Effect of pulse palpation on cardiac arrhythmia in coronary care patients.

In a study of 62 coronary care patients, 31 of whom exhibited types of cardiac arrhythmia, the frequency of ectopic beats changed significantly when a nurse palpated the pulse. This finding suggests that autonomic responses to human contact can significantly alter the rate of ectopic impulse generation. These findings further suggest that studies of cardiac arrhythmia should attend to the nature of the social field in which data are collected.     

Changes in muscle fiber conduction velocity, mean power frequency, and mean EMG voltage during prolonged submaximal contractions

Average muscle fiber conduction velocity, mean power frequency, and mean EMG voltage have been measured in human vastus lateralis during prolonged isometric knee extensions at 10, 20, 30, and 40% of the maximum knee extension force. During contractions at 10 and 20% of maximum force, conduction velocity and mean power frequency rose as the contraction progressed, whereas the conduction velocity and mean power frequency fell at 30 and 40% of the maximum force. The mean EMG voltage rose during the contractions, with steeper increases for higher forces. It is argued that two principal factors influence the EMG during prolonged submaximal contractions: firstly, the fatigue of current active motor units, and, secondly, recruitment of fresh motor units. These factors act in opposition to muscle fiber conduction velocity. Recruitment gives an increase in average conduction velocity, whereas fatigue provokes a slowing in conduction velocity.     

Occipital alopecia following cardiopulmonary bypass.

Postoperative alopecia is a minor complication of surgery but a cosmetic disaster to the patient. Over a 3 year period, 60 cases of occipital alopecia were discovered in patients following open-heart surgery and 5 cases on other surgical services. In contrast to previous reports, 29 patients had alopecia one year later, presumed to be permanent. Extensive operations, with prolonged recovery and elective overnight mechanical ventilation, were common to all. Retrospective analysis and prospective studies clearly demonstrated that localized scalp pressure was the cause of the alopecia and that the duration of pressure determined the extent of the damage. Moving the patient's head at regular intervals during operation and recovery eliminated the alopecia. The type of head rest used did not modify the development of alopecia. Electrical injury and the use of heparin, hypothermia, electrocautery, or hypotension were eliminated as possible causes. Conclusive evidence correlating periperative events with the formation of pressure sores in man has not been previously reported.     

Valvulotomy of valves in the saphenous vein graft before coronary artery bypass.

Occasionally, repeat angiograms disclose turbulence, with or without clot formation, at the valve sites in saphenous veins used as coronary artery bypass grafts. A simple valvulotomy may be used to split these valves to allow a more even flow and to avoid the valve recess where air may be trapped or thrombus formed. A potential cause for perioperative infarction or graft failure may thus be avoided.