AS WELL as minding their blood pressure and cholesterol levels, people with heart disease should keep an eye on their heart rate in order to avoid further heart problems, new research suggests. Dr Muiris HoustonMedical Correspondent in Munich reports.
The Congress of the European Society of Cardiology (ESC) in Munich was told yesterday that a person's heart rate was a powerful predictor of their risk of having a heart attack.
Patients with existing coronary artery disease and with a heart that is not pumping blood to its full capacity and who have a heart rate greater than 70 beats per minute are significantly more likely to die from heart disease or suffer a heart attack.
The "Beautiful" study of 11,000 people in 33 countries - including patients from Galway and Dublin - with known coronary artery disease found that those with a resting heart rate of more than 70 beats per minute had a 56 per cent increased risk of developing heart failure. The increased risk of having a heart attack was 46 per cent, while the risk of needing a further stent or a bypass was increased by a third.
One of the authors of the study, Dr Roberto Ferrari of the University of Ferrara, Italy, told doctors that "heart rate should be assessed as a prognostic marker and to guide the optimal medical treatment [of patients with coronary artery disease]".
Prof Gabriel Steg, of the Hospital Bichat-Claude Bernard, Paris, said the study was the first one to show that a high resting heart rate was an independent risk factor in coronary artery disease patients.
The researchers also reported that reducing a person's heart rate with the drug ivabradine significantly reduced the risk of hospitalisation with a heart attack by a third.
Interestingly, the patients studied were already receiving recommended drug treatment for cardiovascular disease: about 90 per cent of participants were taking aspirin, beta-blockers and another cardioprotective drug, angiotensin-converting enzyme (ACE) inhibitors. "The results of 'Beautiful' constitute a step further in the management of coronary patients with a heart rate above 70 beats per minute, because, for the first time it has been shown that pure heart rate reduction with ivabradine further reduces coronary events even in patients receiving the current optimal cardiovascular therapy," the authors said.
Although ivabradine reduces heart rate, it acts in a completely different way to beta-blockers, the drug traditionally used to slow the heart.
Ivabradine, which is already licensed to treat angina (heart pain), acts on a specific part of the heart's pacemaker called the sino-atrial node. This small area is located in the atrium, the upper chamber of the heart. The drug does not affect blood pressure or change the ability of heart muscle to function.
This major breakthrough, the subject of two research papers published online by The Lancet yesterday, means that the simple measurement of heart rate has become a key indicator of how a person with existing heart vessel blockages will progress in the years following a cardiac event.
Lead author Prof Kim Fox, of the Brompton Hospital, London, said coronary artery disease patients with a heart rate of more than 70 beats per minute "can now benefit from a treatment that will greatly reduce their chances of having another heart attack or needing further surgery".
Commenting on the results, Irish investigator Dr John Barton from Portiuncula Hospital in Ballinasloe, Co Galway, said: "Often a lot of investigations are performed in daily clinical practice but a simple heart rate measurement is overlooked. 'Beautiful' has confirmed the need to measure heart rate in all coronary artery disease patients and if the heart rate is more than 70 beats per minute, appropriate treatment should be considered."