1892

First clinical polygraph made for James Mackenzie in London (Mair, 91ff.). In his case of Mrs. Ashworth, Mackenzie likely makes the clinical inference of ventricular extra-systoles, (premature heart beat when chambers beat out of order leading to momentary arrhythmia) as cause of cardiac irregularity (Mair, 132; Wilson, 85-87 gives dates as 1890).