Has anyone ever had a Cerebral Angiogram?

What is the scribble on the first angiogram?

• In radiography class last week, we looked at a picture of the very first angiogram ever (sorry, I don't have time to post a link to it here, but if you do an image search for it on Google, it's very obvious due to the irregularity described below). Dye was injected into the veins of the hand of a cadaver and then radiographed. The vasculature is all very normal except for the index finger. It looks as though the veins in the proximal phalanx of the index finger circle the digit several times. Since this is not normal, I asked the professor and they didn't know what would even make it look like that. Anyone out there have any ideas or even know for sure?

• Answer:

  I am a Vascular Surgeon so this is my forte. When cell membranes in the heart depolarise, voltages change and currents flow. Because a human can be regarded as a bag of salt water (with baad attitude), in other words, a volume conductor, changes in potential are transmitted throughout the body, and can be measured. When the heart depolarises, it's convenient (and fairly accurate) to represent the electrical activity as a dipole --- a vector between two point charges. Remember that a vector has both a size (magnitude), and a direction. By looking at how the potential varies around the volume conductor, one can get an idea of the direction of the vector. This applies to all intra-cardiac events, so we can talk about a vector (or axis) for P waves, the QRS complex, T waves, and so on. ECG paper is traditionally divided into 1mm squares. Vertically, ten blocks usually correspond to 1 mV, and on the horizontal axis, the paper speed is usually 25mm/s, so one block is 0.04s (or 40ms). Note that we also have "big blocks" which are 5mm on their side. But always remember that in the heart, because we have two electrically `isolated' chambers, the atria and ventricles, that we are really looking at two rates --- the atrial and ventricular rates! It just so happens that in the normal heart, the two are linked in a convenient 1:1 ratio, via normal conduction down the AV node. In disease states, this may not be the case. The peculiar system we use in electrocardiography is non-Cartesian, and rather arbitrary! We measure the direction of vectors in degrees, and zero is indeed facing `East', but +90o is South, instead of North as it would be in a Cartesian system. You can work out that ± 180o is 'West', and that minus 90o is 'North'. The rhythms are ups and downs of the beat, so each ectopic is regarded as the rhythm. The question isn't much clear so I explained a basic premier of a EKG reading of several inter-vascular problems.