The study's findings show that there are two types of heart failure and that the outcome for patients depends on the nature of their disease.
The research, headed by Auckland University Associate Professor Rob Doughty, was presented today to the European Society of Cardiology Congress in Barcelona.
The study looked at data from major heart-failure research groups around the world and involving more than 45,000 patients.
Prof Doughty said disease affected about 2 percent of people worldwide and occurred when the heart could not generate sufficient blood flow.
"Most people experience heart failure because their heart muscle does not pump blood properly," he said.
"For these patients, the standard heart failure treatment, which is designed to improve pump function, can be very effective."
However, his research team found that about one in four patients had normal heart pump function.
Their heart failure was caused instead by stiffening of the heart muscle and they would not benefit from the standard treatments targeting heart pump function.
Prof Doughty said previous research suggested that all patients with heart failure had a similar outlook, regardless of whether their symptoms were due primarily to pump failure or stiff heart muscle.
"Because of this, doctors have assumed that all patients should be treated in the same way," he said.
"Our research has shown that this is not, in fact, correct."
Prof Doughty said the findings had important implications for patients, physicians and nurses.
"By gaining a better understanding of the underlying causes of the disease, we will eventually be able to develop more effective treatments that will improve patient health and survival, as well as reducing health care costs."
People with heart failure typically feel tired and short of breath, have swelling in their legs and are unable to cope with physical exertion.
Prof Doughty said around three in every 10 New Zealanders admitted to hospital with heart failure for the first time would die within 12 months.
"This rate is as high as for many different forms of cancer, but heart failure has often not been considered in this way," he said.
As well as having an increased risk of death, patients whose symptoms were not well managed had a reduced quality of life and returned repeatedly to their doctors and to hospital.
About 1.5 to 2 percent of the entire health care budget in New Zealand and overseas was estimated to be spent on patients with heart failure.
National Heart Foundation medical director Professor Norman Sharpe said the study's findings were highly relevant clinically.
They would lead to direct improvements in the care of patients with heart failure, which was a common but complex and difficult condition to manage.
Prof Sharpe said the work, which the foundation funded, would be incorporated in new treatment guidelines.
