tachycardia

It's known to cause tachycardia in some people, which is not something to be taken lightly.

Went a few days with little to no sleep, drank a bunch of huge energy drinks, and ended up in the hospital with tachycardia.

The withdrawal sucked--about 4 days of sweats, shaking, tachycardia, and a real hard time sleeping.

A defibrillator gives a large shock to the heart to knock it out of a dangerous rhythm such as ventricular tachycardia or ventricular fibrillation.

I think by "restart", he meant the useful shorthand of "restore a useful rhythm, restart the heart as a pump instead of a tasty snack", and only in the case where the heart was in ventricular fibrillation or tachycardia.

"I'm so practiced at having them, nobody standing around me is ever aware that I'm having a sudden bout of tachycardia and growing concerns that my heart is about to explode in my chest"Believe me, I recall that sensation, and I don't miss it.

This is a bit off topic, but according to wikipedia; "Adverse reactions to adrenaline include palpitations, tachycardia, arrhythmia, anxiety, headache, tremor, hypertension, and acute pulmonary edema.

It seems to me, as a curious non-medic, that at the root of heart disease is a state of persistent arousal, which is similar to stress -- high blood pressure, high blood sugars and fats, tachycardia, low immune, high inflammation, poor digestion, etc. All arguably useful if you are hunting prey or raiding the next village.