A new Lancet Series explores the latest developments in the diagnosis, treatment and biology of cardiac arrhythmias, ahead of the American Heart Association’s annual meeting taking place this year on Nov 3–7 in Los Angeles, CA, USA.
Arrhythmias – problems with the heartbeat’s rate or rhythm, where the heart beats too quickly, too slowly, or with an irregular rhythm – are thought to affect over one million people in the UK, and are one of the top 10 reasons why people go to hospital*. Arrhythmias can disrupt the heart’s ability to pump enough blood to the body, resulting in a lack of blood flow which can damage the brain, heart, and other organs.
In a podcast to accompany the Series, Dr Andrew Grace at Papworth Hospital and Cambridge University, UK, says: “The current landscape in arrhythmia management would be unrecognisable to practitioners twenty years ago. We’ve made massive strides, but there are still gaps, [for example], drug treatment remains an issue; the drugs are variably effective, with many side-effects. In relation to atrial fibrillation, my personal view is that much of that is due to metabolic factors, and with increasing obesity in the population, that’s going to be something of a problem.” A Profile of Dr Grace is also published as part of the Series.
In the first Series paper, Systems biology and cardiac arrhythmias, Dr Grace and Dan Roden at Vanderbilt University in Nashville, USA, point out that during the past few years, the development of effective, empirical technologies for treatment of cardiac arrhythmias has exceeded the pace at which detailed knowledge of the underlying biology has accumulated. As a result, although some clinical arrhythmias can be cured with techniques such as catheter ablation, drug treatment and prediction of the risk of sudden death remain fairly primitive. Their paper outlines the present state of the biology behind arrhythmias, and highlights the potential for refined diagnosis, risk prediction and targeted treatment decisions that further understanding could offer.
The second Series paper, Catheter ablation of atrial arrhythmias: state of the art, provides an overview of catheter ablation, the leading treatment for some common types of arrhythmia. Catheter ablation consists of inserting thin, flexible tubes (catheters) into the heart (using a "key-hole" approach via the veins), in order to accurately target (ablate) the damaged part of the heart which is causing the abnormal heart rhythm. For many atrial arrhythmias the mechanism has been clearly defined and catheter ablation results in excellent long term outcomes. Further research is needed into the mechanisms underlying atrial fibrillation, and the authors – led by Professor Jonathan Kalman at the University of Melbourne, Australia – provide a comprehensive overview of the current state of the art in the area, as well as outlining future directions the field might take.
In the third Series paper, Ventricular arrhythmias and sudden cardiac death, a group of authors led by Dr Roy John and Professor William Stevenson at Brigham and Women’s Hospital in Boston, USA, highlight the importance of recognizing the different types of ventricular arrhythmias, and their association with sudden cardiac death in patients with heart disease. Implantable cardiac defibrillator devices (ICDs) reduce the number of deaths in people at risk for sudden death, and although anti-arrhythmic drugs and catheter ablation may not prevent sudden death, they are successful in reducing the arrhythmias that cause symptoms.
A Comment accompanying the Series by Dr John Camm at St George’s University of London, UK, suggests that new drug development, targeted ablation, and improved prediction of those at risk of sudden death are ripe for future research. A Lancet Editorial accompanying the Series concludes that: “With the expected rapid advances in understanding, and further translation of molecular evidence to the clinic, better treatment of cardiac arrhythmias and higher rates of prevention of sudden cardiac death are likely in the not too distant future.”
* Reference: NHS Choices, ‘Heart Rhythm Problems’ http://www.nhs.uk/Livewell/Healthyhearts/Pages/Arrhythmias.aspx [accessed October 19, 2012]