SHA24/091003

Abdullah Alwadai, MD Pediatric cardiology and CSICU Heart failure and transplant Heart center KFSHRC, Riyadh

What a normal heart do everyday:

 consumes more energy than any other organ.  It cycles about 6 kg of ATP every day (20 to 30

times its own weight).

 it beats about 100,000 times  pumps approximately 10 tons of blood

through the body



NEJM 356;11 www.nejm.org march 15, 2007 1141

Definition of HF:  “The failure of cardiac function to maintain

appropriate pulmonary and systemic circulation, with resulting secondary consequences”  HF can also reflect abnormalities of vascular function, systemic and metabolic responses, and abnormalities of other organs such as the kidney.

HF/Cardiomyopathy (CM) - epidemiology:  10% of tertiary-care pediatric cardiology care setting patients

develop symptomatic HF.  50% of them have CHD ( 70% presented in infancy).

 CM in general occur in 8 per 100000 infant ( HCM reported up to

1 in 500)  Risk of death in 2 years in: - RCM is 50%, - HCM 12%, - DCM 14%

 a 5-year risk for death or transplantation of around 50% for

patients with dilated CM

Complex Pathophysiology

Anatomy:

Histology:

Physiology:

Physiology:

Pathology (cellular level)

Pathology (clinical level)  1- High output HF  2- Low output HF 1- acute decompensation: 2- less acute decompensation:

Pathology (clinical level) 1- High output HF:  frequently seen in infants and young children.  occurs in various congenital lesions with increased

pulmonary blood flow. (eg. Large VSD/PDA/AP window and common art. Trunk)

 ventricular systolic function is typically preserved or even

hyperdynamic with an increased LV chamber dimension.

Clinical feature of high Output HF:  Age of presentation is 2 weeks to 6 months ( High PVR may         

delaye the presentation.

FTT. Sweating.

Pallor.

Tachypnea.

Hyperdynamic pulses.

Rales may be noted, frank pulmonary edema is infrequent.

Gallop rhythm.

Hepatomegaly.

Peripheral edema is invariably absent except in the terminal phase

Pathology (clinical level) 2- Low output HF:  1- acute decompensation:  like in obstruction to LV outflow (HLHS, critical AS, or

severe coarctation of the aorta)

   

decreased pulses.

Pallor. frank circulatory collapse between 2 and 14 days of life .

Tachypnea (either due to excessive pulmonary blood flow, elevated pulmonary venous pressure, or hypoxemia with acidosis) deferent from cyanotic CHD where they are blue but not tachypnic.

Pathology (clinical level) 2- Low output HF:  2- less acute decompensation:  Primary or acquired diseases of the myocardium (such as    

dilated CM or acute myocarditis) can mimic some features of the previous clinical appearance: in addition to: displaced or diffuse cardiac apex. gallop rhythm. soft heart sounds. murmur of mitral regurgitation (all indicate a dilated hypocontractile LV, rather than a primarily obstructed outflow tract).

Cardiomyopathies  The evolution is gradual, allowing for

compensation, until an advanced stage of systolic heart failure, and LV .  Infants with CM may or may not develop heart failure. If they do they will have low output symptoms with FTT.  Teenagers; pallor, fatigue, syncopal events, or unexplained tachycardia ,Abdominal pain and nausea/vomiting.

Case scenario  3 months old boy with FTT , SOB, fatigability  

 

and sweating during feeding.

On exam: weak pulses, large liver, congested chest, tachycardia with gallop rhythm, long systolic murmur at the apex.

X-ray  cardiomegaly.

ECG 

Anomalous origin of the left coronary artery from the pulmonary artery(ALCAPA):  Bland–White–Garland syndrome .  presents between 2 and 6 months of age .  dilated LV, mitral regurgitation.  fairly typical electrocardiographic pattern of an anterior infarct.  q waves in I and aVL , with ST elevation and T wave inversion in lateral leads (LV strain).  Timely recognition allows corrective reimplantation with excellent long-term results.

Resolved post op

ALPACA:

Should we have a common language?  The New York Heart Association (NYHA)

classification is widely used for grading HF in adult patients because of its simplicity in providing a practical assessment of functional limitation.  The Ross Classification was developed for grading HF in infants and younger children.

Is it enough to understand each other?  Both the NYHA and Ross HF scales concentrate

on current symptomatology. Neither of these scales discriminates well among patients with early stages of disease, nor between stable and decompensated stages of illness.  Overt HF symptoms occur late in the disease process, indicating a failure of compensatory mechanisms.

 The ACC/AHA HF guidelines therefore

advocate a HF classification schema that addresses these deficiencies and complements the NYHA scale, The system advocated by the ACC/AHA for HF staging in adults can be readily applied to infants and children as well, with minor modifications

Management:

Initial management:  oxygen, ventilatory assistance, and vascular

access  attempted endotracheal intubation of patients with heart failure is not encourage unless there is a cardiac arrest. (sedation and vagal effects of endotracheal intubation are extremely hazardous in this setting).  High FiO2 bag and mask assistance initially, with noninvasive positive pressure ventilation usually effective.

Pharmacology:  diuretic therapy  should not be indiscriminate or excessive.  Infusion at a lower dosage or oral therapy is

preferable to high-dose intravenous bolus.  Preload dependant disease (advanced pulmonary hypertension, RV failure or restrictive LV physiology, or pulmonary venous obstruction) may worsen in the face of rapid reductions in LV stroke volume which might occur with liberal diuresis.

Inotropic and vasodilators (inodilators)  Indicated in acute phase.  Controversial in long term management ( due to increased     

mortality in adult, however they have ischemic disease that is not in pediatric).

Aim for: 1) increase contractility. (intropy) 2) Decrease vascular resistance. ( afterload) (vasodilator VD) in most cases. ( in cases where coronary perfusion needed you may need vasoconstrictor VC) 3) Decrease oxygen consumption ( and heart rate) (chronotropy) 4) Decrease risk of arrhythmia.

Dopamenergic and adrenergic:  Dopamine. (VC, chrono) rarely used.  Dobutamine (non-selective: VC/VD,

inotropic, chrono, increase VO2).  Epinephrine: (strong VC and inotropy, also has chronotropy effects, increase VO2, risk of arrhythmia.) second line drug.  Norepi: more of VC. Very rarely used in HF

Phosphodiesterase inhibitors:     

Milrinone: VD and weak inotropy.

Long acting.

Can cause arrhythmia and hypotension.

The first choice of therapy in patients with moderate to severe ventricular dysfunction with respiratory or underperfusion symptoms.

Management:

Patients with profound hypotension and poor systolic function:

 Combine milrinone and epinephrine for 48hr  If no improvement consider mechanical

support as a bridge to recovery for some Patients to avoid “forced recruitment” of damaged myocardium, by adrenergic hyperstimulation.

Patients with preserved systolic function:  In patients with symptomatic HF with primarily

    

diastolic function impairment. (eg. Primary RCM (or associated with HCM), acute myocarditis, pericardial tumors, and fibrosis. depend on adequate preload for LV function Gentle diuretic therapy.

Avoid the use of inotropic vasodilatation if possible.

Cardioselective third-generation beta-blocker agents (such as metoprolol) in low dosages.

ICD and HTx ( should be considered).

Acute myocarditis:  Diagnosis need high index of suspicion (better to be wrong         

rather than sorry) Echo is not difficult to learn.

MRI is easier now.

EMB still has a rule in some cases.

Supportive therapy is the most important as majority will recover.

Avoid IS therapy in the acute phase.

If you decide to use IVIG, use it early.

Use antiviral if still positive for virus in EMB or serum.

Go aggressive (ie ECMO) with AFM as they have the best outcome.

Long term HF therapy could be needed for up to two years.

Maintenance therapy:

Mechanical support:  CPAP  Mechanical ventilation  ECMO.  VAD ( Berlin heart, heart mate II).

ECMO:

Berlin heart:

Heartmate II: