DESCRIPTION
Computerized 2-lead resting electrocardiogram analysis (e.g., multifunction cardiogram) is a computerized analysis of a 2-lead resting electrocardiogram that has been proposed for use as a diagnostic test for coronary artery disease (CAD). This policy will review the evidence on accuracy and clinical utility of the multifunction cardiogram.
The standard 12-lead resting electrocardiogram (ECG) has limited diagnostic accuracy in the detection of coronary artery disease. Because of its limited accuracy, the resting ECG has only a limited role in the diagnosis of chronic CAD. Stress testing, either at rest or with exercise, combined with single-photon emission computed tomography (SPECT) or echocardiographic imaging, is the most common initial test in the diagnostic work-up of chronic CAD. Sensitivities and specificities for stress testing vary, but generally fall in the 75%-90% range. Cardiac angiography is the gold standard for diagnosing CAD, and is used in situations where CAD needs to be confirmed following stress testing.
The multifunction cardiogram is intended to improve on the performance of the standard ECG for diagnosing CAD. The study device records a 2-lead EKG tracing for 82 seconds using leads II and V5 together with proprietary hardware and software. The analog EKG tracing is then amplified, digitized, down-sampled to a rate of 100Hz, and encrypted for digital transmission. The digitized information is transmitted to a central server for further analysis. At the central server, the tracings undergo a series of mathematical transformations and signal averaging. There are 6 mathematical transformations included: power spectrum, coherence, phase angle shift, impulse response, cross-correlation, and transfer function. Following these transformations, the patterns found in the tracing are compared to a large reference database collected by the manufacturer. A severity score is generated, indicating the likelihood that CAD is present. The severity score ranges from 0-20, with a score of 4.0 suggested as the cutoff for the presence of clinically significant CAD.
There is a least one commercially available device, the Multifunctional Cardiogram or MCG (previously called the 3DMP device), manufactured by Premier Heart, LLC (Port Washington, NY). In April 2003, the 3DMP device was cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process. The FDA determined that this device was substantially equivalent to existing devices for use in EKG analysis. Multifunction Cardiogram, or MCG
POLICY
Computerized 2-lead resting electrocardiogram analysis (e.g., multifunction cardiogram) for diagnosing coronary artery disease is considered investigational.
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ADDITIONAL INFORMATION
A total of 4 studies from 3 clinical series report on the accuracy of multifunction cardiogram for diagnosing CAD. These studies report sensitivities and specificities that are in the high range, with sensitivity ranging from 89.1%–94.8% and specificity in the range of 81.1%–88.9%. However, these studies have several limitations that limit their internal and external validity. In all of the studies, the population is a convenience sample of individuals who were already scheduled for angiography. These patient populations are thus subject to a referral or “work-up” bias in that the population of individuals that might be considered for the multifunction cardiogram in clinical practice is not the same population that is being referred for angiography. Also, the number of individuals enrolled but not included in the analysis was relatively high, ranging from 14.9%–32% of the total number of patients enrolled. This high rate of exclusion from analysis leaves the potential for a biased estimate of the sensitivity and specificity of the test. Finally, in one of the 3 series, the angiogram and multifunction cardiogram were not interpreted in an independent, blinded manner, thus potentially leading to additional bias.
There are no studies that attempt to determine the clinical utility of the multifunction cardiogram. Even if this test does have good accuracy for diagnosing CAD, its role in clinical practice would still need to be determined. Use of the multifunction cardiogram to screen for CAD would be a departure from usual practice, as screening for CAD has not been shown to improve outcomes. In the non-acute setting, the traditional resting EKG has a limited role in diagnosing CAD. The most common method for diagnosing CAD for this purpose is stress testing. There is no evidence comparing the accuracy of multifunction cardiogram to stress testing. The comparison to angiography, while useful from a research perspective, has a limited role in determining clinical utility given that multifunction cardiogram would not be used as a replacement for angiography. Because of these limitations, the evidence is not sufficient to determine the impact of the computerized 2-lead resting electrocardiogram analysis (e.g., multifunction cardiogram) on health outcomes, and therefore the use of this device is considered investigational.
SOURCES
BlueCross BlueShield Association. Medical Policy Reference Manual. (11:2010). Computerized 2-lead resting electrocardiogram analysis for the diagnosis of coronary artery disease (2.02.25). Retrieved January 12, 2011 from BlueWeb. (5 articles and / or guidelines reviewed)
ORIGINAL EFFECTIVE DATE: 4/24/2011
MOST RECENT REVIEW DATE: 4/24/2011
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