By Aisha Dow
One in three younger Victorians who died suddenly from cardiac arrest used illegal drugs before their deaths, according to the findings of a new Australian study, which experts say highlights the underrecognised effect some illicit drugs can have on the heart.
There has been increasing evidence of a link between using street drugs – such as cocaine and methamphetamine, also known as ice – and premature heart complications and death.
Melbourne cardiologist Elizabeth Paratz is concerned that younger Victorians who use illicit drugs are overrepresented in sudden cardiac deaths.Credit: Chris Hopkins
“Over the last decade, or maybe even a little more, we’ve seen a substantial number of young people using methamphetamines with severe heart failure, to the point that they would require transplant or [they died suddenly],” said Dr Elizabeth Paratz, the study’s lead investigator and a cardiologist at the Baker Heart and Diabetes Institute.
The research examined the deaths of 523 Victorians aged 18 to 50 who had a toxicological assessment performed after they died of a cardiac arrest outside a hospital between April 2019 and April 2021. It found 32.5 per cent of these people either returned a positive toxicology result for illicit drugs (138 patients) or reported regular drug use (32 patients).
This rate of illicit drug use was significantly higher than is currently estimated in the general population. It is thought that about 19 per cent of all Australians aged 14 to 49 have used an illicit drug in the past 12 months.
While the authors wrote that it was possible that substance abuse was underestimated among younger Australians, the findings were also “consistent with the hypothesis that illicit drugs may exert acute effects on the cardiovascular system”.
“We do know that some illicit drugs are very harmful for the heart,” Paratz said. “In a way, it’s not surprising to see them over-represented amongst the sudden cardiac death cohort. But the degree to which they seem to be over-represented is quite surprising.”
There are many lifestyle factors that can contribute to heart problems. They include a poor diet, lack of exercise and legal drugs, including tobacco. But a number of experts said that the link between illegal drugs and cardiac arrests had been underrecognised.
The director of cardiology at St Vincent’s Hospital Melbourne, Associate Professor Andrew MacIsaac, who works alongside Paratz, said that in the past decade, illicit drugs had been increasingly recognised as the potential cause of unexplained heart attacks or chest pain, partly because of research conducted in Melbourne.
The American Heart Association’s diagnostic guideline now says it is reasonable to consider cocaine and methamphetamine as a possible cause of chest pain.
MacIsaac said he had seen patients who had heart failure due to long-term drug addiction, as well as patients who had cardiac incidents due to more casual drug use.
“Stimulant drugs such as amphetamines and cocaine increase blood pressure and heart rate, and also cause blood vessels to spasm. We believe that this has a very deleterious effect on people’s hearts when they use it, often, and can lead to a heart attack or can, in fact, permanently damage their hearts.”
The Victorians included in the study who died of sudden cardiac arrest after using illicit drugs were mostly likely to have cannabis in their system (106 cases), followed by amphetamine-type substances (83), heroin (36) and cocaine (16).
They were more likely to be men, smoke and drink alcohol regularly, and have a psychiatric diagnosis, compared to those who died without a history of illicit drug use. Many were using multiple legal and illegal drugs, and died while sleeping or sedentary.
The study didn’t include overdoses (162 overdose deaths were excluded), but examined cases where the illicit drug use was initially thought to be incidental.
Sudden cardiac deaths are generally defined by the World Health Organisation as an unexpected death that occurred within one hour of symptom onset or in a patient found dead within 24 hours of having been last observed alive and symptom free.
John Ryan, the chief executive of drug policy organisation, the Penington Institute, said despite the growing recognition among experts of the link between particular types of illicit drugs and heart damage, many people would feel uncomfortable openly discussing their drug use with a doctor.
“We’ve all heard of the doctor’s rule of thumb which is … whatever alcohol level the patient admits to this, double it to try and get an accurate reading. I think that’s even more challenging in the illicit space.”
Ryan said governments needed to step up with information campaigns.
“One of the issues that people really struggle with is identifying the signs of addiction and, and preventing transition from occasional use, which is pretty normal for young people … but it’s not normal to become dependent,” he said.
“We should be informing the community about that, in order to prevent addiction.
“I think we should also be more nuanced in the way that we treat different drugs. So you know, for example, cannabis is much less dangerous than methamphetamine... We’ve got to have those honest conversations.”
Paratz said asking about illicit drug use should be part of forming every patient’s medical history.
“I think particularly for methamphetamines, there can be a bit of a perception that it is a bit of a party drug and relatively clean. That’s absolutely not the case.
“You can cause long-term heart damage. And the tragedy is if you’re taking methamphetamine, usually you won’t get a transplant, because drug use is a contraindication.”
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