A pair of videos making the rounds on YouTube show implantable cardiac defibrillators in action, after two patients experienced irregular heart rhythms and their ICDs kick in to restore their heartbeats (hat tip: Dr. Wes).
In the first clip, Danish physicist Henrik Svensmark suffers a cardiac event at the Copenhagen Climate Summit:
Here’s Dr. Wes to explain exactly what happened:
“Implantable cardiac defibrillators fire when the ventricular heart rates exceed a pre-determined heart rate that is sustained for a predetermined number of heart beats. It is unclear if his heart rate was elevated from a lower heart chamber (ventricular) arrhythmia (the most likely cause) or a racing upper chamber (atrial) heart rhythm abnormality that drove the lower chamber too fast.
“Dr. Svensmark’s heart rate was probably not fast enough to cause him to lose consciousness. Nonetheless, when the defibrillator fires, it delivers the equivalent of approximately 830 volts in a tenth of a second, causing the muscles of the chest, heart, vocal coards and diaphragm to contract forcefully, occassionally resulting in the ‘yelp’ heard at the just before the video ends.”
In the second video, 20-year-old Belgian footballer Anthony Van Loo undergoes a similar event:
Again, Dr. Wes explains:
“In this video, Van Loo is seen walking from the field and then collapsing at 7 seconds, his legs are seen twitching at 15 seconds as his automatic defibrillator fires to restore his heart rhythm to normal, and then by 21 seconds after the event he regains consciousness and sits up. According to some reports, Van Loo was not allowed to return to soccer unless he had an ICD implanted due to his known cardiac disorder.”
As Dr. Wes points out, neither event was a heart attack, despite their YouTube billing as such. “Despite all of the press out there, this is NOT a heart attack, but rather the result of a life-threatening heart rhythm disorder like ventricular fibrillation or ventricular tachycardia,” he writes.