What is cardiac arrhythmia? Director Jean-Marc Vallée's cause of death revealed

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A final coroner's report has revealed new details including the cause of death of Oscar-nominated director and producer Jean-Marc Vallée.

Vallée, who was known for films like "Dallas Buyers Club" and the hit HBO series "Big Little Lies," was found dead at his cabin outside of Quebec City on Dec. 25, 2021. The 58-year-old Montreal-native was believed to have been preparing to entertain guests for the holidays when he died from what's now been determined as "a fatal arrhythmia secondary to severe coronary atherosclerosis."

According to Deadline, Vallée's death was particularly shocking since he abstained from alcohol and was "a fitness fanatic." A preliminary report received by the director's family on Dec. 31 stated that "Mr. Vallée’s death was not caused by the intervention of another party, a voluntary act, or a known disease."

"Testimonials of friendship, esteem and respect for our father and for his work are still coming from around the world," his sons Alex and Émile Vallée said in a statement following his passing. "We are sincerely grateful and we hope that his creativity will continue to serve as inspiration and guidance to the people in this industry that he was so passionate about."

Read on to learn more about cardiac arrhythmias, signs and symptoms, and how they can be prevented.

What is a cardiac arrhythmia?

A cardiac arrhythmia is an irregular heartbeat. If you have an arrhythmia, your heart may beat slower or faster than what is considered normal.

"A cardiac arrhythmia is serious because the condition can be silent, meaning you don't notice any symptoms or you associate your symptoms with something else," a representative from the University of Ottawa Heart Institute (UOHI) tells Yahoo Canada. "Oftentimes, doctors only spot the condition during a physical exam."

There are several conditions that might cause your heart to beat abnormally, and treatment depends on the cause. However, it can be normal to have a fast or slow heart rate. For example, the heart rate may slow down during sleep or increase while exercising.

"Generally, cardiac arrhythmias are grouped by the speed of the heart rate," the UOHI source, who asked to not be named, says. "A tachycardia arrhythmia is a fast heartbeat (resting heart rate is greater than 100 beats per minute), and a bradycardia arrhythmia is a slow heartbeat (resting heart rate is less than 60 beats per minute)."

"Cardiac arrhythmias may feel like a racing or fluttering heart and can be harmless. But some arrhythmias may be aggravating and life-threatening," they add.

What causes cardiac arrhythmias?

Cardiac arrhythmias occur when the electrical signals that coordinate heartbeats don't work properly. This causes the heart to beat too slow, too fast, or a combination of both.

"Arrhythmias can also be caused by high blood pressure, electrolyte imbalances, irritable heart tissue, injury from a heart attack, changes in the heart muscle or coronary atherosclerosis," the UOHI source continues.

Coronary atherosclerosis, the secondary cause of Vallée's passing, kills 70,000 Canadians each year, per the University of Ottawa. Aside from cancer, it is the second-leading cause of death.

The UOHI representative explains that "coronary atherosclerosis is triggered by plaque buildup in the the coronary arteries, which supply blood to the heart and the human body. Over time, the plaque build-up narrows arteries resulting in adverse health effects."

What are the signs and symptoms of cardiac arrhythmias?

Cardiac arrhythmias may not cause any symptoms or warning signs. However, a medical professional can diagnose an irregular heartbeat while performing diagnostic tests, taking a pulse, or listening to a patient's heart.

"Although symptoms can be silent, the signs of a cardiac arrhythmia include shortness of breath, chest pounding or discomfort, weakness or fatigue, a fluttering in the chest, and feeling dizzy or lightheaded," says the UOHI source. "Other common symptoms may include sweating, fainting and anxiety, which is why the condition can easily be mistaken for something else."

If you have symptoms of an arrhythmia, or if you feel like your heart is beating too quickly, too slowly, or is skipping a beat, you should make an appointment to see a doctor or a cardiologist.

Who is at risk of a cardiac arrhythmia?

There are a variety of factors that increase the risk of cardiac arrhythmias and irregular heartbeats. If you have certain medical conditions including coronary artery disease, congenital heart disease, thyroid disease, high blood pressure or sleep apnea, you may be more at risk of developing the condition.

"Excessive use of stimulants such as alcohol, caffeine, nicotine or drugs can also cause your heart to beat faster or slower than normal and may lead to the development of more serious arrhythmias or death due to ventricular fibrillation," explains the UOHI source.

How are cardiac arrhythmias treated?

Treatment can depend on the severity and type of the arrhythmia. Once identified, there are various treatment options including catheter or pacemaker procedures, medication and surgery to control or eliminate fast, slow or irregular heartbeats. These treatment options are usually very successful.

How can I prevent cardiac arrhythmias?

Implementing heart-healthy lifestyle changes can help prevent heart damage that can trigger certain cardiac arrhythmias. Examples include exercising regularly, getting adequate sleep, and eating a healthy diet that's low in salt and fats and rich in fruits, vegetables and whole grains.

"I would also recommend quitting smoking, reducing caffeine and alcohol intake, and monitoring blood pressure and cholesterol levels," explains the source.

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