In honor of Heart Month in February, Sunnybrook Health Sciences Center in Canada conducted a live event showing a coronary artery bypass graft. They showed everything from what happened when the surgical team opened up the patient’s chest, to when doctors stopped his heart, to when they stitched him up.

The surgery was conducted to improve blood flow to the heart of the patient, named Lou, after it was slowed by plaque due to coronary artery disease, the hospital said on its website. If such a surgery were not completed, the disease could have led to pain or a heart attack.

(Image source: YouTube)

Image source: YouTube

Sunnybrook live tweeted the surgery and took video of the heart in the opened chest cavity.

Watch the stunning six-second footage of the heart beating (content warning: this footage might be considered graphic):

Lou's breastbone has been separated to expose the heart, while Dr. Dekel harvests an artery from the arm. #SBheart http://t.co/RczxERB47L
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital
Lou has been connected to the bypass or "heart-lung" machine, which keeps oxygenated blood pumping through his body. #SBheart
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital
While Lou's heart has stopped, the heart-lung machine will take in deoxygenated blood, oxygenate it and return it to his body. #SBheart
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital
It takes a whole team: in this pic, Lou's anesthesia care team, surgeon, fellow and perfusionist #SBheart http://t.co/805oxbgRJi
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital
Close-up of the radial artery harvested from the left arm. This will be used as one of two bypass grafts. #SBheart http://t.co/5PjNarvJYy
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital
Dr. Cohen + Dr. Dekel sew grafts into place. It's like creating a road detour around blocked arteries. #SBheart http://t.co/DTZ57xRI2r
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital
With the grafts complete, the heart has resumed beating. Dr. Cohen + team have inserted tubes in the chest to collect excess fluid. #SBheart
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital
Chest is closed using stainless steel wires, which brings bone back together. Bone heals in about 6 weeks #SBheart http://t.co/h16zNYaToc
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital
Dr. Dekel has finished closing up and stitching Lou's chest incision #SBheart http://t.co/BXaarNetP2
Sunnybrook Live Tweets and Takes Video of Heart Bypass Surgery
@Sunnybrook
Sunnybrook Hospital

And then here’s the moment where you can see the heart go from beating to stopped:

The patient, who was only identified by his first name and consented to the live tweeting of his surgery, is 57 years old and “looks forward to his recovery so he can get back to spending time with his family and return to his hobbies.”

For an even more detailed play-by-play, check out more of Sunnybrook’s Twitter stream.