. In addition, there is a critical time delay between the time the clinician auscultates the subject and the time the clinician applies the PC based analysis to the recorded heart sounds. There are also portability issues associated with the PC based system setup.

Currently, handheld auscultatory devices have been developed in an attempt to circumvent some of the above described problems with PC based computer systems. These handheld devices do incorporate the data gathering mechanism in the device itself, obviating the need for separate data gathering. Handheld devices sold under the brand names Cadiscope (from Caditec AG Medical Instruments of Switzerland) and the Visual Stethoscope (from MC21 Meditech Group) are instances of such handheld auscultatory devices. However handheld devices have their own shortcomings. For example, some handheld devices are designed such that the chest piece is housed in the device itself thereby rendering sterilization processes difficult, or at least call for involved and expensive methods of cleaning. Further, the mere display of the heart sounds or ECG signals, in addition to the audio of the heart sounds is insufficient for the user to ascertain the condition of the heart.

Particularly, there is a long felt and unmet need for the ability for such handheld auscultatory devices to dynamically alter the various filters used in processing the heart sounds. Such filtering, or ‘tuning’ may include user selection of filters, preset bands of filters and intelligent filtering.

It is therefore apparent that an urgent need exists for an improved auscultatory device that is easy to use, accurate, portable, cost-effective, tunable and easy to sterilize and maintain.

To achieve the foregoing and in accordance with the present invention, a method and system of tuning, analyzing and displaying heart sounds is provided. Such an auscultation system is useful for a clinician to efficiently and cost-effectively auscultate patients.

In some embodiments, the tunable auscultation system includes a heart sound transducer for sensing heart sounds from at least one chest location of the patient. The heart sounds are then passed through a circuit which pre-condition the signal. The pre-conditioning circuit consists of a pre-amplifier and an anti-aliasing filter.

These heart sounds are then sent to an analysis tool which performs a set of filtering processes. This tuning includes extracting pathology information.

The analysis tool is able to filter the frequencies of the heart sounds. The analysis tool is able to take in user input, perform intelligent tuning, and provide appropriate user feedback.

The user of the device is able to input a desired filter combination, consisting of either preset filter setups, e.g. low, medium, high, emphasize a certain feature such as S1 or S2, bell, diaphragm and various other settings whose frequencies are well known, or the user can set the center frequency and filter bandwidth as they desire, with or without the device providing guidance.

The intelligent tuning section consists of an algorithm that analyzes the signal, segments it into its various component parts, and extracts the segments of interest. The segments of interest can then be used by the algorithm to determine whether there is an underlying pathology. The intelligent tuning section can then pass this determination to the output section for user interaction.

The output of the stethoscope can consist of a signal strength indicator, a diagnosis indicator, the phonocardiogram and various methods of displaying a processed version of the phonocardiogram. The diagnosis indicator utilizes the information produced by the intelligent tuning section.

These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures.

• Provisional Patent
• Utility Patent

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