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Pathophys and Cause ⬇

Cause:

Idiopathic, scar from myocardiopathy (Nejm 1988;318:129) including alcoholic "holiday heart" (Ann IM 1983;98:135), or MI with re-entry, CHF, mitral prolapse syndrome, torsades de pointes (Long QT Syndrome)

In children, young adults (Ann IM 2004;141:829; Nejm 1996;334:1039) and athletes (Jama 1996;276:199) most common causes are IHSS (36%), anomalous coronary arteries (13%), and cardiomyopathies; also congenital heart disease esp tetralogy of Fallot and pulmonic stenosis, long QT syndrome, mitral valve prolapse, cocaine, Marfan's w aortic dissection, Kawasaki's induced coronary aneurysms; rarely Vfib induced by "commotio cordis" blow to chest, eg, baseball, hockey puck, or lacross ball, at ascent of T wave (Nejm 2010;362:917; Jama 2002;287:1142; Nejm 1998;338:1805)

Pathophys:Increased sympathetic tone? (Nejm 1991;325:618)

Epidemiology ⬆ ⬇

Increased with tobacco, caffeine (not so!—Ann IM 1991;114:147), carbon monoxide levels >100 ppm (Ann IM 1990;113:343), alcohol (Nejm 1979;301:1049, 1060), and subtle ST-T wave electrical alternans (Nejm 1994;330:235). Decreased 50% w weekly fish consumption (Jama 1998;279:23)

Signs and Symptoms ⬆ ⬇

Sx:Syncope, which may progress to sudden death

Si:VT is mildly irregular by EKG, unlike very regular PSVT and Aflut with 2:1 block

Course ⬆ ⬇

of sudden death: 47% 2-yr mortality after 1st episode; 86% if no MI, 16% if transmural MI (J. Love 2/86; Nejm 1982;306:1341; 1975;293:259)

If asx, prognosis very good even if complex arrhythmias or VT (Nejm 1985;312:193) even in pts w CHF (Circ 2000;101:40)

of PVCs in asx men: 2 × incidence of later MI or other cardiac event (Ann IM 1992;117:990) but frequent PVCs during or immediately after exercise predict double that rate (10% mortality @ 5 yr—Nejm 2003;348:781)

Complications ⬆ ⬇

r/o digoxin toxicity; mitral valve prolapse (Mitral Valve Prolapse Syndrome); "slow ventricular tachycardia" is a benign regular accelerated idioventricular rhythm <100/min and asx, seen often in inferior MIs; Ashman phenomenon w early beats conducted aberrantly

Lab and Xray ⬆ ⬇

Lab:

Noninv:EKG

  • VT: unlike SVT with aberrancy, Vtach QRSs are wide (85% >0.14 sec, 0% false positives, 30% false negatives—J. Love 7/86), and are not as regular; however, 5% are lteq.gif0.11 s because they originate close to the conduction system (Ann IM 1991;114:460).
  • Brugada criteria (98% overall sensitivity) indicating Vtach rather than SVT w aberrancy (Circ 1991;83:1649):
    1. No precordial RS complex, all pos or all neg, ie, monomorphic Rs or QSs (20% sens), or
    2. Beginning of any precordial R to S nadir >0.10 sec (52% sens), or
    3. AV dissociation present, or
    4. V1-6 criteria
      1. RBBB pattern, R/S <1 and/or Q in V6 and some positive R forces in V1; or
      2. LBBB pattern + Q in V6; and R in V1 or 2 >0.04, or beginning of R to S nadir in V1 or V2 >0.06, or notching of S downstroke in V1 or V2.

Holter monitor w exercise (Nejm 1993;329:445)

Treatment ⬆

Rx:

See algorithm for pts w v arrythmias from (Jama 1999;281:176)

Field defibrillation with external automatic defibrillator by BCLS personnel increases number who are alive at hospital discharge from 20% to 30% ([Seattle] Nejm 1988;319:661), 4% to 5.2% (Ontario—Jama 1999;281:1175) or as high as 75% if provided w/i 3 min (Nejm 2000;343:1206, 1210, 1259), eg, by bystanders using EADs in airports, 10/18 neurologically intact 1 yr later (Nejm 2002;347:1242); in elderly > age 75 yr, CPR 22% success success drops to 12% by 90, worth it? (Nejm 2009;361:22); (Ann IM 1989;111:199 vs Nejm 2009;361:22; Jama 1990;264:2109). If field trial unsuccessful, not worth continuing in ER (Nejm 1991;325:1393). Antiarrhythmic drug-induced type has the highest incidence within the 1st 3 d, so start drug rx in hospital (Nejm 1988;319:257)

Acutely, if sustained, maybe 1st chest thump; then cardioversion with 200-360 J; amiodarone, procainamide, MgSO4, lidocaine, or sotalol

Chronic; huge natural variability day to day and month to month (Nejm 1985;313:1444)

  • implantable pacer/defibrillator (John Love 2/09; Nejm 2008;359;2245; Jama 2006;295:809) for sudden death survivors; or IHSS; or strong family h/o sudden death; or EF <35% and class II or II CHF; or <30% EF and class I; or <40% EF and NSVT and CAD by angio; cost $30 000
  • antiarrhythmics, debatably (Nejm 1999;341:1882) like -blockers even if CHF, RAD, DM, elevated lipids (Ann IM 1995;123:358), eg, metoprolol bid (Nejm 1992;327:987), or sotalol (Nejm 1994;331:31), or amiodarone if CHF present (Nejm 1995;333:77 vs 2005;352:225)

When to let drive car? No consensus but most states require 6-12 asx mo (Ann IM 1991;115:560), but most pts on rx resume sooner and accident rate lower than gen'l population (Nejm 2001;345:391)

Surgical aneurysectomy rarely