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Meaning and function of Multifunction cardiogram

Clicks:Updated:2015-11-09 10:11:15

Multifunction CardioGramTM (MCGTM) is the world's first Internet based non-invasive diagnostic tool that adopts Applied Systems Engineering prinicpals using Digital Signal Processing,i.e.DSP,Data-mining and Supervised Machine Learning to aid physicians to make rapid and much more accurate diagnosis of heart diseases.It is an FDA and AMA approved to diagnose myocardial ischemia due to Coronary Artery Disease (CAD).MCG extracts resting ECG data between the two electrical cources (leads V5 and II) to measure the interactions between Myocardium and intra-cardiac blood flow to accurately detect CAD without the stress,radiation,chemicals and invasiveness of the current modality set.This ground breaking Computational Systems Biology technology that will fundamentally change how heart disease is diagnosed.It is the culmination of the efforts of two generations of dedicated scientists,mathematicians,engineers and physicians over the course of three decades.MCG uses rapid,automated,cloud-based DSP applications,empirically derived digitized clinical database,and machine learning tools through the internet to give people around the world the access to the most accurate diagnostic system ever created,directly from primary care providers' offices or a patient's home,bypassing the need for costly and inaccurate imaging technologies currently in use in cardiologists' offices.

Function
The MCG test consists of an 82 second test where leads II and V5 resting cardiac electrical signals are collected,digitized,encrypted and sent to Premier Heart's data center.The data is then analyzed and transformed into multiple mathematical functions.These mathematical models produce a matrix based on 166 different indices that are then compared against a database of more than 40,000 patients with a broad range of clinically verified myocardial ischemia.A summarized report is returned to the physician via internet connection to the MCG unit in less than 10 minutes.

Performance of an MCG Test: A Four Step Process

MCG is performed in the following four steps.

Step 1:
Multiple cycles of complete resting ECG analog signals from leads II and V5 are recorded by a portable device from a patient at the point of care.The recorded signals are then digitized,encrypted and securely transmitted along with the patient’s demographic information to a central data center for processing.

Step 2:
The computers at the central data center perform a Fast-Fourier-Transformation of the signals from each lead,preparing them for a series of additional mathematical transformations.Research over the last three decades has demonstrated that these mathematical functions are able to extract physiological information embedded in between the two left ventricular leads,II and V5.



Step 3:
MCG mathematically transforms the complex non-linear information obtained in Step 2.The mathematical transformations employed include multiple non-linear mathematical functions such as auto and cross power spectra,cross-correlation,coherence,impulse-response and phase shift.These functions produce 166 indices.The index patterns from an individual patient are compared to similar patterns obtained from people whose MCG data has been entered into a large empirical database.This database consists of over 27,000 people with CAD,whose CAD status and severity is included in the database and has been confirmed by coronary angiography.Importantly,the database also contains MCG results from many patients who have one or more non-ischemic cardiac diseases.Therefore,the database is used to distinguish MCG patterns in patients with cardiac ischemia from MCG patterns in patients with non-ischemic cardiac disease and those with both cardiac ischemia and non-ischemic cardiac disease(s).Approximately 13,000 of the patients in the database have had normal coronary angiograms or have been determined to not have CAD after independent evaluations by two cardiologists.The database has been carefully accumulated over many years,and the MCG patterns of each entrant have been validated and correlated with the presence (or absence) and severity of CAD.The database has been designed to be robust and to minimize bias by including,among other things,49% of its data from women and an age range of 14-100 in the CAD and non-CAD groups,as well as people with many forms of heart disease (e.g.,arrhythmias,hypertrophy,cardiomyopathy),in addition to CAD.The database also contains other clinical and diagnostic data from all 40,000+ patients,including information about other non-cardiac disease entities.

Step 4: Based on the comparison to the reference database,an overall ischemia severity score (ranging from 0 to 20) is reported. (See Exhibit 4 for an overview of the MCG process).

Clinical Application
MCG data has been used to predict the findings of coronary angiography in several carefully designed and well-conducted prospective double-blind validation clinical trials (Grube 2007,Grube 2008,Weiss 2002,Hosokawa 2008,which are included as Exhibits 5,6,7 and 8,respectively).These trials were conducted in seven countries and three continents (North America,Asia and Europe).In these studies,MCG was performed on patients who were scheduled for elective coronary angiography by cardiologists who,on the basis of clinical impression and standard non-invasive testing,believed that the patients had an intermediate to high risk of having relevant coronary artery stenosis (CAS).Relevant CAS was defined as a 70% or greater stenosis of one or more major epicardial arteries or a 50% or greater occlusion of the left main coronary artery.The patients in these trials represent "real-world" care,much like the patients studied by Patel.In this regard,it is not surprising that the percentage of patients who were found to have relevant CAS in each of these trials was similar to the percentage who had relevant CAS in the Patel study.This means that even though the treating cardiologists believed that some patients in these four trials were at high risk for significant CAD,the patients studied in these trials were,in reality,at intermediate risk of having significant heart disease rather than at high risk.Therefore,these trial results are directly applicable to most patients seen with suspected CAD.These four trials of MCG were designed to compare the accuracy of MCG versus the accuracy of the standard of care (i.e.,clinical impression coupled with standard noninvasive testing) in predicting the existence of relevant CAS.This direct comparison to predict the findings of coronary angiography – the gold standard test - has never,to our knowledge,been published in the medical literature from 1949 to the present.The studies were all similarly designed as follows:

• All patients (n=1076) underwent MCG prior to coronary angiography for any indication.o Angiographers and staff at each study site were blinded to all MCG results and findings.• Coronary angiography was recorded digitally and underwent central review by two independent cardiologists who were blinded to the MCG results.(see Exhibit 9,the attestation,and the Curriculum Vitae,of the clinical trial monitor as to the appropriate blinding of the angiographic and MCG results from the relevant parties) • An MCG score of 4.0 or higher was considered indicative of a hemodynamically relevant coronary artery stenosis of >70% in at least one large-sized vessel.• All of the trials,whether single or multi-center from three continents in seven countries,produced statistically reproducible results.

Each of the trials had similar findings.Strobeck (2009,see Exhibit 10) combined the results of these studies into a meta-analysis that reported the following:

• MCG correctly classified 941 of the 1076 patients with or without relevant stenosis.• Sensitivity/specificity: 91.2%/84.6% (in agreement with above mentioned peer review published trials).• Positive/negative predictive value: 81.9%/92.6% (in agreement with above mentioned peer review published trials).• The results were similar across all studies and were not affected by sex,ethnicity,geographic location or Framingham risk score.

This diagnostic performance compares favorably to other non-invasive diagnostic tests.For example,a review of stress scintigraphy studies reported a wide range of sensitivities from 44%-89% and specificities of 89%-94% for 2+ vessel disease (Elhendy 2002,see Exhibit 11).Numerous studies of exercise echocardiography as a diagnostic tool for CAD have been conducted,and reported sensitivities range from 31% to over 90%,while specificities range from 46% to nearly 100% (Geleijnse 2007,Marwick 2009,Smart 2000.See Exhibits 12,13 and 14,respectively).These studies also show that these modalities are less accurate for patients with single vessel CAD.The inability of standard noninvasive diagnostic tests to accurately diagnose CAD in women has been a longstanding problem in cardiology.Importantly,in each of these trials,the sensitivity,specificity and positive and negative predictive values of MCG in predicting the existence of relevant CAS in women was just as good as it was in men.These data were recently published by Strobeck et al.2011 (see Exhibit 15) in a metaanalysis.The authors concluded that the sensitivity and specificity of MCG for detecting relevant CAD in women,as diagnosed by coronary angiography,appears to be equal to or better than those of other resting or stress ECG/imaging modalities.This may be because the database against which individual patient data is compared takes into account the physiological differences between males and females as well as physiological changes due to aging.This is accomplished by populating the database with approximately half of the data coming from women (normal women and women with heart disease),and by grouping the data by age group and sex (e.g.,men aged 51–60,61-70 and women aged 51–60,61-70,etc.).In other words,the MCG database design is both age and sex "normalized." In summary,these trials provide evidence that MCG is a clinically useful tool for assisting physicians in the diagnosis of CAD in women.Strobeck et al.(2011,see Exhibit 16) have also completed a Paired Comparison of MCG with stress single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in 165 consecutive patients who were at intermediate risk of having CAD based on clinical findings and who agreed to undergo both MCG and stress SPECT,followed by elective angiography if SPECT was abnormal or valvular heart disease was present.They represent the diagnostic experience of a typical "real world" cardiology practice.The definition of relevant CAS was the same as that used in the other studies.Similar to the above meta-analysis,an MCG score of <4 was used to indicate the absence of relevant CAD.A total of 116 patients with abnormal SPECT MPI tests,persistent chest pain or significant VHD were entered into the final analysis.

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