High baseline resting heart rate is associated with a higher prevalence and severity of angina and heart attacks, CLARIFY registry confirms


Results from CLARIFY, the largest international registry ever carried out in stable coronary artery disease outpatients, show that despite the widespread use of beta-blockers, one third of coronary artery disease patients had a resting heart rate of 70 bpm, a rate that has previously been shown to be linked with higher prevalence and severity of angina and heart attacks. The CLARIFY results, representing more than 30,000 patients from 45 countries worldwide, were presented at the European Society of Cardiology Congress in Paris, France. 

The CLARIFY (Prospective observational longitudinal registry of patients with stable coronary artery disease) registry was designed to increase the understanding of coronary artery disease, including an assessment of the role that heart rate plays in the prognosis of coronary artery disease patients. It aims to improve disease management by identifying gaps between existing evidence and actual practice.

CLARIFY enrolled 33 649 patients worldwide between November 2009 and July 2010. The mean age of patients, 77.5% of whom were men, was 64plus or minus11 years. The average pulse heart rate was 68.3plus or minus10.6 bpm, while the ECG-derived heart rate was 67.2plus or minus11.5 bpm. Forty four per cent of the patients had a resting heart rate greater than or equal to 70 bpm. In addition, in adjusted analyses, heart rate >70 bpm was independently associated with a higher prevalence and severity of angina, and with more frequent evidence of ischaemia.

“We have known for some years that heart rate is a potentially important risk factor in coronary artery disease, but until now, there was relatively little information regarding heart rate among coronary artery disease patients outside of hospital,” said CLARIFY chairman Gabriel Steg from the Hopital Bichat in Paris, France. “For the first time, we can see that many patients with coronary artery disease have too high resting heart rate levels, and combined internal evidence from CLARIFY and external evidence from prior sources indicate that this is associated with worse symptoms and worse clinical outcomes. These findings suggest tighter control of baseline heart rate with heart-rate-lowering medications may benefit coronary artery disease patients by improving symptom control and outcomes.”

Aspirin and statins were taken by more than 90% of patients and beta-blockers by 75%, indicating widespread uptake of evidence-based medication for secondary prevention. “It is encouraging to see that the majority of coronary artery disease patients receive treatments in line with management guidelines,” said Steg. “The results presented are just the beginning, CLARIFY has a prospective five-year follow-up planned and every year we will gather important information.”

The CLARIFY registry is funded by an educational grant from Servier. Data is being collected and analysed at the Robertson Centre for Biostatistics in Glasgow, UK, under the guidance of Ian Ford.