5 August - 30 September 1984. Internal medical doctor at the Department of Cardiovascular Surgery, Stanford University School of Medicine, Stanford, USA.
1 October 1986 - 10 September 1991. Employed full time and paid as Research Fellow/Registrar with clinical responsabilities in the diagnostic work up and management of patients with cardiovascular diseases in the Cardiovascular Research Unit of the Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom. His supervising Consultant has been Professor Attilio Maseri MD, FRCP, Sir John McMichael Professor of Cardiovascular Medicine.
6 October 1988 - 25 September 1990. During this period he has been also working as research investigator, in the Medical Research Council, Cyclotron Unit, Hammersmith Hospital, under the supervision of Dr Terry Jones DSc. His research projects were also performed in conjunction with the Nuclear Medicine Section of the Department of Diagnostic Radiology, Hammersmith Hospital under the supervision of Professor J P Lavender, MB ChB FRCR FRCP.
1 October 1992 - 22 December 1994. Internal medical doctor in the Institute of Internal Medicine and Geriatrics, University of Catania, under the supervision of Prof. L. Motta. During this period he has been involved in research project and diagnostic work up and management of patients with cardiovascular diseases.
23 December 1994 – 5 December 1996. Registrar in the Institute of Cardiology, Ferrarotto Hospital, University of Catania, under the supervision of Prof. G. Giuffrida, full Professor of Cardiology.
27 May 1996 – 5 December 1996. Senior registrar appointee in the Institute of Cardiology, Ferrarotto Hospital, University of Catania, under the supervision of Prof. G. Giuffrida, full Professor of Cardiology.
6 December 1996 – 30 July 1999. Senior Registrar in the Institute of Cardiology, Ferrarotto Hospital, University of Catania, under the supervision of Prof. G. Giuffrida, full Professor of Cardiology.
January 1995 – October 1999. During this period he has been also working as research investigator, in the Institute of Radiology of the University of Catania, under the supervision of Prof. Salvatore Musumeci, full Professor of Nuclear Medicine.
From 31 Luglio 1999 to 30 November 2006. Senior Registrar, in the Institute of Cardiology, Ferrarotto Hospital, University of Catania; he was the Director of Diagnostic and Cardiovascular Interventional Laboratory, Clinical Division of Cardiology, Ferrarotto Hospital from the 15th December 2005.
From 1994 to 31 July 2011. During this period Prof. Galassi has performed more than 2696 invasive diagnostic angiographic procedure (diagnostic coronary angiogramm, angiographic arterial examination, endomyocardial byopsis), 2180 percutaneous coronary interventions (as first operator with and without the use of stents, complex angioplasty such as elective chronic total occlusion, bifurcation lesions, left main trunk stenosis, or acute myocardial infarction) and 26 implants of temporary pacemakers under the direction of Professor G. Giuffrida from 1994 to 2003 and Professor C. Tamburino in 2004 in the Diagnostic and Cardiovascular Interventional Laboratory at the Clinical Division of Cardiology, Ferrarotto Hospital, University of Catania, that he has directed since December 15th, 2005. Furthermore, he has taught and performed interventions for n° 203 days (95 in Italy e 203 abroad) treating a total of 570 patients.
From the 1st December 2006 – onwards. Associate Professor of Cardiovascular Medicine, Faculty of Medicine and Surgery, University of Catania, Department of Clinical and Experimental Medicine (former Department of Medical Sciences and Pediatrics).
From August 1st 2011 to April 6th 2016. University Medical Director at the Clinical Division of Cardiology, Cannizzaro Hospital. From September 6th 2011 to August 6th 2015. Director of Diagnostic and Cardiovascular Interventional Unit, Cannizzaro Hospital. During this period Prof. Galassi has carried out his diagnostic, interventional and didactic activities for a total of over 1574 procedures.
From 7 April 2016 – 30 June 2019. University Medical Director at the Unit of Cardiology, University Hospital Policlinico, Vittorio Emanuele, within the Vascular-Cardiothoracic and Transplant Department.
From November 1st 2016 to October 31st 2018. Sabbatical year art 17 DPR 382/80 as modified. During this period, interventional and didactic activities were carried out (live courses, lectures and international meetings) for a total of over 741 procedures of complex coronary lesions (common trunks and bifurcations) and chronic coronary occlusions.
From November 1st 2018 to January 1st, 2019. On duty at the Unit of Cardiology, University Hospital Policlinico, Vittorio Emanuele, within the Vascular-Cardiothoracic and Transplant Department.
From January 2nd 2019 to December 17th, 2019. Paid mobility for research activities at the Royal Brompton & Harefield NHS Foundation Trust, London, UK, with an agreement between the Hospital and the Department of Clinical & Experimental Meidcine of the University of Catania.
From July 1st 2019 – onwards. Full Professor of Cardiovascular Disease, Faculty of Medicine and Surgery, University of Palermo, Department of health Promotion mother and child care, Internal Medicine and medical SpecialtiEs, PROMISE, Policlinic Paolo Giaccone, Palermo.