How painkiller overdose can cause cardiac arrest

The death of pop music icon Michael Jackson from cardiac arrest on Thursday has raised a host of questions about what might have caused it.

It may take weeks before an autopsy can reveal the true circumstances that led the singer’s heart to stop.

One possible cause reported by celebrity website TMZ.com is that he was injected with the potent painkiller Demerol before he went into cardiac arrest.

Others speculate it was a combination of Demerol and Oxycontin, another powerful painkiller that is among the most commonly abused prescription drugs.

Here are some facts about cardiac arrest and both these drugs.

How could Demerol cause cardiac arrest?
Cardiac arrest occurs when the heart stops circulating blood. In 80 percent of cases, the cause is heart disease, but narcotic painkillers like Demerol can cause cardiac arrest.

Dr. Daniel Simon, chief of cardiology at University Hospitals Case Medical Centre in Cleveland, said if Jackson had been injected with too much Demerol, it might have caused him to stop breathing, a condition called respiratory arrest.

“The most likely scenario with Demerol would be that it caused a respiratory arrest because it takes away the drive to ventilate (breathe),” Simon said in a telephone interview.

He said low blood oxygen can trigger a deadly heart rhythm known as ventricular fibrillation in which the heart quivers, but does not circulate blood.

“Without CPR and a defibrillator, you have no chance,” Simon said.

Depresses system
ABC News has reported that Jackson was addicted to prescription painkillers, and may have used Demerol in combination with Oxycontin.

Cleveland Clinic cardiologist Dr. Bruce Lindsay, past president of the Heart Rhythm Society, said the two drugs in combination could cause respiratory arrest.

“As with any of these painkillers, if you get too much on board, it really depresses the central nervous system so the patient could lapse into a deep sleep or even a coma. And if their respiratory capacity was too depressed, they would just stop breathing,” Lindsay said.

“If they stop breathing, eventually of course the heart will go into cardiac arrest, but not because of some primary heart problem.

It is simply because the final mode of death is that the heart stops beating.”