Harold M. Hastings

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It has become widely accepted that the most dangerous cardiac arrhythmias are due to re-entrant waves, i.e., electrical wave(s) that re-circulate repeatedly throughout the tissue at a higher frequency than the waves produced by the heart's natural pacemaker (sinoatrial node). However, the complicated structure of cardiac tissue, as well as the complex ionic(More)
We describe a useful setting for interactive, real-time study of mathematical models of cardiac electrical activity, using implicit and explicit integration schemes implemented in JAVA. These programs are intended as a teaching aid for the study and understanding of general excitable media. Particularly for cardiac cell models and the ionic currents(More)
This study is an anatomic investigation to define the architecture of and the stabilizing structures for the proximal radioulnar joint. Ten fresh-frozen cadaver elbows were dissected. Measurements of the radial head, annular ligament, radial fossa of the ulna, and interosseous membrane were made and were correlated to clinical observations of elbow(More)
A simplified quantitative ionic model of cardiac action potential, which reproduces accurate restitution curves, is used in conjunction with global tissue characteristics such as rotational cell anisotropy and periodic boundaries to study the transition from ventricular tachychardia (VT) to ventricular fibrillation (VF). We give an explanation for the(More)
Several studies have examined the normal range of wrist motion used to accomplish activities of daily living. Little information is present, however, on what functional limitations might be experienced by patients actually undergoing formal wrist arthrodesis. This study undertook comprehensive functional evaluation of 23 patients who underwent wrist(More)
Biological systems routinely solve problems involving pattern recognition and feature extraction. Such problems do not appear to admit similarly routine algorithmic solutions; the power of biological systems in this regard apparently arises from nonalgorithmic dynamics. It is our intention to explore, and to develop principles of, functional characteristics(More)
The distal radio-ulnar joint (DRUJ) is often the site of persistent symptoms after malunion of distal radius fractures. These malunions alter load transfer across the ulnocarpal joint, disturb DRUJ kinematics, and result in joint incongruity at the sigmoid notch. Treatment of distal radius malunions must not only correct position of the radial platform and(More)
Extensor lag is a common sequella of proximal phalangeal fractures. Proximal phalangeal fractures frequently lead to extensor tendon dysfunction via adhesions and phalanx malunion with angulation and/or shortening. The primary purpose of this study was to quantify the influence of proximal phalangeal angulation and shortening on proximal interphalangeal(More)