3.CONGESTIVE HEART FE for UG_103330.pptx

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1. CONGESTIVE HEART FAILURE IN CHILDREN Dr. Emmanuel Rusingiza Pediatric Cardiology CHUK

2. Objectives Understand the definition of congestive heart failure Describe the pathophysiology and clinical presentations of CHF Understand the rationale of CHF management

3. Prerequisites : Basic anatomy and physiology of the heart

4. Physiologie Principales propriétés du cœur: Contraction du ventricule : traduite pression intracavitaire nécessaire à l ’ ouverture des valves artérielles (fonction de post-charge). Compliance du ventricule : traduite par pression intracavitaire secondaire à l ’ étirement des fibres en diastole en l ’ absence de contraction ventriculaire

5. Adults without ASD closed ductus QP = QS Ao 100 RA 3 V LA 8 QS QP PA 20 P ESV EDV L R

6. Cardiac Cycle

7. 1. Definition of Heart Failure CHF is a clinical syndrome in which the heart is unable to pump enough blood to the body to meet its needs , to dispose a systemic and pulmonary venous return adequately. Common pathophysiologic categories that cause heart failure: ventricular pump dysfunction volume overload pressure overload combination of volume and pressure overload.

8. 2. Causes Congenital heart defects ( VSD, AVSD, PDA…) Acquired heart diseases (Rheumatic valvular heart disease…) Myocardial diseases (cardiomyopathies) Pericardial diseases ( tamponade , constrictive pericarditis) Tachyarrhythmia and heart block Non cardiac factors: anemia, hypertension, renal failure, sepsis...

9. Congenital Heart Diseases

10. Acquired Heart Diseases Acute Rheumatic carditis and Rheumatic valvular heart disease +++ Viral myocarditis ++ Endocardial fibroelastosis (rare primary myocardial disease) Myocarditis associated with Kawasaki disease Dilated cardiomyopathy+++ (infectious, metabolic, anthracyclines …) Cardiomyopathy associated with muscular dystrophy and Friedreich’s ataxia Post cardiac surgery ( Fontan operation, TOF…) Miscellaneous: SVT, complete heart block, severe anemia, cor pulmonale , systemic HTN, carnitine deficiency…)

11. 3. Pathophysiology Reference made to Frank- Starling Law: As end-diastolic volume (preload) increases, the healthy heart increases cardiac output until the maximum is reached and cardiac output can be no longer augmented . But: failing heart does not achieve the maximum cardiac output as the normal heart and symptoms occur ( dyspnea and hepatomegaly… )

12. Compensatory mechanisms 1: The increased preload results in increased wall tension , which in turn increases oxygen consumption. Increased in wall tension is also seen in dilated ventricular cavity, according to Laplace law: Wall stress= pressure x radius/2 x wall thickness Cardiac hypertrophy develops to balance the increased pressure and keep the wall stress unchanged.

13. Compensatory mechanisms 2 : Activation of Sympathetic nervous system & Renin-angiotensin- aldosterone system

14. Sympathetic nervous system: s ympathetic tone secondary to increased adrenal secretion of epinephrine and norepinephrine : increased cardiac output by increased HR and myocardial contractility Renin-angiotensin- aldosterone system: blood flow in the kidneys causes marked increase in renin output and this in turn causes the formation of angiotensin II : reabsorption of water and sodium and vasoconstriction

15. What next with the activation of the 2 neurohormonal mechanisms: Although beneficiary initially, chronic stimulation of these systems may be deleterious in the natural history of myocardial dysfunction!

16. Chronic adrenergic stimulation leads to adverse myocardial effect including increased afterload, hypermetabolism , arrythmogenesis and direct myocardial toxicity Angiotensin II: may cause a trophic response in vascular smooth muscle (with vasoconstriction) and myocardial hypertrophy. Promotes myocardial fibrosis .

17. Hence, maladaptive role in CHF by initiating fibrosis and altering ventricular compliance overtime… ---> reasons for using beta-blockers and ACE inhibitors in the treatment of Heart Failure

18. 3. Diagnosis Relies on medical history: Infants: poor feeding of recent onset, tachypnea that worsen during feeding, poor weight gain cold sweats of the forehead. Older children complain of: shortness of breathing with activities, easy fatigability, puffy eyelids or swollen feet Cough, bloody sputum

19. Heart failure classification NYHA Description Question to ask patient Class I Patients with cardiac disease but no resulting limitation of physical activity. Ordinary physical activity does not cause symptoms. “ Is there any activity which you cannot do because you get short of breath? ” Class II Patients with cardiac disease resulting in mild limitation of physical activity. Patients are comfortable at rest. Ordinary physical activity (farming, running, carrying water, climbing a hill) causes symptoms. “ Do you feel short of breath while walking up a steep hill? ” Class III Patients with cardiac disease resulting in moderate limitation of physical activity. Patients are comfortable at rest. Less than ordinary physical activity (light housework, walking on flat ground) causes symptoms. “ Do you feel short of breath while walking around the house or doing light work around the house? ” Class IV Patients with cardiac disease resulting in severe limitation of physical activity. Patients have symptoms at rest. Any physical activity causes symptoms . “ Do you feel short of breath while you are sitting at rest? ”    

20. Modified Ross Heart Failure Classification for Children Class Criteria I Asymptomatic II Mild tachypnea or diaphoresis with feeding in infants Dyspnea on exertion in older children III Marked tachypnea or diaphoresis with feeding in infants Marked dyspnea on exertion Prolonged feeding times with growth failure IV Symptoms such as tachypnea, retractions, grunting, or diaphoresis at rest Circulation Heart Failure, Jan 2009

21. Physical exam Compensatory responses to impaired cardiac function: tachycardia, gallop rhythm , cardiomegaly , weak pulses, signs of increased sympathetic discharge such growth failure, perspiration , cold and wet skin Pulmonary venous congestion (from left sided failure ): tachypnea resulting in difficulty in feeding in infancy , dyspnea on exertion , wheezing and pulmonary crackles are occasionally audible.

22. Systemic venous congestion ( right sided failure): hepatomegaly, puffy eyelids , distended neck veins and ankle edema are not seen in infants.

23. 4. Investigations Non specific tests : FBC, urea and creatinine , electrolytes ( Na + , K + , Ca ++ , Mg ++ ), Natriuretric peptides Chest X-ray : confirms cardiomegaly and pulmonary congestion Echocardiography : size of chambers and function of ventricular chambers Electrocardiography : helps to determine type of heart defect causing CHF Cardiac catheterization : for endomyocardial biopsy to establish cause of heart failure ( viral, genetic analysis, metabolic disorder…)

24. 5. Management Consists of: Control of heart failure estate : use of multiple drugs ( diuretics, inotropics , after-load reducing agents along with support measures). Treatment of contributing or precipitating causes ( infection, anemia, arrythmia …) Elimination of underlying causes : most desirable for complete cure like surgical correction of CHD, valvular surgery in case of RHD…

25. General measures: to improve congestion and nutrition 1. Keep patient in semi upright position to relieve respiratory distress 2. Provide Oxygen, use appropriate device to clinical status. 3. Adequate calories and fluid to permit weight gain: high caloric intake 150-160Kcal/kg/day by fortification of feeding Note: Frequent small feedings are better tolerated than large feedings in infants, intermittent or continuous NG( nasogastric ) feeding is indicated.

26. 4. Salt restriction in older children: less than 0.5g/day and avoid salty snacks; 5. Bed rest, availability of TV and computer games for entertainment is helpful in older children; 6. Intubation and positive- pressure ventilation are required if respiratory failure accompanies heart failure; 7. Daily weight is essential in hospitalized patients 8. Education of parents (and child if applicable)

27. Drugs Therapy 3 majors classes: Inotropic agents Diuretics Afterload-reducing agents

28. a. Inotropic agents Aims: U sed during acute exacerbations of heart failure or cardiogenic chock To improve cardiac output and to stabilize patients awaiting heart transplantation

29. Catecholamines   improves myocardial contractility and may have an additional beneficial effect on peripheral vascular beds. Dopamine is the preferred drug during decompensated heart failure Dobutamine has the additive effect of reducing afterload. Dosage: 5 – 10micrograms/kg/min Milrinone : phosphodiesterase III inhibitor, preferred drug in decompensated heart failure, increases contractility and reduces afterload without a significant increase in myocardial oxygen consumption Dosage: 0.25 - 1 micrograms/kg/min

30. b. Diuretics Reduce preload and improve congestive symptoms Do not improve cardiac output or myocardial contractility 3 main classes ( see next table) Side effects: alteration of serum electrolytes and acid-base equilibrium.

31. Class Action Dosage Side-effect Thiazidic diuretics : - Chlorothiazide - Hydrochlorothiazide Inhibit reabsorption of sodium and chloride ions from the distal convoluted tubules of kidneys Hydrochlorothiazide Oral : 2-4mg/kg/day in 2-3 divided doses Hyponatremia Hypokalemia hypochloremia Note: Less used Rapid- acting diuretic ( Loop diuretics )+++: Furosemide Bumetanide Torsenide ethacrynic acid Inhibits sodium and chloride reabsorption at the Loop of Henle Furosemode IV: 1-2mg/kg/dose. Oral: 2-3mg/kg/in 3 divided doses Hyponatremia Hypokalemia hypochloremic alkalosis Renal insufficency Nephrocalcinosis and ototoxicity ( long term therapy) Aldosterone antagonist “potassium-sparing diuretic” : - spironolactone. Decrease sodium reabsorption and potassium excretion in the collecting ducts Oral: 1-3mg/kg/day in 2-3 divided doses Hyperkalemia Gynecomastia (with spironolactone).

32. c. Digitalis Glycosides Digoxin most commonly used digitalis Effect: Positive inotropic effect and a negative chronotropic effect that slows atrial conduction, vagotonic properties that counter symptoms and signs mediated by the activation of sympathetic nervous system in heart failure used in the treatment of infants and children with advanced heart failure, Potential adverse effects (arrhythmias) are rare with this lower level Dose: 10microgram/kg/day in 2 divided doses

33. d . Afterload reducing Agents   Class Action Dosage Side action Angiotensin-converting enzyme inhibitors   E .g: Captopril Enalapril decreasing afterload, increase cardiac output and promoting reversal of LV remodeling with long-term use Captopril Oral: 0.5-4mg/kg/day 1- 4 times a day Enalapril Oral: 0.1mg/kg once or twice daily Hypotension Dizziness Neutropenia Proteinuria Angiotensin receptor blockers   Idem There is a paucity of data in the use of ARBs In children with heart failure Hypotension Dizziness or Syncope

34. e. Beta-adrenergic blockers Effect : counteract the maladaptive effects of chronic sympathetic activation of the myocardium. shown to improve patient survival, reverse LV remodeling, and decrease myocardial fibrosis in adults , Limited evidence in children, use for those with marked heart failure M ust be stable on other heart failure medication ( diuretics, digoxin and an ACE inhibitor Carvedilol is most commonly used

35. Carvedilol dosage: Oral 0.05 mg/kg per dose given twice a day, increase ( double) every two weeks to minimize side effects Max dose: 0.4mg/kg twice a day Side effects : dizziness, fatigue, hypotension, bradycardia , bronchospasm, and hypoglycemia

36. Cardiac surgery/ catheterization Indicated for heart defects when technically feasible (VSD, AVSD, ASD, PDA, Rheumatic valvular diseases…) Cardiac transplantation for patient with progressively deteriorating cardiomyopathy despite max medical treatment.

37. Recommendations of ISHLT, AHA 2004 Structural heart disease with normal ventricular function: surgical or catheter-based interventions Ventricular pump dysfunction or those who require stabilization before surgical or catheter-based correction: therapy based on the severity of heart failure

38. Recommendations by ISHLT, AHA 2004 Stage A: Patients at-risk for heart failure with normal cardiac function and size: No therapeutic intervention. Stage B : Asymptomatic patients with abnormal systemic ventricular function: ACE inhibitors. Stage C : Patients with current or past symptoms and structural or functional heart disease: ACE inhibitors, aldosterone antagonists, beta-blockers, low dose digoxin, and oral diuretic therapy . Stage D : Patients with end-stage heart failure who are refractory to oral medical therapy: Intravenous inotropes and diuretics, positive pressure ventilation, mechanical circulatory support, and subsequent heart transplantation

39. 6. Complications Thromboembolism ( intracardiac thrombus, stroke) Prevention: AAS if moderate LV dysfunction and warfarin or LM Heparin if severe LV dysfunction Arrhythmias (sustained atrial and ventricular tachyarrhythmia) Ventricular dyssynchrony ( caused by Intraventricular conduction delay or left bundle branch block) Death

40. 7. Conclusion Heart failure is a clinical syndrome when the heart is unable to meet the needs of the body Management is based on the etiology and severity of heart failure Parents/patient education and appropriate follow-up are critical