Common; supraventricular prematures are not associated with ASHD or sudden death (Ann IM 1969;70:1159)

Sx:Polyuria, palpitations, faintness

Chronic Afib causes embolic CVA in 20% if recent CHF, HT, or previous embolus (Ann IM 1992;116:1) but <1%/yr if none of those and no increase in LA size or LV dyskinesis on echo (Ann IM 1992;116:6); likewise others find rate only 1.3% after 15 yr where no other disease and under age 60 yr (Nejm 1987;317:699); embolic CVA increased × 5 in ASHD type compared to age-matched controls, × 17 in rheumatic (Neurol 1978;28:973).

in SSS, 16% develop arterial emboli (Nejm 1976;295:190)

r/o hyperthyroidism, silent mitral stenosis, alcoholic myocardiopathy, and pulm embolism

Lab:

Chem:TSH

Noninv:

• EKG: Sick sinus syndrome is diagnosed by SVTs alternating w some heart block, and suggested by P <90 after 1-2 mg atropine, or asystole >3 sec after carotid sinus massage.
• MFAT, P >100, and 3 different PR intervals and P-wave morphologies; looks superficially like Afib but digoxin won't help it; WAP is same thing but rate <100
• Holter to find, when intermittent; or better, event monitor (Ann IM 1996;124:16)
• Echo, TEE is 99% specific, 100% sens for LA thrombus (Ann IM 1995;123:817).

Rx:

(Med Let 1991;33:55); all but -blockers may prolong or cause ventricular arrhythmias (Ann IM 1992;117:141)

• Afib:
• Perioperative prevention post-CABG w amiodarone (Nejm 1997;337:1785)
• Rate control: iv diltiazem, -blocker like esmolol, or digoxin but latter's rate is easily overridden by catechol/exercise stimulation (Ann IM 1991;114:573). Outcome of stroke and mortality as good or better than attempts to cardiovert (Nejm 2002;347:1825, 1834, 1883) but no estimates of morbidity outcomes like dyspnea or decr exercise capacity
• Conversion: especially if LA size is <50 mm, use cardioversion; embolic risk post-conversion in 1st 48 h 1% but if >48 h is 5-7% (Ann IM 1997;126:65), but if unknown onset and TEE negative, can start warfarin × 4 wk and procede w immediate cardioversion w/o incr embolic risk (Nejm 2001;344:1411)
• Medical conversion w:
• Amiodarone 30 mg/kg po × 1 converts 87% (NNT = 2) (Am J Cardiol 2000;85:462; Ann IM 1992;116:1017); only safe drug to use with WPW
• Propafenone (Rythmol) 450 mg if <70 kg, 600 mg if >70 kg po, “pill in a pocket” converts 90+% w/i 1 h (Nejm 2004;351:2408), 95% w/i 6 h safely (Ann IM 1997;126:621); or
• Flecainide 200 mg po if <70 kg, 300 mg if >70 kg; or
• Ibutilide (Corvert) 1 mg iv over 10 min, repeat × 1 (Nejm 2004;351:2384); or
• Dofetilide 500 mg po bid (Med Let 2000;42:41) perhaps;
• Digoxin alone is no better than placebo (Ann IM 1987;106:503).
• Electrical cardioversion with sync and w transthoracic (AP better than ant-lateral—Lancet 2003;138:61) or esophageal-transthoracic paddles (R. Fletcher 1/00) if unstable or eventually if meds fail, ok to do even if dig on board as long as levels therapeutic and not toxic, and K⁺ ok (Ann IM 1981;95:676); start at 300 J not lower (Am J Cardiol 2000;86:348)
• Maintenance rx: amiodarone 200 mg po qd cheapest and best (Nejm 2007;356:935) or similar dronedarone (Nejm 2007;357:787); sotalol or other -blocker; verapamil; or digoxin, which controls resting but not exercise rate; quinidine? (Nejm 1998;338:37) po, which holds in NSR better but death rate is 3 × placebo (Circ 1990;82:1106), or procainamide; possibly dofetilide esp if in CHF (Med Let 2000;42:41; Nejm 1999;341:857, 910); or flecainide but tricky (Antiarrhythmics); class 1A drugs may increase mortality (Ann IM 2006;166:719)
• Anticoagulate chronic (Ann IM 2004;141:745; 1999;131:688; Jama 1999;281:182) or intermittent Afib with warfarin to INR >2 but <3.5 best balances risk and benefits (Lancet 1996;348:633, Nejm 1996;335:540, 587, 1995;333:5), which reduces risk of CVA from 7% to 1-2% at any age at least up to age 85 yr (NNT-1.5 = 25) (Circ 1991;84:527; Nejm 1990;323:1505). Annual bleeding risk ~2.5% (Ann IM 1992;116:6). But 10%/yr over age 75 yr (Jags 2005;53:655) though only 1% had fatal bleeds and doses ofen much less. Chronic AF anticoagulation benefit very small (NNT = 200) (Ann IM 1999;131:492) to nonexistent (Ann IM 1994;121:41, 54) if very low risk: age <60 yr, no h/o TIA, no valve disease, normal echo, and no hypertension. And likewise, over age 75-80 yr, risk of anticoagulation-associated intracranial bleed rises × 5, so may only be reasonable if has already had one CNS event (Neurol 2007;68:116). Use ASA if can't use warfarin (Ann IM 1999;131:492; Nejm 1990;323:1505) or pt is low risk (Jama 2001;285:2864). Warfarin to INR <2 is no better than ASA (Nejm 2003;349:1019). Addition of clopidogrel to ASA adds some protection against CVA (NNT-1=100) but at a nearly equal cost of significant bleed (Nejm 2009;360:2066, 2127) (Table 2.4)
• Catheter isolation/ablation of ectopic foci, which are often in pulmonary veins (Nejm 1998;339:659) or the left atrium. 60-80+% successful and may be 1st choice of rx (Jama 2010;303:333; Nejm 2006;354:934, 967; Jama 2005;293:2634) rarely need chronic antiarrythmics and increases EF × 20% and thus improves CHF (Nejm 2004;351:2373)
• Ablation of AV node w permanent pacer (Nejm 2001;344:1043)
• Combined atrial defibrillator/pacer devices (Nejm 2002;346:2062)
• Latrial appendage occlusion to prevent emboli? (Nejm 2009;360:2601)
• AFLUT: carotid sinus pressure trial, then rx as Afib above since >50% go on to Afib and embolic risk is as great (Ann IM 2004;140:265)
• MFAT: rx the primary disease, usually COPD or sepsis; verapamil iv with pretreatment with iv CaCl₂ (Ann IM 1987;107:623) or po for chronic; Mg iv, especially if low; -blockers if no COPD; catheter ablation? (Circ 2002;106:649)
• SSS: permanent pacer preferably w atrial pacing to reduce emboli (Lancet 1994;344:1523), anticoagulation, then medications to control tachycardia

Table 2.4 Treatment of Atrial Fibrillation with Antithrombotic Agents

Risk	Treatment
No risk factors	Aspirin
1 Moderate risk factor	Aspirin or Warfarin
1 High risk factor or >1 moderate risk factor	Warfarin
Risk Factors
Moderate	High
75 years or older	History of embolism, transient ischemic attack, or stroke
Heart failure	Mitral stenosis
Hypertension	Prosthetic heart valve
Left ventricular ejection fraction 35%

Note:Dose/INR: aspirin 81-325 mg daily; INR target 2.0-3.0.