This large, important study represents one of the first that convincingly demonstrates that reversal of left ventricular hypertrophy results in a clinical benefit

Professor Gregory Yip, Birmingham City Hospital

This in turn hampers its efforts to push blood around the body, which may increase the chance of a heart attack.

ACE inhibitors work by expanding blood vessels and decreasing the pressure the blood needs to be pumped at to travel around the body.

It is already prescribed to many patients with high blood pressure, and also more broadly to those at risk of heart attack or stroke.

The "Hope" trial looked at 9,500 patients, who were either given ramipril, an ACE inhibitor, in addition to their standard therapy, or a placebo or vitamin E pill.

Earlier results from the study suggested that ramipril reduced the risk of cardiovascular deaths overall by a quarter.

The risk of heart attack fell by a fifth.

Heart muscle recovering

However, the latest analysis found that in more than nine out of ten ramipril patients, left ventricular hypertrophy either did not develop, or if present, regressed gradually.

This regression slightly reduced the chance of a stroke or heart attack, and more noticeably reduced the risk of getting congestive heart failure.

The study was carried out by Professor James Mathew, and colleagues at the University of Iowa College of Medicine - he called for patients to be tested for the heart muscle thickening using an electrocardiograph (ECG) test.

He said: "Until now, no agent has been shown to lower risk by causing a regression of left ventricular hypertrophy.

ACE inhibitors are currently underprescribed and often used in inadequate doses

Dr John Kennedy, Glasgow Nuffield Hospital

"We think we can now reduce the risk of cardiovascular events and death by regression of left ventricular hypertrophy using ECG markers."

Professor Gregory Lip, from Birmingham City Hospital, agreed: "This large, important study represents one of the first that convincingly demonstrates that reversal of left ventricular hypertrophy results in a clinical benefit, in a population at high risk of heart conditions.

"Speculation now arises on the mechanisms by which this occurs - they may lead to a greater understanding of how heart disease develops."

Dr John Kennedy, a cardiologist from Glasgow Nuffield Hospital, said that GPs should now be following advice to prescribe ACE inhibitors to all patients at risk from heart disease and stroke.

He said: "ACE inhibitors are currently underprescribed and often used in inadequate doses. GPs are in a prime position to change this."