Patients could be diagnosed and treated for heart disease sooner as more tests now need to be carried out within an eight week waiting time target.
Cardiovascular (heart and circulatory) disease is the biggest killer in Wales, with more than 9,000 deaths each year.
Currently, only those waiting for stress tests and an echocardiogram have to be seen within eight weeks.
But a review found those needing other tests such as blood pressure monitoring need to be seen and treated sooner.
There are about 375,000 people living with the condition in Wales - 4% of the population - according to the Welsh Government's Annual Statement of Progress on Heart Disease report.
From 1 April, eight more tests for patients with suspected heart disease will be added to the waiting time target.
Heart disease is caused when the coronary arteries become narrow because of a gradual build up of fatty materials.
This can mean not enough oxygen-rich blood gets through and can lead to a heart attack.
The new tests were "shadow reported" between April 2017 and December 2017 and during that period, numbers waiting more than eight weeks reduced from 33% to 17%.
Health Secretary Vaughan Gething said the move means "potentially very ill patients" will be diagnosed and treated sooner.
Dr Jonathan Goodfellow, president of the Welsh Cardiovascular Society, said: "People suffering with symptoms of heart disease need access to quick and effective diagnosis and treatment.
"Providing appropriate imaging and diagnostics, in local settings, allows patients to receive the minimum investigation necessary to get an accurate diagnosis."