Mackenzie, James (1848-1924)

Scottish physician and cardiologist who was a pioneer of modern cardiac medicine. He was the first to identify a large number of irregularities in the heart's beat and establish which were caused by serious disease and which were of no consequence. Knighted 1915.

In his work as a general practitioner he became interested in how a person's pulse is generated and invented an ink polygraph which enabled him to compare venous pulse, arterial pulse and the beat of the heart itself. He published The Study of the Pulse 1902 and Diseases of the Heart 1908. He realized that an important principal in some heart disease is to diagnose whether a heart is able to compensate for a disordered valve rather than to assume that all heart murmurs are totally debilitating.

Mackenzie was born in Scone, near Perth, and studied medicine at the University of Edinburgh.

Heartbeat Mackenzie was particularly interested in the total irregularity of the heartbeat which occurs in the later stages of the disease of the mitral valve, probably the commonest of all chronic heart conditions. He found that the characteristic wave caused by contraction of the auricles in the jugular vein was absent in mitral valve disease. This is because the muscle fibres are contracting independently of each other and at a rate that is far higher than that which can be conducted to the ventricles. Hence only some pulses get through at irregular intervals. This condition is now treated with drugs, or in the most severe of cases, by mitral valve transplant.