The investigation, published in the British Medical Journal, consisted of data taken from more than 800,000 men and women who suffered heart attacks over the last decade.
Researchers believe the figures can be attributed to a combination of better preventative measures and improvements to the NHS.
Over half of the decline was a result of a decline in the number of heart attacks, and just under half was a decline in deaths after a heart attack.
The researchers have said that deeper investigations are needed in order to gain a better understanding of why the number of heat attack deaths has fallen, and what specific treatments or preventative measures can be attributed to the fall.
Professor Peter Weissberg, medical director at the BHF, said: “This impressive fall in death rates is...