He was lucky. The ambulance that responded to his emergency in Minchinbury was one of hundreds in Sydney fitted with a system called ETAMI, or early triage for acute myocardial infarction.
It allows patients to be taken directly to one of two major hospitals, bypassing all smaller facilities, and getting vital treatment more than an hour earlier, saving lives and limiting damage to the heart muscle.
But more than 70 per cent of Sydneysiders are missing out because the NSW Ambulance Service has instructed most of its staff not to use ETAMI.
It believes 12-lead electrocardiogram (ECG) machines, used to diagnose patients, should be operated only by highly trained paramedics and that junior staff should not be required to manage cardiac arrest patients for the additional time it takes to transport them to one of the major hospitals.
The instructions have angered cardiologists. "We know that the quicker a person is treated, the higher their chance of survival," the director of cardiac services at Westmead Hospital, Pramesh Kovoor, said.
"But not everyone who calls an ambulance will get the same treatment and that's unfortunate because I don't believe it requires a paramedic to operate it."
For an ETAMI trial carried out between 2004 and 2007, 20 ambulances were fitted with 12-lead ECG machines capable of sending results by mobile phone to the emergency departments at Westmead or Royal North Shore hospitals.
The study, in the European Heart Journal , found about 1500 patients were delivered directly to Westmead's coronary care unit during that time, with 73 per cent on the operating table within 60 minutes and 66 per cent having angioplasty within 90 minutes, compared with 2 per cent of people taken to community hospitals.
A spokeswoman for NSW Health said the results of the trial were still being analysed and the NSW Ambulance Service would issue a statement on the matter within weeks.
For Mr Plant, 58, from Sadleir, in Sydney's south-west, the quick treatment meant only five days in hospital and a second chance at life.