Research by the Scottish Conservatives has shown some people are waiting up to nine months just to see a specialist after being referred by a GP.
Under Scottish Government targets, cardiology patients should wait no longer than 12 weeks for a new outpatient appointment.
However, it has now emerged that in the last three months alone, 1418 cases have breached this standard, according to the Freedom of Information data.
It means one in five cardiology patients are not being seen by a specialist on time.
Worse still, 846 people waited more than 16 weeks between April and June this year.
In NHS Ayrshire and Arran, 34.9 per cent of heart patients weren’t treated on time, with the longest wait 262 days.
In Grampian, 37.1 per cent missed the target, with a longest single wait of 224 days, while in Tayside it was 33.5 per cent missed and 276 days the longest wait.
It is the latest in a line of damning statistics suggesting the NHS is buckling under the strain of a lack of investment and poor forward planning.
Last week, Audit Scotland revealed a series of failings across Scotland’s hospitals, while the SNP narrowly avoided defeat in Holyrood on a motion blasting its record on health since 2007.
Scottish Conservative shadow health secretary Donald Cameron said:
“We know all too well the problems caused by heart disease across Scotland.
“Yet despite the warm words from the SNP, cardiology patients are waiting months to see a specialist.
“This is utterly unacceptable. It’s outrageous to think someone could be referred by a GP for a heart problem, then have to wait up to nine months to actually clap eyes on a specialist.
“With every week that goes by, we learn more about how badly the NHS has struggled under SNP stewardship.
“Key areas have been neglected, staffing levels have been allowed to slip, and ministers have paid no heed to the challenges brought by an ageing population.
“We need to see urgent action to turn these statistics around, and improve cardiology care right across the country.”