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L.2.02.406
Acoustic cardiography, or correlated audio-electric cardiography, is a technique that simultaneously records the electrical and acoustical aspects of the heart. By integrating the acoustic and electric properties, acoustic cardiography is intended to enhance the diagnostic ability of simple auscultation. The information from acoustic cardiography has also been used to optimize hemodynamic parameters for device placement, particularly with cardiac resynchronization therapy (CRT).
Acoustic cardiography utilizes 3 inputs: a single electrocardiogram (EKG) lead from 2 standard electrodes, and 2 audio sensors placed at the usual V3 and V4 positions on the chest. These 3 channels synchronously record electrical and audio information. The audio information is processed using wavelet signal processing techniques and a diagnostic algorithm that filters out extraneous noise and uses time-frequency analysis to objectively define the heart sounds and the intervals between sounds. An analogue visual display of the audio data is then displayed and paired with the electrical data from the EKG recording.
Output from acoustic cardiography can generate numerous parameters, some of which may have clinical applicability. Three of these measures are:
S3 strength—a quantitative measure of the intensity of the S3 heart sound, which is an abnormal sound that is associated with systolic dysfunction;
Electromechanical activation time (EMAT), defined as the interval between the onset of the QRS complex and the closure of the mitral valve. EMAT is the main parameter that is used to optimize CRT therapy by choosing the interval that optimizes cardiac output;
Left ventricular systolic time (LVST)—the interval between mitral valve closure and aortic valve closure. This length of the LVST has been correlated with changes in ejection fraction.
Auscultation for an S3 is part of the physical exam when evaluating for presence of heart failure. The presence of an S3 indicates systolic dysfunction and is a specific physical exam finding supporting systolic heart failure. The S3 is an indistinct sound that can be difficult to hear and is not present in all patients with systolic dysfunction. Other components of the diagnostic evaluation for heart failure include a variety of clinical symptoms and physical exam findings such as dyspnea, orthopnea, pulmonary rales, increased jugular venous pressure, and peripheral edema. Routine diagnostic evaluation for heart failure also includes measurement of brain natriuretic peptide (BNP) and other common laboratory measures, and a chest x-ray. A direct measure of ejection fraction by echocardiography, nuclear medicine imaging, or other imaging modalities is a crucial component of clinical evaluation for heart failure. Systolic dysfunction can be confirmed by echocardiography and/or other imaging modalities.
Optimization of CRT therapy is usually done using Doppler echocardiography. Optimization involves manipulation of the atrio-ventricular (AV) and interventricular (VV) pacer settings in order to maximize left ventricular (LV) filling and stroke volume. Some evidence has reported that optimization improves overall clinical benefit, but these data are not uniform. Also, the question of whether re-optimization should be performed following initial optimization is controversial, as is the timing of re-optimization if it is performed.
The Audicor™ system and electrodes received 510(k) marketing clearances from the U.S. Food and Drug Administration (FDA) for “use in acquiring, analyzing and reporting EGG and heart sounds (phonocardiograph) data and to provide interpretation of the data for consideration by physicians.”
Zargis Acoustic Cardioscan (ZAC) received 510k clearance in May 2004. It is described as an electronic auscultatory device, intended to provide support to physicians in the evaluation of heart sounds in patients. The product will acquire and record the acoustic signals of the heart and analyze these signals. The analysis procedure will identify specific heart sounds that may be present. Identified sounds include S1, S2, and suspected murmurs. The device is indicated for use in a clinical setting, by a physician or by trained personnel who are acting on the orders of a licensed physician. It is not intended as a sole means of diagnosis. Interpretations of heart sounds offered by the Zargis Acoustic Cardioscan are only significant when used in conjunction with physician over-read as well as consideration of all other relevant patient data. (FDA, Indications for Use).
CADence received 510k clearance in August 2017. It is described as a “digital stethoscope used to record cardiac sounds, with integrated sensors used to record electrical activity of the heart (ECG)….” The indications go on to state that, “The CADence system is not intended to be a stand-alone diagnostic device. It does not supersede the judgment of the clinician.”
A related medical policy is Biventricular Pacemakers (Cardiac Resynchronization Therapy) for the Treatment of Heart Failure .
Acoustic cardiography and correlated audio-electric cardiography are considered investigational for the diagnosis of heart failure and for the optimization of CRT hemodynamic parameters.
Federal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.
07/21/2011: Approved by Medical Policy Advisory Committee.
07/17/2012: Policy reviewed; no changes.
10/15/2013: Policy reviewed; no changes.
07/02/2015: Code Reference section updated for ICD-10.
12/31/2015: Code Reference section updated to add CPT code 93799.
06/08/2016: Policy number L.2.02.406 added.
10/05/2017: Code Reference section updated to remove deleted CPT codes 0223T, 0224T, and 0225T.
07/24/2020: Policy reviewed. Policy statement unchanged. Sources updated.
11/01/2022: Policy description updated regarding devices. Policy statement updated to add "correlated audio-electric cardiography" as investigational for the diagnosis of heart failure and for the optimization of CRT hemodynamic parameters. Code Reference section updated to add CPT code 0716T.
08/07/2023: Policy reviewed; no changes.
08/19/2024: Policy reviewed; no changes.
Blue Cross and Blue Shield of South Carolina
Code Number | Description |
CPT-4 | |
0716T | Cardiac acoustic waveform recording with automated analysis and generation of coronary artery disease risk score |
93799 | Unlisted cardiovascular service or procedure |
HCPCS | |
ICD-10 Procedure | |
ICD-10 Diagnosis |
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