George Mines was a pioneering physiologist who, despite an extremely short period of professional activity and only primitive experimental methodology, succeeded in formulating concepts that continue to be of great influence today. Here, we review some of his most important discoveries and their impact on contemporary concepts and clinical practice. Mines’ greatest contribution was his conceptualization and characterization of circus movement reentry. His observations and ideas about the basis for cardiac reentrant activity underlie how we understand and manage a wide range of important clinical rhythm disturbances today. The notions he introduced regarding the influence of premature extrastimuli on reentry (termination, resetting and entrainment) are central to contemporary assessment of arrhythmia mechanisms in clinical electrophysiology laboratories and modern device therapy of cardiac tachyarrhythmias. Refinements of his model of reentry have led to sophisticated biophysical theories of the mechanisms underlying cardiac fibrillation. His seminal observations on the influence of electrolyte derangements and autonomic tone on the heart are relevant to our understanding of the physiology and pharmacology of arrhythmias caused by cardiac pathology. In this era of advanced technology, it is important to appreciate that ideas of lasting impact come from great minds and do not necessarily require great tools.
Mine's major contribution to the field of cardiac electrophysiology was the notion of circus movement reentry, a concept with far-reaching theoretical and clinical applications that remains highly relevant in modern electrophysiology. His model of cardiac fibrillation based on circus movement reentry paved the way for modern theories of fibrillation such as leading circle and spiral wave reentry. Mines was also instrumental in developing the notion of the vulnerable period of the cardiac cycle, the time window during which an extra-stimulus can trigger fibrillation, which forms the basis of several practical applications (e.g., synchronized cardioversion and pacemaker sensing function). Other noteworthy contributions include the description of the effects of metabolic abnormalities and vagal nerve stimulation on the electrocardiogram. Presently-used practical clinical applications resulting from Mines' discoveries are shown in the grey boxes.