February 18, 2021

Heart Month: Dr. Hayek Explains Heart & Brain Health

Dr. Salim Hayek, Medical Director of the Michigan Medicine Frankel Cardiovascular Center Clinics, details the links between heart and brain health. Dr. Hayek also describes the important research that he and Dr. Eva Feldman are conducting to understand how COVID-19 is impacting the brain, heart and other organs.

Dr. Salim Hayek

How is heart health and brain health correlated? 

“The brain and the heart are very closely linked. Brain and heart diseases have shared risk factors. For example, strokes and coronary artery disease both have high cholesterol, hypertension, smoking and stress as risk factors. The disease process that affects the blood vessels of the heart are very similar to the ones that are in the brain. That’s aside the functional link between the brain and the heart in which the brain and spine control the innervation of the heart. Any severe events that affect the brain, like high-stress situations or bleeding in the brain can lead to heart dysfunction in a phenomenon we call stress-induced cardiomyopathy. The link between the brain and the heart goes beyond the blood vessels. They’re linked functionally through the nervous system.”

How do protective recommendations for the heart – balanced diet, regular exercise and blood pressure control - also protect the brain?

“Given diseases of the nervous system and heart often share similar risk factors – that’s why we lump them together - cardiovascular and cerebrovascular diseases – vascular being the key common word here. They both have shared risk factors. Anything that affects the vasculature of the heart, and the rest of the body can also affect the vasculature of the brain. Specifically, I’m referring to blood pressure, to smoking and to high cholesterol. These are characteristics that are affected by lifestyle above anything else. A heart-healthy lifestyle is in essence a brain-healthy lifestyle. The measures that decrease the risk of stroke are the same as to decrease the risk of heart attack.”

 How do you and Dr. Feldman complement each other’s research?

“It’s an immense pleasure working with Dr. Feldman, not only because she’s an expert in neurology. She’s an expert in everything. She’s great at having a big picture view of problems. Although she’s an expert in neurology, she also has a very good understanding in all the different processes that affect the body. She is a mentor to me. I bring a very specific clinical expertise to her work, aside the cardiovascular aspect, I’m a risk prediction expert and a biomarker researcher. In that we both complement each other in more ways than one.”

Can you explain the current COVID-19 project you are working on with Dr. Feldman?

“Our main collaborative project right now relies on the understanding the sequelae of severe COVID-19 infection. We’re also looking at various aspects of how diabetes affects both the nervous system and the heart. The heart is heavily innervated and heart function is dependent on a healthy nervous system. Diabetes affects both the nervous system and the vasculature. We’re in the beginnings of working together for a better understanding the impact of diabetic neuropathy on cardiac function.”

In your research, how is COVID-19 impacting the heart? Is it impacting the nervous system?

“So far at the University of Michigan we’ve had over 2,000 patients who were hospitalized with COVID-19 who we’ve been following very closely during their hospitalization. While the incidence of cardiovascular injury is quite common in patients with severe COVID, often these patients who survive and are discharged we have so far not seen a very large burden of heart failure or major cardiovascular complication. We have seen quite a bit of patients who complain of palpitations and chest pain without evidence of myocardial injury. This is a process that we are really trying to understand and sort out. My personal hypothesis is that it actually has to do with the impact of COVID on nerves and the nervous system, more so than the heart muscle itself. It is common that we see these complaints in the absence of signs of severe cardiac dysfunction. As to the exact reason why we’re seeing these reports of fatigue, palpitations, sometimes chest pains, we’re trying to sort this out. It’s very possible that this may be linked to neurological type of dysfunction or impact on the nervous system.”

How do you study the potential long-term effects that COVID-19 has reportedly had on heart and brain function?

“We’ve seen these reports and met these patients who have brain fog and fatigue. One of the important questions that is unanswered is - are these patients who are predisposed to experience these effects, or are these patients who were completely fine before that, and then suddenly they developed these symptoms after COVID? And how long do these symptoms persist? These are all important questions that we’re trying to answer right now in our Michigan Medicine COVID-19 cohort in our multidisciplinary clinic research. There’s a lot that we don’t know and we’re trying to figure it out.”

What will your involvement be in the COVID-19 Multidisciplinary Clinic that will be opening at Michigan Medicine?

“I’ve been involved in its inception, its design and its management. I’ll also be involved as a provider seeing patients with COVID-19 and with the research. I’m involved in all aspects of the clinic.”