Ch HF in Early Childhood
-#1 bc of CHD- L to R shunt (VSD, AVSD, PDA, Truncus, AP Window, single ventricle w incr Qp, PA+IVS and large AP collats, TAPVR w/o obst)
-as PVR drops, incr Qp, decr Qs; and drop in Hgb as a neonate...
-may have steal fr coronary vessels into PAs as PVR drops--> myocardial ischemia/dysfx
-Sx = fussy, poor PO, incr RR, diaphoresis, +/- CV shock
-Types that present as early HF: idiopathic, endocardial fibroelastosis, mitochondrial dz, storage dz, carnitine defic, HCM, myocarditis
-Non cardiac causes: renal failure, sepsis
Ch HF in Childhood/Adolescence
Unoperated CHD
-L Heart Failure- w AV vlv regurg - eg AVSD, ccTGA, AR
-Infective Endocarditis
-progressive sev LVOTO
-R Heart Failure- Ebstein anomaly with incr in TR +/- assoc arrythmias
-sev incr in PVR w intracardiac or GA shunt (Eisenmenger synd) may have RV dysfx
-TR or PR
Postop CHD
-L Heart Failure- residual L to R shunt, LVOTO, valvar regurg
-e.g.- AS, AR, truncal stenosis/regurg, sev AV vlv regurg p AVC repair, systemic RV dysfx, TR
-Fontan failure in single ventricle pt
-R Heart Failure- pulm htn, resid RVOTO/conduit obst, PR
-ventricular dyssynchrony
Acquired Heart Disease
-h/o KD
-myocarditis
-pericarditis
-valvulitis
-Rh fever/RHD w AR/MR vlv dysfx
-Infective Endocarditis
-DCM, HCM, p radiaton/chemo
-muscular dystrophy, mito d/o, etc
-Marfan's w MVP may get HF if incr PR or AR bc of dilated Ao root
-Sickle pt w myocardial ischemia/infarct
-core pulmonale - heart failure fr phtn/CLD
Chronic Heart Failure Treatment
-M&A recognize the misnomor of CHF for pulm overcirc, given that it isn't bc of ventric dysfx, but also note that both involve similar neurohormonal responses...
-Diuretics
-No proof they improve survival, but essential to Tx fluid OD, decr Sx, and decr SVR and PVR
-Non K sparing diuretics (lasix) activate Renin-Angiotensin-Aldosterone syst & Symp n syst
-and they affect renal fx
-Pts eventually may get less responsive to loop diuretics, so ad thiazides
-Metolazone (a thiazide) + loop diuretic can be best for diuresis in edemetous pts or diurtc resistnt pts
-Spironolactone is K sparing. --> benefit not so much bc of diuresis but other effects- blocks aldosterone which decreases endothelial vasomotor reactivity and incr myocardial fibrosis ==> Spiro does reduce mortality in adults
-Digoxin
-inhib Na-K ATPase pump in myocardium--> promote Na-Ca exchange--> incr intracellular Ca--> improve contractility
-modultes neurohormonal syst--> improve baroR' fx, incr vagal tone, sympathoinhibitory effects, decr circulating NE [ ], ?aldosterone antag effects
-indicated in adults w LV syst dysfx who have/had Sx
-No mortality benefit shown in adults
-In adults, withdrawal of digox--> worse HF sx and exercise tolerance
-In adults, digox--> less Sx and less hospitalization for HF, and higher LV EF, better treadmill
-ACE Inhibitors
-for both ASx and Sx adults w decr LV syst fx
-ACE = kinase II (found on endothel cell membranes, epithelial cells, neuro cells, blood).
-ACEI--> decr AL, decr PL, decr syst wall stress--> incr CO w/o incr HR
-Adults- improve survival w ASx HF
-some nonrandomized evidence of use in kids w L to R shunts
-ARBs
-Angiotensin II R' blockers- block effects of Angio II
-unlike ACEI, ARBs don't incr bradykinin levels so no cough like with ACI
-ARB had better survival than ACEI in survival in once study, but not in a f/u study... (so only rec ARBs if ACEI not tolerated)
-Beta-blockers
-adults w HF- signif sx, LV systfx, survival improvement
-? exact mech of improvement-
-prevent/reverse adrenergically mediated intrinsic myocardial dysfx/remodeling
-the sustained cardiac adrenergic activation--> desensitiz'n of beta R' signal transduction mech and direct damage to myocytes==> ventric dysfx and remodeling w chamber dilation (more sphere shaped chamber) and then HF. So, beta blockers stop this
-maybe also/alternatively up regulate beta R's, bc in HF pts have decr NE/E sensitivity adn beta R' density. But this can't be the whole reason bc some successful b-blockers don't up-regulate beta R's
-Metoprolol & Carvedilol both rec'd for adults w ch HF, w some studies showing carvedilol is better than metoprolol- better BP effect, LV end diast dimension, and mitral valve inflow, and better PAP and PCWP, and better mortality...
-Data in kids:
-Metoprolol - studies showing benefit...
-Mechanical Support
-Resynchronization Tx & Implantable cardioverter-defibrillators (ICDs) both have improved prevention of adult sudden death and improved HF Tx
-resynch in adults improves Sx, excercise, QOL, echo findings of LV fx, and adult survival in pts w HF and interventricular conduction delays
-resynch rec'd for adults w HF w +Sx and electrical dyssynchrony seen as IV conduction delay
-some evidence showing that biventric pacing may be best as there's also mechanical dysync
-few data in kids
-ICDs in adults improve sudden death by 30% compared to anti-arrhythmia drugs in pts w a h/o a malignant ventric arrhythmia.