Getting to the heart of the matter

It is estimated that heart attack survivors are four more times more likely to die suddenly from cardiac arrest, even if they receive good follow-up treatment. 

Researchers know about 10 per cent of heart attack survivors are left with pump dysfunction caused by scar tissue. The more severe the damage, the higher the risk of cardiac arrest, which is estimated to cause half of the deaths from heart disease in North America. 

Pump function often improves within the six months following a heart attack, but if it doesn’t— and the damage is severe enough— patients may need an implanted cardiac defibrillator to identify and treat the heart rhythms that cause cardiac arrest. 

Physicians recommend patients have a follow up echocardiogram, or ‘echo’, a special ultrasound test that measures heart function, three to six months after a heart attack to assess their risk of cardiac arrest, but researchers have found that doesn’t always occur.  

“The problem is, many patients aren’t examined at the six-month mark,” says Dr. Stephen Wilton, MD, a cardiologist and researcher at the Libin Cardiovascular Institute. “In fact, 50 per cent of patients don’t get follow up echocardiograms, increasing their risk of cardiac arrest.” 

Investigators don’t know why patients don’t follow up or whether the story is similar across Canada. In fact, there is even a gap in the knowledge of how many people are at risk of cardiac arrest. 
But researchers at the Institute are hoping to change that with phase one of the Acute Myocardial Infarction Quality Assurance (AMIQA) project. 

Led by Wilton, the study is following patients who have some degree of heart pump dysfunction after a recent heart attack. In addition to tracking the number of these patients who have an echo, the study asks patients, their doctors, and health system officials to complete a survey so investigators can better understand why some patients may not be getting the tests and treatment they need. 

 “We want to find out how often the ejection fraction [which measures heart function] is being checked around the country,” says Wilton. “We also want to know if isn’t happening, why not.” 

Wilton explains there are a number of barriers for patients, including long waiting lists for echocardiograms in some areas, difficulty obtaining follow-up appointments with cardiologists and possible gaps in knowledge for primary care providers.  

He adds the specific knowledge being gained from the data collected in phase one is critical in the project’s long term objective of reducing the number of heart attack survivors dying from cardiac arrest in Canada. 
He is excited that investigators will have their answers soon. Phase one, began in 2017 and has enrolled more than 500 heart attack survivors from 15 centres across Canada. Researcher hope to conclude the project in the spring of 2020.  

Wilton said the next phase will be focused on developing strategies to improve patient care. He is optimistic about the results, citing a previous smaller-scale study in Calgary that was instrumental in increasing the number of follow-up exams by 25 per cent. 

“The results of this project should show us the extent of this problem around the country, and hopefully will point to some simple, yet effective, tweaks to the process of care that will lead to better uptake of follow-up echo imaging in patients at risk of cardiac arrest," says Wilton. 

AMIQA is funded by the Cardiac Arrhythmia Network of Canada NCE, with additional financial support from the Libin Cardiovascular Institute, Medtronic Canada, Boston Scientific and Abbott. 

To learn more about this exciting research project, or to take part, visit www.ucalgary.ca/research/participate/study/13979/acute-myocardial-infarction-quality-assurance-canada-phase-1.