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Meet Dr. RJ Cusimano, a heart surgeon on a global mission

September 25, 2026   ●  
Dr. Robert James (RJ) Cusimano, UHN cardiac surgeon at the Peter Munk Cardiac Centre in an operating room with his surgical blue scrubs and PPE on.
Dr. Robert James (RJ) Cusimano, UHN cardiac surgeon at the Peter Munk Cardiac Centre.

World Heart Day Spotlight: world-renowned Toronto cardiac surgeon treating Canada’s rarest and most complex heart conditions while training the next generation of surgeons

For nearly two decades, something was growing inside Maria Loschiavo’s heart, undetected – until, just after her eighteenth birthday, it very nearly stopped it. She needed a surgeon willing to attempt one of the rarest operations in cardiac medicine: remove a cardiac fibroma, a benign mass of scar tissue that had likely been there since infancy.

UHN’s Dr. Robert James (RJ) Cusimano, a cardiac surgeon at the Peter Munk Cardiac Centre, Toronto General Hospital, was that surgeon – one of only a handful in the world able to remove growths this complex and rare.

Maria Loschiavo at her graduation wearing her blue robe and empty ceremony chairs in the background.
Maria Loschiavo at her graduation. (Photo courtesy of Maria Loschiavo)

High stakes & highly specialized: a rare heart surgery

Growths like the one in Maria’s case are seldom operated on, even by experienced heart surgeons, because of the uncertainty involved: cut away too much, and there may not be enough healthy heart tissue left to sustain life.

Using detailed computed tomography (CT) and MRI mapping done ahead of time, Dr. Cusimano is able to work around a growth without damaging nearby heart structures, often avoiding a second, much bigger operation. Operations like this can take several hours, with most patients home within a week, and a full return to normal life in the months that follow.

Dr. Robert James (RJ) Cusimano holding a model of a heart while in his office.
Dr. Robert James (RJ) Cusimano holding a model of a heart while in his office.

Building the only map of a disease too rare to study alone

Because these cases are so uncommon – no single country’s data is enough to guide treatment. The largest study of its kind covers only about 400 cases over 10 to 15 years.

To close that gap, Dr. Cusimano conceived INTERACT – the INTernational Registry to Assess Cardiac Tumours – with regional leads around the world:

● Russia, China and India
● Africa and Europe
● North America, South America and Australia

Cardiac tumours are so rare that we can’t get very much information from one country, from one surgeon. We have to get the whole world together.”

– Dr. RJ Cusimano

Training surgeons globally

A registry can pool the data, but treating patients takes hands-on skill – so Dr. Cusimano teaches it directly. Alongside his cardiac surgery caseload at Toronto General Hospital, he has taught and consulted with surgeons worldwide, often training local teams through one-on-one sessions and country-wide rounds. During his travels, Dr. Cusimano shares surgical expertise with local medical teams to successfully tackle cases that were previously thought to be “inoperable”, delivering lasting benefits to patients and families.

In 2016, he founded the Toronto Cardiac Tumour Conference. This free, donor-funded online resource with archived past lectures – brings international experts together each year to teach about the disease. The use of archived online lectures was a deliberate choice over a costly textbook, keeping the knowledge open to any surgeon, anywhere and anytime.

How philanthropy makes it possible

● Funds the travel and teaching that turns local expertise into global reach
● Powers INTERACT, the registry pooling rare-case data from every continent
● Keeps the Toronto Cardiac Tumour Conference free and open to any surgeon who needs it

None of this is possible on a global scale unless we have donors – whether it’s $5 or $5 million, every penny counts.”

– Dr. RJ Cusimano

A split image of the Peter Munk Cardiac Centre entrance and a reflection of an add of a heart outside of the entrance at Toronto General Hospital.
UHN’s Peter Munk Cardiac Centre at Toronto General Hospital.

A centre for the rarest cases

The Peter Munk Cardiac Centre is the premier cardiac centre in Canada. With more than 163,000 patient visits annually, the centre delivers innovative and compassionate care to patients, treating even the most complex cases of heart and vascular disease. From heart transplant to mechanical heart devices to surgery found almost nowhere else in Canada, it’s where patients go when they need answers – and donor support is what makes that possible.

For Dr. Cusimano’s patients – and for the surgeons he continues to train – that combination of expertise and support is what turns a rare diagnosis into a second chance.

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