Category Archives: Science

Science

Article Review: A Chilling Tale by J.H. Indik

Hubmed Page: A Chilling Tale

This is an article about a clinical case of a man who went to an emergency room for diarrhea, and ended up having a heart attack. It goes on to analyze the odd ECG recordings he produced, describe how hypothermia was induced to minimize damage, and elucidate the origin of the problem. It’s a quick read at 3 pages, two of which consist primarily of ECG plots.

As a basic scientist who does mostly simulation work, I’m not very good at reading pathology from ECG readouts. However, I’m trying to read more clinical literature to become more familiar with the way cardiologists look at a heart’s electrophysiological function. This article points out a number of odd features of the subject’s ECG readout, and explains the sources of them. It’s a little over my head, but it should be valuable information as I try to learn more about this form of diagnosis.

New Articles on Virtual Electrode Polarization

Virtual Electrode Polarization (VEP) is an effect seen when an electrical field is applied across cardiac tissue. Large regions of positive and negative polarization manifest on the tissue surfaces, and sometimes within the depths of the heart. I’d link to the Wikipedia article on the term, but there is none. Perhaps I should write one.

Here are some recently-published articles on the subject:

  • N.H. Kuijpers et al. found that tissue irregularity increased the number of virtual electrodes in simulation. Given that VEP appears strongly at tissue borders, this is not surprising. It’s good to see a methodic investigation on the subject, though.
  • D.L. Beaudoin et al. investigated the arrhythmogenic effect of plunge recording electrodes in real cardiac tissue. They found that in some cases, the VEP caused by plunge electrodes could induce reentry. This encourages optical mapping studies of surface activity, and points to simulation as even more advantageous for studying electrical activity withinthe heart.
  • Fujian Qu and others from the Efimov lab found that ascending ramp defibrillation waveforms produce more pronounced VEP, thereby more effectively eliminating reentry. I had the pleasure of meeting Fujian this past fall, during our lab’s Post-Katina stay at Washington University. This approach promises to decrease the necessary defibrillation energy, which implies less damage on the heart from defibrillation shocks.

There are some other articles in my queue, but they are from 2004 and earlier. I’ll post more as they roll in.

Heart Disease Blog Disappears

The heart disease news blog that I linked to not long ago has mysteriously disappeared. Luckily, I still have the last few news items in my aggregator. Unluckily, they pretty much lack references now. Those that I can rediscover references for, I will post below:

  • High intake of vegetable protein linked with lower blood pressure – A recent epidemiological study found that a high intake of vegetable protein correlated with low blood pressure.
  • Low blood pressure might not be good if you already have some heart failure – where the article in the previous bullet points out what is normally considered advantageous — low blood pressure in a healthy system — it turns out that low blood pressure in heart failure is associated with higher mortality, per this American Heart Journal article.

That’s it. If you know why that blog was shut down, please comment or send me an email.