White Paper on Validating the detection of Artrial and Ventricular Abnormalities with Arrhythmia test in Spandan ECG

Nitin Chandola

Posted on - July 16, 2019

Eligibility of Subject studied -

  • The test subject was considered with the arrhythmic cardiac conditions. and of arbitrary age group.
  • The test cases studied are 153, held at the Fortis hospital in Dehradun.
  • The test subject consent was taken prior to taking their test via SPANDAN ECG.
  • The Test cases are classified under the two categories

  • a. Atrial Abnormality (AA)
    Under Atrial Abnormality, the following cases will be summarised in Arrhythmia test and the 7 lead ECG test via Spandan
    1. AR
    2. AFIB
    3. AFL
    4. AT
    5. MAT
    b. Ventricular Abnormality(VA)
    Under Ventricular Abnormality, the following cases will be summarised in Arrhythmia test and the 7 lead ECG test via Spandan
    1. VR
    2. V FIB
    3. VFL
    4. VT
    5. AVB

    The objective of the study
  • To check whether the Spandan detects the Heart defects in Lead 2testing.
  • Eligibility of Spandan to perform with less false positives in results with respect to 12 lead Gold standard ECG.
  • Validating the AHA and FDA standards to evaluateHeart defect detectionby Specificity and Sensitivity.


  • Introduction
    Heart defects detection is the important feature of Spandan ECG which is capable of evaluating the ventricular and atrial defects in the rhythm.Hence, a validation study was conducted to validate the specificity and sensitivity of results produced by the Spandan ECG with respect to 12 lead Gold standard. According to FDA andAHA standards, the specificity and sensitivity is the correct method to evaluate the accuracy of the results provided by any smartphone based ECG machine.

    Besides this, the study evaluates the Negative Predicted Values (NPV) and Positive Predicted Values (PPV).
    The Spandan ECG and results were evaluated and tested with respect to the 12 lead gold standard ECG. The machine that is used here for validation of the results is GEMAC2000, which was used for testing in the health camp organized by Fortis Hospital and Sunfox Technologies in Dehradun. Medical devices are classified into Class I, II and III. In terms of a regulatory requirement, Class I is controlled the least while Class III is controlled the most.
    Class, I are generally simple devices that pose minimal risk to the users like enemas, bedpans and elastic bandages. Whereas Spandan will surely attain the class II category in FDA regulations.

    Hence the premarket notification is important from the FDA. Hence a low false positive is the requirement to create a surety of performing well.Clinical investigations section includes study protocols, safety, and effectiveness data, adverse reactions and complications, device failures and replacements, patient information, patient complaints, tabulations of data from all individual subjects, results of statistical analyses, and any other information from the clinical investigations. An investigational device exemption (IDE) allows the investigational device to be used in a clinical study in order to collect safety and effectiveness data. Clinical studies are most often conducted to support a PMA.

    Methodology
    The evaluation study performed was under the protocol set by the Spandan technical team, which was unbiased and partial and involve the involvement of Cardiologist and a physician.FDA’s Clinical investigations section includes study protocols, safety, and effectiveness data, adverse reactions and complications, device failures and replacements, patient information, patient complaints, tabulations of data from all individual subjects, results of statistical analyses, and any other information from the clinical investigations. An investigational device exemption (IDE) allows the investigational device to be used in a clinical study in order to collect safety and effectiveness data. Clinical studies are most often conducted to support a PMA.
    As per the FDA regulations, Clinical evaluation of devices that have not been cleared for marketing requires:
  • informed consent from all patients;
  • labeling stating that the device is for investigational use only;
  • monitoring of the study and;
  • required records and reports.


  • The Interpretation of Heart defects by Spandan was taken as the characteristic attribute for the validation study. The study was aimed to achieve the minimum deviation in the lead 2 of Spandan ECG and GEMAC2000 Gold standard.
    The tests were performed in the subjects with consideration of the following protocols:-
  • The subject consent must be taken for the test.
  • There must be not the difference of five minutes between the test taken by Spandan ECG and GEMAC2000.
  • The cases with baseline wander are excluded.
  • Cases with motion artifacts are excluded from results.
  • Cases with wrinkled skin are excluded.
  • People with chest pain are included in the study.
  • Normal cases are also included.
  • The test reports must be taken by 12 lead Gold standard at first.

  • The following are the combinations used as True Positives and False Positives, True Negatives and False Positives.
    The spandan/12 lead Goldstandard Abnormal/NSR Abnormal/Defect Normal/NSR Normal/Defect
    Abnormal/NSR true true true false
    Abnormal/Defect true true false true
    Normal/NSR true false true true
    Normal/Defect false true true true


    The spandan/12 lead Goldstandard Atrial Abnormality Ventricular Abnormality No Abnormality
    Atrial Abnormality Positive Negetive Negetive
    Ventricular Abnormality Negetive Positive Negetive
    No Abnormality Positive Positive Positive

    Note* The result is concluded positive and negative taking hierarchy of 12 lead Gold standard ECG.

    Following are the considerations in the diagnosis of arrhythmic cardiac conditions in the clinical trials:-
    1. Atrial fibrillation and flutter with left bundle branch block aberration referred as ventricular tachycardia.
    2. Left ventricular hypertrophy is a maladaptive response to chronic pressure overload and an important risk factor for atrial fibrillation, diastolic heart failure, systolic heart failure, and sudden death in patients with hypertension. Hence LVH and AFIB could lead to a positive result.
    3. Aberrant conduction is not a mechanism of arrhythmia; it is a ventricular conduction disturbance, hence It is described under Ventricular Abnormality
    4. Ventricular tachycardia is a well-known complication of myocardial ischemia and may be provoked by exercise; many patients may appreciate only angina and be unaware of the unduly rapid heart rate that precipitates it. Hence Normal sinus rhythm with Ischemia is taken into the Ventricular Abnormality.
    5. The ECG showed atrial fibrillation and LBBB with intermittent left axis deviation or atrial fibrillation and LBBB with intermittent right axis deviation. Hence AFIB with Bundle Branch Block will stand positive to Left axis deviation and right axis deviation.
    6. Myocardial infarction (MI) is associated with the development of atrial fibrillation (AF). We aimed to characterize the atrial abnormalities because of MI and determine the role of ischemia to the AF substrate.

    The results will be visualized in Three forms:-
    1. Specificity and sensitivity in detecting Atrial Abnormalities
    2. Specificity and sensitivity in detecting Ventricular Abnormalities

    The data with the following combinations of results were neglected and reclassified as normal or abnormal:-
    1. Borderline ECG in Spandan and Borderline ECG in 12 lead Gold standard is True result.
    2. Borderline ECG in Spandan and Abnormal ECG in 12 lead Gold standard is a true result.
    3. Borderline ECG in Spandan and Normal ECG in 12 lead Gold standard is the true result.
    4. Abnormal ECG in Spandan and Borderline ECG in 12 lead Gold standard is a true result.
    5. Normal ECG in Spandan and Borderline ECG in 12 lead Gold standard is the true result.

    Here are the steps to be followed by the researcher for the validation as shown in the flow chart:-

    Results and Discussions
    The test performed will be evaluated with a human error of 5% will be taken into consideration.
    The Deviation in the 153 subjects is shown in the figure below. Through which there is an accuracy of 98.5 percent in interpreting the Abnormality and normality in the cases.
    Total cases True Detection False detection
    153 150 3
    Accuracy 98.5% (With Human Error) 3



    The Deviation in the 153 subjects is shown in the figure below. Through which there is an accuracy of 89.5 percent in interpreting the Cardiac defects in the cases.

    Total cases Positive Detection Negative detection
    153 137 16
    Accuracy 89.5% (With Human Error) 3




    As per the AHA, there isnocomputerprogram that can provide the correct interpretation as a skillful physician, hence the challenge was to bring the accuracy as near to the 12 lead Gold standard ECG.
    Hence, with the recommendation of FDA and AHA the Specificity, Sensitivity, PPV and NPV are calculated for three classified cases, i.e.
  • Overall specificity and sensitivity in detecting defects.
  • Specificity and sensitivity in detecting Atrial Abnormalities
  • Specificity and sensitivity in detecting Ventricular Abnormalities
  • This consideration was taken due to the in-depth analysis of the accuracy of Spandan in delivering better and accurate results as the 12 lead Gold standard. The number of cases taken into consideration is classified as-
    12 lead Goldstandard Abnormal Cases Normal Cases Borderline cases
    Number of cases 91 54 8


    the patient when the test is negative.

    A. Specificity and sensitivity in detecting Atrial Abnormalities
    Hence The Confusion matrix was given as

    The spandan/12 lead Goldstandard ECG (number of cases.) True Results False Results
    Positive Detection True Positive (13) False Positive (0)
    Negative Detection True Negative (1) False Negative (0)

    The Specificity is calculated by
    Specificity= (True Negative)/(True Negative+False Positive)

    Hence, Spandan is 100% specific in nature i.e Probability of detecting a negative test when the defect is absent.
    The Sensitivity is given as
    Sensitivity= (True positive)/(True Positive+False Negative)

    The calculated sensitivity of spandan in the detection of Cardiac defect is 100%. Hence, the probability of detection of disease when a cardiac defect is present is 100%.
    The Positive predictive value by Spandan ECG and Spandan Intelli Technology is given by
    PPV=(True positive)/(True Positive+False Positive)

    The obtained PPV for 14 clinical trial cases is 100 %.Hence, the probability of the patient having the disease while the test is positive is 100%.
    The Negative Predictive Value by Spandan ECG is given by
    NPV=(True Negative)/(True Negative+False Negative)

    The obtained NPV is 100 %, which can be interpreted as the probability of not having a disease to the patient when the test is negative.

    B. Specificity and sensitivity in detecting Ventricular Abnormalities

    Hence The Confusion matrix was given as

    The spandan/12 lead Goldstandard ECG (number of cases.) True Results False Results
    Positive Detection True Positive (25) False Positive (1)
    Negative Detection True Negative (2) False Negative (1)
    The Specificity is calculated by
    Specificity= (True Negative)/(True Negative+False Positive)

    Hence, Spandan is 66.6% specific in nature i.e Probability of detecting a negative test when the defect is absent.
    The Sensitivity is given as
    Sensitivity= (True positive)/(True Positive+False Negative)

    The calculated sensitivity of spandan in the detection of Cardiac defect is 96.1%. Hence, the probability of detection of disease when a cardiac defect is present is 96.1%.
    The Positive predictive value by Spandan ECG and Spandan Intelli Technology is given by
    PPV=(True positive)/(True Positive+False Positive)

    The obtained PPV for 14 clinical trial cases is 96.1 %.Hence, the probability of a patient having the disease while the test is positive is 96.1%.
    The Negative Predictive Value by Spandan ECG is given by
    NPV=(True Negative)/(True Negative+False Negative)

    The obtained NPV is 66 %, which can be interpreted as the probability of not having a disease to the patient when the test is negative.

    Case OVERALL DEFECTS ATRIAL ABNORMALITIES VENTRICULAR ABNORMALITIES
    Specificity(%) 100 100 66.6
    Sensitivity(%) 97.8 100 96.1
    NPV(%)) 81.5 100 96.1
    PPV(%) 100 100 66.1


    Conclusion and Scope
    FDA recommends that the statistical method of measuring the sensitivity, Specificity, PPV, and NPV is the right method to validate the real-life use of the medical device. Hence, these values are in the standard range to provide an accurate measure of cardiac disease. The spandan settles a good practice in the clinical trial of predicting the high positive values, hence it could withstand the OPD’s and Pre and post-surgery monitoring. The spandan also shows the tendency to detedct Atrial and Ventricular abnormalities effectively. As the Number of cases is enough to justify its result’s effectiveness, The Detection of Ventricular Abnormality has a fraction of False positive, due to which Spandan should not be used while making any surgical conclusions, Hence processof 12 lead Goldstandard and chmical Enzyme test is preffered for Surgical cases .This device can be helpful to Physicians and Health conscious individuals.