The PALLAS trial studied the drug dronedarone for preventing major cardiovascular events in high-risk patients with permanent atrial fibrillation. The trial was stopped early after enrolling 3236 patients because patients receiving dronedarone had a significant increase in cardiovascular events such as stroke, heart failure, cardiovascular death, and arrhythmic death. Comments from researchers on the trial suggested dronedarone may only be safely used in patients with intermittent atrial fibrillation who have the potential to maintain sinus rhythm.

1. PALLAS (Permanent Atrial Fibrillation
Outcome Study Using Dronedarone on
Top of Standard Therapy)

2. PALLAS (Permanent Atrial Fibrillation Outcome Study
Using Dronedarone on Top of Standard Therapy)
SJ Connolly (Population Health Research Institute and McMaster University, Hamilton, ON)
American Heart Association 2011 Scientific Sessions
• A study to demonstrate the efficacy of dronedarone in preventing major CV
events (stroke, systemic arterial embolism, MI or CV death) or unplanned CV
hospitalization or death from any cause in patients with permanent AF and
additional risk factors
• Population and treatment:
>10 000 (planned) high-CV-risk patients with permanent AF
Randomized to dronedarone or placebo
• Primary end points:
Time from randomization to first occurrence of stroke, systemic arterial
embolism, MI, or CV death
Time from randomization to first occurrence of unscheduled CV
hospitalization or death from any cause
AF=atrial fibrillation

3. PALLAS: Results
• Trial was stopped early at an enrollment of 3236 patients due to a significant
increase in CV events in patients receiving dronedarone: largely due to stroke, HF,
CV death, and arrhythmic death
Hazard ratio (95% CI) for clinical end points over a median of 3.5 months
End points Hazard ratio (95% CI) p
Co–primary end point: stroke, MI, systemic embolism, or CV death 2.29 (1.34–3.94) 0.002
Co–primary end point: death or unplanned CV hospitalization 1.95 (1.45–2.62) <0.001
Mortality 1.94 (0.99–3.79) 0.049
CV death 2.11 (1.00–4.49) 0.046
Arrhythmic death 3.26 (1.06–10.00) 0.03
Stroke 2.32 (1.11–4.88) 0.02
HF hospitalization 1.81 (1.10–2.99) 0.02
HF event or hospitalization 2.16 (1.57–2.98) <0.001
HF=heart failure

4. PALLAS: Commentary*
"[The use of dronedarone in patients at risk for heart failure] pushes us toward a
more limited population in which we can use it safely: symptomatic patients with
intermittent atrial fibrillation."
- Dr Stuart J Connolly
"It all comes down to making sure that if you treat somebody with atrial fib with this
drug, in fact there's a prayer and potential for them to maintain sinus rhythm."
- Dr Peter Kowey
*All comments from PALLAS: Dronedarone a hazard in high-CV-risk patients with permanent AF
(http://www.theheart.org/article/1310273.do)

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