Objective: Evaluate correlations between variations in eletrocardiogram (ECG) recordings and acute myocardial infarction.
Methods: Use of a low-cost software to digitalize printed and/or ".pdf" file format ECG recordings. Calculation of ST-segment area and amplitudes of the J and Y points.
Results: The amplitude of the Y point holds maximum correlation with troponin concentration. ST-segment elevation is not a good statistical indicator of myocardial infarction severity. There is a strong negative correlation between the amplitude of the J point and the amount of magnesium ions, but no statistical correlation with sodium or calcium ions. Neither method for calculating the ST-segment area (pixel counts and interpolation) indicated any significant differences in the results.
Conclusion: The software used proved to be functional and cost-effective. Y point amplitude is a sensitive marker of myocardial infarction, and is also a calculation method both simpler to use and less subject to error than the calculation of the ST-segment elevation area.