Augustus Desiré Waller (1856 – 1922) was a British physiologist who recorded the first ever electrocardiogram (ECG).
Luigi Galvani (1737 - 1798) Italian obstetrician, surgeon and anatomist. Discovered the physiological action of electricity and demonstrated the existence of natural electric current in animal tissue - "the electrical forces in muscular movements" or the 'animal electricity'
Walter Holbrook Gaskell (1847-1914) was a British physiologist central to our current understanding of cardiac physiology
Carl Friedrich Wilhelm Ludwig (1816-1895) German physician and physiologist. Designed advanced experimental laboratory, spawned many eponyms