Thomas Lewis

Sir Thomas Lewis (1881 – 1945) was a Welsh cardiologist.

  • Born on December 26, 1881 in Cardiff, Wales
  • 1902 – BSc University College, Cardiff,
  • 1927 – Suffered first heart attack and gave up his ’70 a day’ habit recognizing before others did that ‘smoking injures the blood vessels.’
  • 1935 – Suffered a second heart attack and remarked ‘..another arrow from the same quiver my friend, and one of them will get me in the end’
  • Died 17 March 1945 of myocardial infarction. Buried in Llangasty churchyard, Breconshire, Wales, overlooking Llangorse Lake, where he fished and studied nature as a young boy.

Medical Eponyms
Lewis lead (S5-lead) (1913)

The Lewis lead configuration can help to detect atrial activity and its relationship to ventricular activity. Useful in observing flutter waves in atrial flutter; and detecting P waves in wide complex tacharrhythmia to identify atrioventricular dissociation

Lewis lead placement
  • Right Arm (RA) electrode on manubrium
  • Left Arm (LA) electrode over 5th ICS, right sternal border.
  • Left Leg (LL) electrode over right lower costal margin.
  • Monitor Lead I
Lewis Lead ECG placement AV dissociation
Lewis lead (S5-lead) placement
History of the Lewis Lead

Thomas Lewis (1881-1945) developed and described (1913) his lead configuration to magnify atrial oscillations present during atrial fibrillation [Lewis T. Auricular fibrillation. In: Clinical Electrocardiography. 1913: 86-97]

Key Medical Attributions

Einthoven acknowledged Lewis in his 1925 Nobel Prize acceptance speech:

…Thomas Lewis, who has played a great part in the development of electrocardiography deserves a special mention. It is my conviction that the general interest in ECG would certainly not have risen so high, nowadays, if we had had to do without his work, and I doubt whether without his valuable contributions I should have the privilege of standing before you today.

Einthoven 1925

Major Publications


eponymictionary CTA


the names behind the name

Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

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