He retired from the British Heart Foundation (BHF)-sponsored Field Marshal Alexander Chair of Cardiovascular Medicine in 1994, but continued to work at the John Radcliffe Hospital in Oxford.
His work according to Microsoft Academic Search has been cited in over 40,000 papers and in hundreds of text books in the field of cardiology.
[7] Sleight was President of the World Hypertension League from 1995–2000[8] and served as chair of the ISIS group steering committee and the related coronary prevention studies coordinated by the Clinical Trials Service Unit in Oxford.
[11] In 1964, Consultant Cardiologist Dr Peter Sleight in conjunction with Cardiac Surgeon Dr Alf Gunning[12][13] from South Africa performed one of the first pioneering operations to install an external Lucas cardiac pacemaker on a patient in her early 30s at the Radcliffe Infirmary in Oxford.
The patient had previously spent many months connected to a filing cabinet size artificial heart machine known as the "fire engine" because of its red colour.
Sleight is accredited for being the first to carry out studies of the effect of Aspirin on cardiac function and stroke prevention in the early 1970s.
He served on several data monitoring committees of major clinical trials, including Gusto, ECLA, ASCOT, ADVANCE, EUCLID, MODEST, CREATE, OASIS 5–7, COMMIT, VALUE, PACE, SCOUT, RELY, ORIGIN, GISSI-HF, ONTARGET, TRANSCEND and PrOFESS.