His research involves conducting RCTs and large registries in the fields of atrial fibrillation and cardiac devices. He was the lead author of the SIMPLE trial, published in the Lancet in 2015, which demonstrated that implantable defibrillators could be safely inserted without performing intra-operative defibrillation testing.

He was the lead author of the ASSERT trial, published in New England Journal of Medicine in 2012, demonstrating the increased stroke risk associated with sub-clinical atrial fibrillation detected by pacemakers. Thomson-Reuters recognized ASSERT as the 38th most-cited scientific publication in 2012 (#16 in Medicine).

He was principal investigator and chair of the Canadian Stroke Prevention Intervention Network (CSPIN), a ten-year network grant funded by the Canadian Institutes of Health Research, The Heart and Stroke Foundation of Canada and Industry. He is the past co-chair of the Canadian Cardiovascular Society’s Atrial Fibrillation Guidelines Committee. Jeff has published more than 185 manuscripts.