儿科心血管系统heartfailure英文二部分

HEART FAILURE,Management of Heart Failure,Treatment Strategies: Ameliorate symptoms Maintain cardiac functional state Reduce mortality rate Reduce hospitalization,Treatment,1. The cause must be removed 2. General management: bed rest, mitigate，oxygen inhalation， reduction of salt intake 3. Drug Treatment,Drug Treatment,Positive inotropic agentscardiac glycosides, phosphodiesterase inhibitorsVasodilatorsDiureticsAngiotensin converting enzyme inhibitors (ACEI)Beta-blockers,治疗,洋地黄类药物：正性肌力，负性传导，负性心率；直接抑制过度的神经内分泌系统。临床常用制剂：地高辛；西地兰。常用剂量：地高辛口服化量：2岁0.05-0.06mg/kg，2岁0.03-0.05mg/kg，维持量为化量的1/5。西地兰静注化量：2岁0.03-0.04mg/kg，2岁0.02-0.03mg/kg。 新生儿用量更少，取婴儿量的1/2至2/3。,治疗-洋地黄类药物,使用方法 化量（饱和量）：适用于急性心衰或重症心衰，首次用化量的1/2量，余量分2次（1/4、1/4）， q4h-q6h或q8h。 维持量：适用于慢性心衰或轻症心衰，维持量为化量的1/5量，分2次口服；或者化量后需继续维持者，于化量后12小时开始予维持量。,治疗-洋地黄类药物,注意事项：用药前了解洋地黄情况；避免用钙剂；注意纠正低血钾。洋地黄中毒 表现：心律失常；消化道症状；神经系统症状等。 处理：停用洋地黄及利尿剂；口服补钾；必要时用抗心律失常药。,Diuretics,Relieve the congestion status by elimination of sodium and water.Indicated in pulmonary congestion with dyspnea and rales and generalized edema ,ascitesAgents used:Thiazideschlorothiazide , chlothalidoneLoop diureticsfurosimide, bumetanide, ethacrynic acidPotassium-sparing diureticsspirolectone, triamterene, amilorideSide effects: hypokalemia, hyperglycemia,ACE-Inhibitors,Rationales of the ACEI treatment for heart failure:Decreases peripheral circulatory resistanceDecreases the blood volumeDecreases the sympathetic activityInhibition of the remodeling process,ACE-Inhibitors,Short-term effectsSymptomatic improvement: approximately 2/3 of cases with severe heart failure show diurea, improvement in dyspnea and less edema.Hemodynamic improvement: increased cardiac output by 25%-30% reduction of PCWP by 20% decreased peripheral resistance by 30% BPdrop 10%-15% Heart rateslightly reducsedN.B. 1st dose hypotension, transient elevation of BUN and creatinin,ACEI treatment of H.F.,Long-term effects : Reduction of mortality and preservationof cardiac function.SAVE study: Cases: post acute myocardial infarction with EF40% Captopril Control PCase No. 1115 1116Mortality rate(42months) RR21% 0.014DevelopmentOf severe H.F. RR 37% 0.001,SOLVE study:,1) Cases of H.F.with symptoms, EF35%Enalapril ControlCase No. 2111 2117 Follow up for 37.4 monthsReduction of the death or development of H.F.by 37% (P0.001),Conclusion of ACEI treatment of heart failure:,ACEI should be used in patients with heart failure irrespective to their underlying causes, if not contra-indicated.Early application of ACEI can postpone the development of congestive heart failureAttention should be paid to hypotension, increased blood Cr content and the side effect of cough.Agent used: Captopril, Enalapril, Perindopril, Lisinopril etc.,Beta-blocker in treatment of H.F.,Adverse effects induced by prolonged excessive sympathetic activity:Increases peripheral resistance-after-loadIncreases heart rateIncreases excitability-arrhythmiasElevation of NE cAMP intracellular Ca+ overload precipitation of apoptosis and cell deathBeta-blockers can induce negative inotropic response,Clinical Trial: US Carvedilol Heart Hailure Study,Carvedilol Placebo RR PNo.of cases 696 398Mortality rate (%) 3.2 7.8 65% 0.001Hospitalization (%) 14.1 19.6 27% 0.036Agents proved to be effective in major clinical trails: Carvedilol, Metaprolol, Bisoprolol,Indications of Beta-blockers in CHF,Beta-blocker is indicated in CHF grade II,III and IV irrespective to its cause if not contraindicatedUsed on top of ACEI and diureticsPreferably initiate the treatment in hospital especially for severe casesStart with a very small dose (usually 1/8 of the target dose), and increase gradually in 1-2 week interval.Watch carefully, adjust the dosage of ACEI or diuretics if necessary,Summary of management of H. F.,Treating the underlying cause and associated diseasesGeneral care daily life adjustmentsDrug therapy:ACEIDiuretics in case presence of congestion Beta-blockersDigoxin if necessary,Acute Left Heart FailurePulmonary edema,Etiological causes: Acute myocardial infarction, Hypertension, Mitral stenosis, etc.Pathophysiology marked increase of the pulmonary blood volume and capillary pressure resulting exudation in alveoli.Clinical features: Severe dyspnea Cough with frothy sputum,blood tinged Full of lung rales Restlessness to mental retardation,Management of Acute Left Heart Failure,Oxygen therapy. Positive pressure oxygenation if necessaryVasodilator therapy: Nitroglycerin,nitropruside I.V.Diuretics: Furosemide I.V.Positive inotropic therapy: Dobutamine, milrinone (N.B. cardiac glycoside is contraind