What to do when Atrial Fib with RVR will not Electrically Cardiovert. And how do you measure the QT in Atrial Fib?

Conclusions.The efficacy of transthoracic cardioversion for converting atrial fibrillation to sinus rhythm was enhanced by pretreatment with ibutilide. However, use of this drug should be avoided in patients with very low ejection fractions. (N Engl J Med 1999;340:1849-54.) Important aspects to this study:They included patients who had had a fib for less than 48 hours.They excluded patients with a fib for longer than 48 hours unless they proved, by TE echo, to not have an atrial clot OR unless they anticoagulated them for 3 weeks first.Therefore, our patients who have been in afib< 48 hours, or who have been on anticoagulants, apply.They excluded anyone with a QTc> 480ms because ibutilide can lead to torsade.  As far as I can tell, they did not state their correction formula or how they measured the raw QT and in what lead.The dose was 1mg over 10 minutes.2 of 64 patients who received ibutilide went intotorsades de pointes. Both had low ejection fractions,<20% and both were easily controlled. The authors recommend not using ibutilide for this indication in stable patients if the EF is< 30%. However, it is still an option in unstable patients. Ibutilide increased the QTc significantly (432+/-37 before vs. 482+/-49 afterward).Although the point is not discussed in the paper, I would not send such a patient home unless the QT is corrected, by time or magnesium._____________________Thisemergency department study also had a 100% conversion rate with...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs