Eligibility of Subject studied -

The test subject was undefined and of arbitrary choice.

The test cases studied are 300, held at the Fortis hospital in Dehradun.

The test subject consent was taken prior to taking their test via SPANDAN ECG.

The objective of the study

To check whether the spandan detects the correct trace.

Eligibility of Spandan to perform with respect to 12 lead Goldstandard ECG.

Validating the AHA standards to evaluate the Trace with the help of the QT interval.

Introduction
According to AHA (American heart association), QT plays a major role in the detection of abnormalities in the ECG traces. The QT detectiongives rise to lethal ventricular arrhythmias. 5 Some regard differences of up to 50 ms in QT intervals measured in the various leads in normal subjects as being normal (Statters DJ, Malik M, Ward DE, Camm AJ. QT dispersion: problems of methodology and clinical significance. J Cardiovasc Electrophysiol. 1997; 5:672– 85) ; others have suggested that differences of up to 65 ms were still within the limit of normal.(Surawicz B. Will QT dispersion play a role in clinical decision-making? J Cardiovasc Electrophysiol. 1996; 7:777– 84.), if this measurement differs by more than 40 ms from that in other leads, the measurement may be in error, and measurements from adjacent leads should be considered.
Evaluation of QT intervals from sequential ECG recordings is essential for identification of QT prolongation induced by pharmacological agents in drug studies. It is also helpful as an adjunct to ST analysis in determining the presence of active ischemia in patients suspected of having myocardial infarction. Hence, QT is the limiting factor to evaluate the tracking accuracy of an ECG lead.

The Spandan ECG and results evaluated was 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 to test in the health camp organized by Fortis Hospital and Sunfox Technologies in Dehradun.

Methodology
The evaluation study was performed under the protocol set by the Spandan technical team, which was unbiased and partial and involve the involvement of Cardiologist and a physician. The QT interval was the limiting attribute of the evaluation of the results. It was aimed to achieve the minimum deviation in the lead 2 of Spandan ECG and GEMAC2000 Gold standard.
The test was taken in a subject with consideration of the following :-

The subject consent must be taken for the test.

There must be not the difference of five minuted 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 must be taken by 12 lead Gold standard at first.

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 is taken as positive if

the deviation between the 12 lead Goldstandard ECG and Spandan ECG deviates less than 65 ms (AHA recommended) with respect to each other.

The human error of 5% will be taken into consideration.

The Deviation in the 302 subjects is shown in the figure below. Through which there is the average standard deviation is +- 36.2 ms as compared to the 12 lead gold standard.

The figure below shows the data of the QT interval received in 302 tested subjects. The interval does not seem to vary beyond AHA permissible standards. The mean difference of QT interval in Spandan ECG with respect to 12 lead Gold standard is -1.200 ms. Which is under the Glasgow 12 lead ECG Measurement ECG norms. The Glasgow program detects the QT interval with a mean difference of -2.200 ms.


The accuracy was calculated by using the following formula:-

% Accuracy = (QT 12 lead Goldstandard-QT via Spandan)/(QT 12 lead Goldstandard) x100

The results obtained out of 302 subjects have 20 negative results, which were deviated above 65 ms in QTC interval;hence, the tracingaccuracy estimated for 302 subjects is 93%. The standard deviation is still in the permissible limits of 65 ms as recommended by AHA.

Conclusion and Scope

The Spandan ECG trace is 93% accurate as compared to the 12 lead Gold standard (GEMAC2000).

The Spandan ECG Trace meets the Glasgow measurement accuracy standards for QT Interval.

The QT interval deviation is the convenient way for validation of trace according to AHA.

Spandan ECG isconvenient to use for health and wellness monitoring and pre-event detection.