Drug holds promise for steady heartbeat: study

A study co-headed by UBC's dean of medicine, Dr. John Cairns, is offering new hope for people who suffer from abnormal heart rhythms (arrhythmias) in the years following a heart attack.

Published in the March 8 edition of the British medical journal The Lancet, the study demonstrates the safety and effectiveness of the antiarrhythmic drug amiodarone.

The results are good news for the 50,000 Canadians who survive heart attacks each year. Up to 20 per cent of these survivors develop ventricular arrhythmias and will be three to four times more likely to die in the following two years than heart attack survivors who do not develop arrhythmias.

Arrhythmias are one of the most commmon causes of cardiovascular disease-related death in Western society and are one of medicine's most difficult and dangerous conditions to treat.

The Canadian Amiodarone Infraction Arrhythmia Trial (CAMIAT) showed that amiodarone reduces the occurrence of fatal or near-fatal arrhythmias by nearly 50 per cent in the two-year period following a heart attack.

"The CAMIAT study provides us with very good evidence that amiodarone reduces fatal or near-fatal arrhythmias in this population of heart attack survivors," said Cairns, a cardiologist who headed the project with former colleagues at McMaster University. "Of particular importance, the CAMIAT study reassures cardiologists that amiodarone is considered safe in appropriately selected patients."

Amiodarone is the first antiarrhythmic drug to demonstrate overall protection from fatal or near-fatal arrhythmias. Previous studies were terminated prematurely when it was discovered that the drugs used actually increased the risk of death in heart attack survivors.

"Probably one of the greatest uncertainties in current clinical practice is the role of drug therapy in the management of serious cardiac arrhythmias. The results of the CAMIAT and EMIAT (a parallel European study) are very exciting and should make a difference in the way we manage those persons who have survived heart attacks and are experiencing ventricular arrhythmias," Cairns said.

The study was designed as a randomized, placebo-controlled clinical trial among heart attack survivors. The drug was tested on 1,202 patients in 36 hospitals across Canada.

The patients were given either a placebo or amiodarone in a reducing dosage over the period, and most were followed for two years.

As well as Cairns, the other principal investigators were McMaster University professors Dr. Stuart Connolly, Michael Gent and Robin Roberts.

Before joining UBC, Cairns was a member of the Dept. of Medicine at McMaster for 21 years. His research interests include unstable angina and acute myocardial infarction.