Sanofi-Aventis's new heart rhythm drug Multaq should be considered as a first-line treatment option for patients with atrial fibrillation, a common arrhythmia, according to medical guidelines released on Sunday.

The recommendation from the European Society of Cardiology (ESC) is a fillip for a drug that has got off to a slow start commercially.

Multaq, or dronedarone, was designed as an improvement on the older drug amiodarone. It has a safer profile than the older medicine but has suffered from sluggish sales in the United States and Europe because studies suggest it is less effective.

The latest version of the ESC's guidelines on atrial fibrillation (AF) now includes Multaq, on the basis that it makes sense to choose a treatment that is safer, even though it may be less effective.

In view of the better safety and potential outcome benefit, dronedarone may be preferable as the first antiarrhythmic option, according to the guidelines, which were released at the ESC annual congress in Stockholm.

The new guidelines also include, for the first time, a statement on the importance of reducing hospitalizations in patients with atrial fibrillation -- something Multaq has been shown to do in a pivotal clinical trial.

The recently launched drug is not recommended for patients with serious heart failure.

Sanofi-Aventis is pleased with this first-line recommendation for Multaq in the AF guidelines which recognizes the extensive clinical development for the product as well as the innovative outcome of reducing cardiovascular hospitalization, said Marc Cluzel, the firm's head of R&D.

Multaq was approved in the United States in July 2009 and won approval from European medicines regulators last September. It is viewed as a key growth driver for Sanofi to see it through the years when patents expire on blockbusters like cancer treatment Taxotere and blood thinner Plavix.

The medicine is currently forecast to sell $1.5 billion a year by 2014, according to consensus analyst forecasts compiled by Thomson Reuters.

Atrial fibrillation is an abnormal heart rhythm in which the upper chambers of the heart beat in an uncoordinated manner. which can cause palpitations, shortness of breath and fatigue and raise the risk of more serious heart problems.

More and more people are suffering from the disease due to an increasingly aging population.