Atrial Fibrillation & Flutter¶
Matt Gayoso
Background¶
- AF: 12-lead EKG with absence of p-waves and irregularly irregular QRS complexes
- Flutter: sawtooth atrial F waves (300 BPM) with regular or regularly irregular QRS complexes
- Ventricular rate ratio of F waves: V waves ~150 (2:1), ~100 (3:1), or ~75 (4:1)
- 3 classifications
- Paroxysmal (terminates within 7 days)
- Persistent (persisting beyond 7 days)
- Permanent (normal rhythm cannot be restored)
- Rapid ventricular response (RVR) is HR > 100 (ie AF/Flutter w/ tachycardia)
- AF/RVR is far more often a consequence of hypotension than the cause of it
Evaluation¶
- Causes: Mnemonic “H PIRATES”
- Hypertension
- Pneumonia, Pericarditis, Post-op
- Ischemia (rare)
- Rheumatic Valve
- Atrial Myxoma or Accessory Pathway
- Thyrotoxicosis
- Ethanol or Excess Volume
- Sick sinus, Sepsis
Management¶
- Treatment goals
- Rate control, Goal HR \< 110 (RACE II)
- Rhythm control (if indicated)
- Stroke prevention (CHADS2VASc)
Rate control:¶
- RVR ~ sinus tach of AF; Always work to address the underlying cause (infection, volume overload, etc). Rate control is rarely an emergency unless the patient is unstable
- If stable with RVR (SBP >90)
- IV if HR > 130 or symptomatic (metop 5 mg IV or dilt 15-20 mg IV), otherwise do PO
- AV nodal blocking agents
- B-blockers: Start with metop tartrate (titratable) consolidate to succinate. Avoid in decompensated or borderline HF
- Calcium channel blockers (diltiazem): avoid in HFrEF
- Peri stable (SBPs 80s-90 with preserved perfusion)
- Amiodarone: Consider if decompensated HF, accessory pathway, anti-coagulated. Caution that you may cardiovert pt (stroke risk)
- Unstable (SBPs \<80)
- Cardioversion
Rhythm control¶
- New onset a-fib (first time diagnosis): most pts will be a candidate for trial of cardioversion
- If onset clearly within 48 hours, can proceed without TEE. Often TEE is done anyway (pt may have had intermittent asymp AF)
- If onset >48 hours or unclear, will need TEE to rule out LAA thrombus
- Pharmacologic options include class 1C: flecainide, propafenone
(avoid in structural heart disease) and class 3: Amiodarone,
dronedarone, sotalol, ibutilide, dofetilide (some require loading
inpt)
- Caution using antiarrhythmics in any pt you wouldn't electrically cardiovert without TEE
- Consider EP consult for ablation in symptomatic paroxysmal or persistent AF refractory to anti-arrhythmic drugs, AF in HFrEF, or flutter
Stroke Prevention (for AF and flutter)¶
- CHA2DS2-VASc risk score >2 in M or >3 in F should prompt long term AC in AF persisting >48 hours
- DOACs (apixaban, dabigatran, edoxaban, rivaroxaban) are preferred to warfarin except in moderate to severe MS or mechanical valve
- If cardioversion planned for new onset AF, start AC as soon as possible
- Post-cardioversion, anticoagulate for at least 4 weeks due to atrial stunning and stroke risk
- If no contraindications or procedures, continue anticoagulation while inpatient
- Typically do not need to bridge AC for AF in the setting of procedures unless mechanical valve is present. Decide on a case by-case basis
- Left atrial appendage closure can be considered in those with increased risk of bleeding (WATCHMAN, Amulet devices)