Zoll Firm Lecture Series Atrial Fibrillation 2008 Zoll Firm Lecture Series

Zoll Firm Lecture Series Atrial fibrillation is associated with a wide variety of clinical situations: Hypertension CAD CHF Advanced age Valvular heart disease (especially MS) Post-operative (especially after cardiac surgery) Physiologic stress (infection, SIRS…etc). Pulmonary embolism Chronic lung disease Hyperthyroidism WPW “lone atrial fibrillation” 2008 Zoll Firm Lecture Series

Atrial fibrillation nonmenclature Lone atrial fibrillation Patients with a-fib without clinical or echocardiographic evidence of heart disease. New onset atrial fibrillation First recognized episode Recurrent atrial fibrillation More than 1 episode has occured Paroxysmal atrial fibrillation Recurrent atrial fibrilation that has returned to sinus rhythm Permanent atrial fibrillation 2008 Zoll Firm Lecture Series

Morbidity of atrial fibrillation Symptoms associated with fast ventricular rate, lost of AV synchrony, and loss of RR-regularity Embolic event/Stroke “conversion pauses” Patient with atrial fibrillation often have sick sinus syndrome and experiences a prolonged pause when they convert back to sinus rhythm which can lead to syncope. 2008 Zoll Firm Lecture Series

Zoll Firm Lecture Series Symptoms When the ventricular rate is very fast, does not have enough time to fill- lower output congestion backs to the lungs Loss of AV-synchrony leads to loss of “atrial kick” Symptoms often includes palpitations, dypsnea, fatigue, dizziness, chest discomfort. Worst in patient with a thick, non-compliant ventricle Needs time to fill Needs the atrial kick to fill Includes pt with AS, HOCM, massive LVH…etc. 2008 Zoll Firm Lecture Series

Zoll Firm Lecture Series Treatment If the patient is unstable, needs to cardiovert immediately Understand that there is a risk of stroke in patient who are not therapeutically anticoagulated. Otherwise, it is not clear whether rhythm control or rate control is better. 5 clinical trials randomized patients to a strategy of rate control vs rhythm control (AFFIRM, RACE, PIAF, STAF, and HOT-CAFÉ). AFFIRM and RACE were the largest of the 5 trials. All found no major difference in the primary end-point between the two strategies. The primary reason to attempt rhythm control for patients who are highly symptomatic with atrial fibrillation and/or who cannot be well rate controlled. 2008 Zoll Firm Lecture Series

“Rhythm control”- Cardioversion For a-fib>48 or of unknown duration, cardioversion should be delayed until pts have been therapeutically anticoagulated for 4 weeks or if TEE shows no thrombus Electrical- effective (70-90%), pre-treatment with antiarrhythmic agents may increase likelihood of success. often requires sedation (pt preferably fasted), can be complicated by pulmonary edema due to transient stunning Pharmacologic Not as effective (40-70%) Dofetilide, flecainide, ibutilide, propafeone > amiodarone if <7 days duration; dofetilide> amiodarone + ibutilide if >7 days duration. Can be proarrythmic- some agents can induce torsades Many people thinks that most patients deserves one trial of cardioversion if the a-fib is diagnosed for the 1st time. 2008 Zoll Firm Lecture Series

“Rhythm control”- maintanance of sinus rhythm Class Ia (quinidine, disopyramide, procainamide), class Ic (flecainide, propafenone), and class III (amiodarone, sotalol, dofetilide), class I associated with increase mortality. Amiodarone is the most effective agent and can be used in the setting of LV dysfunction, CAD, LVH…etc. However, it has a lot of side effects (pulmonary, thyroid…etc). Sotalol less effective but safe in pts with CAD. Dofetilide safe in patients with heart failure but can induce torsades and require an in-patient load. In patients without structural heart disease, class Ic agents such as flecainide and propafenone are a reasonable choice. 2008 Zoll Firm Lecture Series

Zoll Firm Lecture Series Rate control Urgent treatment in very symptomatic but not overtly unstable patients often requires IV medication. Long term maintenance is with oral medication. B-blocker, non-dihydropyridine Ca channel blockers (verapamil, diltiazem), digoxin, and to some degree amiodarone are effective. In general, beta blockers are more effective during exercise compared to at rest. Digoxin is more effective at rest compared to exercise. Ca channel blockers maybe effective in both situations Co-existing conditions often dictate use- i.e. pts with systolic heart failure gets beta blockers, pts with low BP gets digoxin…etc. Needs to assess response to treatment at rest and with exertion using Holters, exercise test…etc. 2008 Zoll Firm Lecture Series

Thromboembolic risk/Anticoagulation C- congestive heart failure (1), H- hypertension (1), A- age >=75 (1), D- diabetis mellitus (1), S- previous history of Stroke (2) Event per 100 person/years CHADS2 Warfarin no warfarin NNT 0.25 0.49 417 1 0.72 1.52 125 2 1.27 2.5 81 3 2.2 5.27 33 4 2.35 6.02 27 5/6 4.6 6.88 44 Patients with CHADS score >1 needs to be anticoagulated with coumadin. However, they don’t need to be bridged with heparin for surgery unless they have rheumatic mitral stenosis. 2008 Zoll Firm Lecture Series

Zoll Firm Lecture Series Catheter ablation Most of the focus of initiation of atrial fibrillation occurs around the pulmonary veins. Radiofrequency catheter ablation techniques to “electrically isolate” the pulmonary veins is effective in reducing future episodes of atrial fibrillation with an efficacy of approximately 50-70% in one year. Probably most effective in patients with structurally normal hearts, paroxysmal atrial fibrillation who has a shorter duration of symptoms The procedures can be complicated by cardiac tamponde, pulmnary vein stenosis…etc. 2008 Zoll Firm Lecture Series

Suggested algorithm for management of atrial fibrillation 2008 Zoll Firm Lecture Series