new atrial fibrillation guidelines

new guidelines on management of atrial fibrillation from am heart assn and am acad of cardiol (see afib aha guidelines circ 2014 in dropbox, or 10.1016/j.jacc.2014.03.022). long article, so will summarize a few of the newer or more significant recommendations:

1. antithrombotic therapy -- individualized/shared decision-making. 

        --warfarin if mechanical valve (range 2-3 or 2.5-3.5, depending on type of valve/location). 

        --for patients with nonvalvular afib with prior stroke, TIA, or CHA2DS2--VASc score of 2 or greater, recommend oral anticoag. [note they are not using the older CHADS2 score.  see below for the CHA2DS2--VASc instrument.]  options: warfarin with INR 2-3 (level of evidence A); or dabigatran, rivaroxaban, or apixaban (level of evidence B) [ie, they added these factor Xa inhibitors to the list.  though i have sent out recent blogs on the apparent understating of risks of dabigatran in particular]. not use dabigatran in patients with mechanical valves or dabigatran and rivoraxaban if ESRD or hemodialysis

        --they still recommend INR monitoring at least weekly til INR in range, then at least monthly [though, fyi, there was a recent article suggesting that rock-stable patients could be checked every 3 months]

        --for patients with nonvalvular AF and CHA2DS2--VASc score of 0, "it is reasonable to omit antithrombotic therapy". for a score of 1, can do nothing, use aspirin, or anticoagulate [they are downgrading the recommendation that aspirin should be used in low risk patients, given relative paucity of studies -- SPAF is only study showing benefit of aspirin alone]

2. treat atrial flutter the same way

3. in terms of rate control, rate <80 is reasonable for symptomatic management (mostly by b-blocker or nondihydropyridine calcium channel blocker). but (per new study) resting heart rate <110 may be reasonable if patient asymptomatic and LV systolic function normal [my caveat here: i have a patient with baseline normal heart function, in afib and with mitral valve replacement, who developed severe symptomatic tachycardia-mediated cardiomyopathy at heart rate of 110, with LVEF of <20%, completely reversed after 2-3 months of lowered ventricular rate -- this is supposed to happen at somewhat higher rates, on the order of 130, but either it can happen at lower rates or this patient had higher rates at other times of the day. in any event, i am hesitiant to target 110 from this anecdotal experience. and my many patients with afib do fine at rates in the 80s...]. in pts with exertional symptoms, consider checking pulse with exertion and titrating meds.

4. consider AV nodal ablation if medical management inadequate and rhythm control not achievable

5. consider cardioversion, esp if persistent sx with rate control, younger pt, hx of tachycardia-mediated cardiomyop, first episode of afib, or if afib precipitated by acute illness. if afib >48hrs, then 3 weeks of anticoagulation before (or can do TEE and if negative, cardiovert right away).  then, in any case, anticoag for 4 weeks after [no change in these recs]

6. hypertrophic cardiomyopathy: anticoagulate independent of CHA2DS2--VASc score. antiarrhythmics to prevent recurrent afib, or catheter ablation if not tolerated/not work

7. they note the efficacy of radiofreqency catheter ablation to maintain sinus rhythm, esp in younger patients with paroxysmal afib and little structural heart disease. [there was a recent JAMA article on the RAAFT-2 trial (see afib radiofreq ablation JAMA 2014 in dropbox, or doi:10.1001/jama.2014.467) which randomized 60+ patients with mean age 55 to antiarrhythmic drugs (mostly flecainide, and propafenone) vs radiofrequency ablation, followed 24 months, and found that radiofreq ablation led to 55% vs 72% developing atrial tachyarrhythmia > 30 sec on monitoring, and 47% vs 59% having recurrence of symptomatic atrial arrhythmia.

for the new guidelines, there were industry ties for vice-chair and 4 of 14 members of committee

of note, risk factors for developing AF include increasing age, htn, dm, MI, valv heart dz, chf, obesity, OSA, smoking, alcohol, hyperthyroidism.  there was an intriguing recent RCT in JAMA finding that wt loss decreases afib symptom burden and severity, number of episodes and cumulative duration of afib. also decrease in intraventricular septal thickness (see afib wt reduction JAMA 2013 in dropbox, or doi:10.1001/jama.2013.280521)

also, fyi,  B-type natriuretic peptide or N-terminal pro- B-type natriuretic peptide are elevated in paroxysmal or persistent afib, in absence of chf.

CHA2DS2--VASc (max 9 points):

    --CHF                                                                   --1 point

    --HTN                                                                   --1 point

    --age>= 75 yo                                                      --2 points

    --DM                                                                    --1 point

    --stroke/TIA/thromboemboli                                   --2 points

    --vasc dz (prior MI, PAD, aortic plaque)                   --1 point

    --age 65-74                                                          --1 point

    --female sex                                                         --1 point