Key result
Intravenous RSD1235 terminates recent-onset AF in ~61% of patients compared to placebo.
Why the study?
Anti-arrhythmic drugs currently available to terminate recent onset atrial fibrillation have limited efficacy and safety, prompting evaluation of the novel agent RSD1235.
RCT (n=56)
double-blinded
randomized
Yes
Absolute Event Rate: 61% vs 5%
p-value: p=< 0.0005
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“If half the patients who would otherwise require electrical cardioversion can be fixed by a relatively brief infusion of a drug, under careful monitoring, but not with a risk of large complications, that's a worthwhile addition to what we have available.”
“With a few hundred patients treated so far, conversion of atrial fibrillation using RSD1235 has not led to any cases of torsades de pointes, which makes the drug more attractive than ibutilide, the only drug with Food and Drug Administration approval for conversion of atrial fibrillation.”
“I don't think a drug that potentially could be used in a very large population of patients should count a couple hundred patients exposed as adequate to define the benefits and the risks.”
Randomized trial demonstrates the efficacy of RSD1235 for restoring sinus rhythm in recent-onset atrial fibrillation, suggesting a targeted pharmacological cardioversion option.
OBJECTIVES: The purpose of this study was to determine the efficacy and safety of intravenous RSD1235 in terminating recent onset atrial fibrillation (AF). BACKGROUND: Anti-arrhythmic drugs currently available to terminate AF have limited efficacy and safety. RSD1235 is a novel atrial selective anti-arrhythmic drug. METHODS: This was a phase II, multi-centered, randomized, double-blinded, step-dose, placebo-controlled, parallel group study. Fifty-six patients from 15 U.S. and Canadian sites with AF of 3 to 72 h duration were randomized to one of two RSD1235 dose groups or to placebo. The two RSD1235 groups were RSD-1 (0.5 mg/kg followed by 1 mg/kg) or RSD-2 (2 mg/kg followed by 3 mg/kg), by intravenous infusion over 10 min; a second dose was given only if AF was present. The primary end point was termination of AF during infusion or within 30-min after the last infusion. Secondary end points included the number of patients in sinus rhythm at 0.5, 1, and 24 h post-last infusion and time to conversion to sinus rhythm. RESULTS: The RSD-2 dose showed significant differences over placebo in: 1) termination of AF (61% vs. 5%, p < 0.0005); 2) patients in sinus rhythm at 30 min (56% vs. 5%, p < 0.001); 3) sinus rhythm at 1 h (53% vs. 5%, p = 0.0014); and 4) median time to conversion to SR (14 vs. 162 min, p = 0.016). There were no serious adverse events related to RSD1235. CONCLUSIONS: RSD1235, a new atrial-selective anti-arrhythmic agent, appears to be efficacious and safe for converting recent onset AF to sinus rhythm.
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Roy et al. (2004) conducted an RCT in recent onset atrial fibrillation (n=56). RSD1235 vs. placebo was evaluated on termination of AF during infusion or within 30-min after the last infusion (p=< 0.0005). Intravenous RSD1235 (2 mg/kg followed by 3 mg/kg) significantly increased the termination of recent onset atrial fibrillation compared to placebo (61% vs. 5%, p < 0.0005).