Sherry Beattie says her heartbeat often feels "like a washing machine that's off-balance when it's in the spin cycle."

She discovered she had atrial fibrillation — an irregular heartbeat, or arrhythmia — after suffering a stroke at age 58.

Her condition is partly controlled by medication. But Beattie, 61, suffers from fatigue and shortness of breath if she goes up stairs or tries to walk too fast.

After waiting for almost a year, Beattie, who lives in Erinsville, Ont., finally got a call saying she was scheduled for a cardiac ablation, a procedure to fix her arrhythmia, at the nearby Kingston General Hospital at the end of March.

But within days, it was cancelled as hospitals stopped all but the most urgent surgeries to free up resources for an anticipated influx of COVID-19 cases.

Meanwhile, her husband, Jim Beattie, 64, had suffered a heart attack in February and got his triple bypass surgery days before the restrictions came into place in March.

"It was just in under the line," he said.

Sherry Beattie's long-awaited cardiac ablation to fix her irregular heartbeat was scheduled for March 31, but cancelled due to the COVID-19 pandemic. Her husband Jim had a triple bypass earlier in March, just before coronavirus restrictions took effect at their hospital in Kingston, Ont. (Submitted by Sherry and Jim Beattie)

CBC News estimates that close to 100,000 patients across Canada have had their surgical procedures delayed due to COVID-19.

That estimate is based on data provided by the provincial and territorial health ministries, cross-checked with benchmark data from the Canadian Institute for Health Information (CIHI) on the number of procedures performed in previous years, when surgeries were at normal volumes.

In the dramatically scaled-back operating room activity amid the coronavirus pandemic, hospitals across Canada are continuing to perform surgeries on patients who are at high risk of death or disability if they aren't treated within days or weeks — a category that includes the most urgent cancer and cardiovascular cases.

But there are still thousands of patients with heart disease and cancer who have been assessed as less urgent whose procedures have been delayed. Both the Canadian Cancer Society and the Heart and Stroke Foundation have seen an increase in people turning to their online resources, including peer support.

Between 15,000 and 20,000 Canadians have likely had their cardiac procedures delayed due to COVID-19, according to an estimate by the Canadian Cardiovascular Society.

And according to Ontario's Ministry of Health, cancer surgeries were down by about 40 per cent between March 15 and April 12 compared to the same period last year. Assuming the demand for cancer treatment hasn't declined since last year, that translates to an estimated 1,700 patients whose cancer surgeries were postponed in Ontario alone — with the numbers continuing to rise as time goes on.

The pandemic has put the health-care system in an "impossible situation," said Andrea Seale, CEO of the Canadian Cancer Society. Patients whose procedures have been delayed are experiencing "a tremendous amount of anxiety," she said.

Although the most urgent cancer surgeries have continued through the COVID-19 pandemic, many others have been postponed, causing 'tremendous' anxiety for patients, says Andrea Seale, CEO of the Canadian Cancer Society. (Canadian Cancer Society)

"If you're going through cancer, your life has already been turned upside down and then this just adds to it," she said. "And we know that cancer is not stopping through the pandemic."

And there are thousands of other surgical procedures — including high volumes of cataract surgeries and hip and knee replacements — that have also been cancelled. The conditions requiring these procedures may not be life-threatening but can put patients at risk of vision loss, and cause extreme pain and deterioration in quality of life.

Specialists and their teams are staying in touch with many patients who are waiting. They try to reassure them they haven't been forgotten and monitor those whose conditions are at risk of deteriorating, said Dr. Shaf Keshavjee, surgeon-in-chief for University Health Network in Toronto. The network includes three surgical hospitals: Toronto General, Toronto Western and Princess Margaret (devoted to cancer treatment).

"The surgeons have been most worried," Keshavjee said. "They're just seeing these waiting lists growing, and anxious patients are phoning back and worrying."

How will surgeries ramp back up?

As the COVID-19 infection curve appears to move toward flattening in parts of Canada, many hospitals are starting to think about how to begin catching up on the enormous surgical backlog. But with the possibility of an increase in COVID-19 cases that could drain hospital resources still looming, they'll have to proceed with extreme caution, health officials say.

Surgeries across the country will slowly resume using a triage system, health ministries and doctors say, starting with the most urgent cases.

"Nobody's surgery is unimportant. It's just a matter of who ... is time-sensitive," Keshavjee said. "Things like cancer surgery, cardiac surgery, transplants and other time-sensitive surgeries will have to be prioritized.

"And we'll also have to, somehow, gradually increase our capacity to catch up in the backlog and continue to deal with new patients coming in."

Flattening the COVID-19 infection curve, securing funding to pay for overtime, and finding a consistent supply of personal protective equipment and COVID-19 tests for every patient are all requirements for surgeries to ramp up again, says Dr. Shaf Keshavjee, surgeon-in-chief at University Health Network in Toronto. (Submitted/University Health Network)

This week, University Health Network in Toronto has started to slightly increase the number of urgent cancer surgeries and transplants it is performing.

If it can continue to ramp up surgical volumes, Keshavjee hopes to be caught up on "time-sensitive" surgeries by the fall.

It's not clear how long it will take to catch up on other surgeries. It will depend on when procedures get back to a normal pace, as the backlog grows the more time passes, experts say.

Three key factors must be in place before a surgical ramp-up can proceed, Keshavjee said:

Government funding to pay for surgical overtime, including running evenings and weekends.

Enough COVID-19 testing kits for every patient to check if they are infected before undertaking surgery.

A reliable supply of personal protective equipment (PPE) for surgical staff as well as the rest of the hospital.

As surgical teams try to catch up, it's also essential to guard against staff burnout, said Dr. Andrew Krahn, a Vancouver cardiologist and president of the Canadian Cardiovascular Society.

"You don't want your operation [done] by a group of people that are tired and overworked and not sleeping well," he said. "So you have to find the right balance for what we can do."

Another critical factor to get surgeries moving again, experts agree, will depend on whether Canadians continue to follow public health guidelines, including physical distancing, frequent and thorough handwashing and staying home whenever possible — because if COVID-19 cases rise, surgeries will have to be quickly halted again.

"The faster that we can get through the pandemic, the faster that the health-care system can be back to its normal state," said Seale of the Canadian Cancer Society.

"It really will save lives."