{'fraction_non_alphanumeric': 0.018495684340320593, 'fraction_numerical': 0.006781750924784217, 'mean_word_length': 5.1477272727272725, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Electrocardiographic Changes during Selective Coronary Angiography

During selective coronary angiography ECG was recorded in leads 1 and II in 95 consecutive patients with the purpose of studying the ECG changes invoked by the injection of 7 ml Urografin 60% (Schering). Marked but transient changes were seen, probably caused by the physico‐chemical properties of the contrast medium. The selective injection of the same volume of Ringer solution did not evoke any ECG changes. When a blood volume in the coronary circulation is replaced by contrast medium or Ringer solution, transient coronary hypoxia will result. This hypoxia, therefore, is not the cause of the ECG changes observed in coronary angiography. Selective coronary angiography appears to impair depolarization as well as repolarization, the latter being the most affected function. Absence of ECG response during coronary injections indicates severe coronary artery disease or the presence of a single coronary artery. Right coronary injection is followed by an increase in PQ interval; arrhythmias seldom occur but are more likely to appear during right than during left coronary injections. The changes observed in this series are increased QRS and QT duration, a shift in QRS axis in the frontal plane, which is clockwise during right and counter‐clockwise during left coronary injections. The QRS vector is doubled. The T axis rotates in the frontal plane towards + 120° during left and towards – 75° during right coronary injection. When the T axis has this direction before angiography, no shift in axis is seen during injection of contrast medium.