As a medical professional with expertise in cardiology, I can explain that an ECG, or electrocardiogram, is a test that measures the electrical activity of the heart. The ECG is typically represented by a series of waves, each corresponding to a different phase of the heart's electrical cycle. The "boxes" you're referring to are likely the small squares on the ECG paper, which are used to interpret the heart's rhythm and rate.

Each small square on the standard ECG paper represents 0.20 seconds in time, and there are 5 small squares (or 1 large square) in a 3-second interval. The height of the squares represents voltage, with each small square being 1 millivolt in magnitude.

To calculate the heart rate from an ECG, you would count the number of large squares between two QRS complexes (the first and largest wave in the ECG complex, representing the depolarization of the ventricles). If there is one large square between QRS complexes, it corresponds to a heart rate of 300 beats per minute (bpm). If there are three large squares, it corresponds to a rate of 100 bpm. This is because there are 5 small squares in a large square and 3 large squares in a 6-second interval (since 6 seconds times 100 bpm equals 600 beats, which is the standard for calculating heart rate).

So, in terms of cost, ECG machines and the ECG test itself are priced based on various factors including the technology used, the brand, and the specific features of the machine. The cost of an ECG test at a medical facility will also depend on the location, the healthcare provider, and whether the patient has insurance coverage.

Please note that the information provided is a general explanation and the actual cost of an ECG or the interpretation of an ECG should be discussed with a healthcare provider or a medical billing department.

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The ECG paper speed is ordinarily 25 mm/sec. As a result, each 1 mm (small) horizontal box corresponds to 0.04 second (40 ms), with heavier lines forming larger boxes that include five small boxes and hence represent 0.20 sec (200 ms) intervals.read more >>