Stroke of Unknown Cause Clinic

Revolutionizing stroke treatment in Ontario with St. Michael’s Hospital’s Stroke of Unknown Cause Clinic (SOCC) – our unique clinic provides timely, comprehensive care for patients with strokes of unknown cause. This innovative stroke care experience at the SOCC clinic brings together specialists from stroke neurology, thrombosis, and cardiology under one roof. The aim is to provide diagnosis and treatment of stroke patients who are struggling to find an answer as to why they had a stroke and what needs to be done.

While the traditional complex stroke clinic care model often involves multiple tests and consultations with different specialists — a process that can span months – this clinic allows for a shorter timeline totaling a single hour-long visit, fostering seamless physician collaboration and empowering patients with timely answers and comprehensive care. From selecting the best blood thinner, to cardiac procedures, to counseling on critical lifestyle decisions, Unity Health’s SOCC based at St. Michael’s creates personalized care plans for our patients.


Medical Director, Stroke Program, St. Michael’s Hospital
Assistant Professor of Medicine, University of Toronto

Dr. Atif Zafar obtained his Bachelor of Medicine, Bachelor of Surgery (MBBS) from Dow Medical College, after which he completed his residency at the University of Iowa Hospital and Clinics. He has also completed his Vascular Neurology Fellowship through the Cleveland Clinic, Ohio.

Upon completing his fellowship, Dr. Atif Zafar became an Assistant Professor, Stroke and Vascular Neurology at the University of New Mexico School of Medicine, before becoming the Chief of the Stroke Program at UHM School of Medicine.

Currently, Dr. Atif Zafar is an Assistant Professor of Medicine, Division of Neurology, at the University of Toronto. He is also the Medical Director of St. Michael’s Hospital Comprehensive Stroke Program.

Clinical interests and areas of expertise: Complex stroke cases, cerebral cavernous malformation, cerebrovascular diseases, fibromuscular dysplasia, vascular dementia, stroke recovery

Academic interests (research, teaching/education, quality improvement etc.): Personalized stroke algorithm, improving access to care, health equity and developing patient centered care programs.

Publications: Link

Department: Medicine

Division: Neurology

Clinics: Stroke of Unknown Cause

Languages: English, Urdu

Contact information:

Office: 416-360-4000

Clinical: 416-864-5056

Fax: 416-864-5712

Location: St. Michael’s Hospital

Staff Hematologist, St. Michael’s Hospital
Assistant Professor, University of Toronto

Dr. Eric Tseng completed his MD degree at the University of Toronto, followed by Core Internal Medicine and Adult Hematology training at the same institution. He then completed a thrombosis fellowship and was a Clinical Scholar at McMaster University and St. Joseph’s Healthcare Hamilton.

His academic interest is in medical education and he completed a masters in health professions education (MScCH-HPTE) from the Dalla Lana School of Public Health at the University of Toronto.

Dr. Tseng is actively involved in knowledge translation activities related to thrombosis medicine through the American Society of Hematology and Thrombosis Canada.

Clinical Interests and Areas of Expertise: Thrombosis, Iron Disorders, Immune Cytopenias, General Hematology

Academic Interests (Research, Teaching/Education, Quality Improvement etc.): Teaching and Education

Publications: Link

Department: Medicine

Division: Hematology

Clinics: General Hematology, Thrombosis, Stroke Of unknown Cause Clinic

Languages: English

Contact Information: 

Office: 416-864-5128

Clinical: 416-864-5128

Admin: 416-864-5128

Fax: 416-864-3055

Location: St. Michael’s Hospital

St. Michael’s Hospital
Assistant Professor of Cardiology, University of Toronto

Dr. Alnasser received his medical degree from King Saud University in Riyadh in 2004. He completed training in Internal Medicine at McMaster University and Fellowship in Cardiology, interventional Structural and Congenital Cardiology at The University of Toronto. He is a staff Interventional Cardiologist at St Michael’s Hospital.

Dr. Alnasser is the Site Director for the Cardiology Residency program at St. Michael’s Hospital and the Cardiac Lead at Li Ka Shing Knowledge Institute Simulation Lab. Dr. Alnasser codirects the Brain and Heart Innovative Clinic Centre and is the lead physician for the Stroke Of unknown Cause Clinic (SOCC).

Before joining St. Michael’s, Dr. Alnasser codirected the Structural Heart program at Health sciences North and and helped establish several programs in North Ontario including minimally invasive transcatheter aortic valve implantation, transcatheter atrial septal defect closures as well as ECMO (Extracorporeal Membrane Oxygenation) for patients with Cardiogenic Shock.

He had several publications in the field of Structural and Congenital Cardiology including analysis of the Ontario Ministry of Health data to understand the long-term outcomes after transcatheter atrial septal defect closure in comparison to the general population. Other work included comparisons of various transcatheter heart valves in the management of aortic valve disease and the safety of early hospital discharge after TransCatheter aortic valve implantation in North Ontario and rural areas.

Academic Interests (Research, Teaching/Education, Quality Improvement etc.): Stroke and congenital heart disease; health care delivery in rural areas.

Publications: Link

Department: Medicine

Division: Cardiology

Clinics: Stroke Of unknown Cause Clinic (SOCC), Structural Heart Clinic

Contact Information: Clinic: 416-864-5905

Fax: 416-864-5566

Admin: 416-864-5685

Location: St. Michael’s Hospital


St. Michael’s Hospital

30 Bond St.,
Toronto, ON
M5B 1W8
The main entrance is located near Queen St. East and Victoria St. The Bond St. entrance is not open to the public at this time.


(Dr. Alnasser’s general clinic line and fax)

Phone: 416-864-5905 

Fax: 416-864-5566

Health-care Providers

Referral form