A Small Step for Science

(Image from Cleveland Clinic)

Your humble blogger volunteered to be part of a medical study. However, in order to qualify I had to submit to a series of tests, not only to establish a baseline for future comparison but also to see if I met certain minimum health requirements.

Earlier this week I had difficulty passing the electrocardiogram (ECG). The "QT interval" was stuck between 475 and 480 when it had to be under 470. No matter what the technician and I tried, i.e., relaxing and slowing breathing, raising or lowering my back, removing the iPhone and Apple Watch, nothing worked. (On the previous day the reading was 494, and they gave me an injection of potassium and magnesium in order to remedy a shortage that can raise the QT interval.)

The Mayo Clinic: [bold added]

On an ECG, there are five waves. They use the letters P, Q, R, S and T.

Waves Q through T show the heart signaling in the heart's lower chambers.

The time between the start of the Q wave and the end of the T wave is called the QT interval. This is how long it takes for the heart to squeeze and refill with blood before it beats again. If the interval takes longer than usual to happen, it's called a prolonged QT interval.

(GE image)

GE Healthcare:

Just as there are many ways to correct the QT for heart rate, there have been numerous attempts to establish the upper limit of "normal" for a corrected QT interval.

Women have a slightly longer QT interval than men. This figure shows the 99% upper limit of normal of the QTc for men (470 msec) and women (480 msec).

Speaking of prolonging, this story has gone on long enough. Just as we were ready to concede defeat, I thought of my hearing aids, which were too small for the technician to notice and which, in any case, were not on her checklist of forbidden ECG items.

Upon their removal the QT interval fell all the way down to 446, well below the cutoff. Even before the study has begun, I'm already contributing to the advancement of science.