Congestive Heart Failure (CHF) – Treatment, Management

CARDIAC FAILURE

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Last Updated : 5/11/2016
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Valerie Schroeder
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Treatment Approaches to Heart Failure Based upon Cardiac Etiology
Expert panels have developed treatment guidelines based upon the weight of scientific evidence as well as clinical expertise (4, 5). It is helpful to divide patients into one of two groups based upon the presence of absence of structural heart disease (Table 4).
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1) Children with Structural Heart Disease:

In children with congenital heart disease, symptoms are usually a consequence of either intracardiac shunts (volume over load) or blood flow obstruction (pressure overload) or a combination of the two.

Volume overload- (excessive preload )

This group includes either moderate to large left to right intracardiac shunting (septal defects) or moderate to severe heart valve insufficiency. In newborns with intra-cardiac shunts, symptoms usually become apparent within the first few months of life as pulmonary vascular resistance falls. The key finding is progressive respiratory distress. Infants have exacerbated symptoms during feeds during which excessive calories are expended resulting in poor weight gain. There is rise in renin, aldosterone, brain natriuretic peptide (BNP) and cytokines. These factors appear to contribute to fluid retention, tachycardia, failure to thrive, and cardiac dilation (3-6).
The treatment goal for volume overload (Table 5) is pre-load reduction using loop diuretics (furosemide, 0.5- 2 mg/kg/dose PO Q6-12h) and aggressive nutritional therapy (120-130kcal/kg/day). Thiazide diuretics can be co-administered with loop diuretics to obtain a synergistic effect (if a loop diuretic alone in ineffective). Digoxin (dose schedule varies by age) may be used in combination with the former agents but is rarely effective when used alone. Aldosterone antagonists are used in combination with the aforementioned therapies, as these agents appear to modulate certain aldosterone-mediated activities (myocardial fibrosis, remodeling, and free radical production).
Pressure overload- (excessive afterload)
Pressure overload is usually a result of severe semilunar valve disease or hypertension. In the most severe cases, the left ventricular cardiac output becomes compromised and the child may become acidotic and develop shock. Subendocardial ischemia may lead to myocardial dysfunction. Very little known about the expression of systemic modulators in pressure overload. It is not clear if BNP is a helpful marker in these cases (3-6, 13).

Treatment for pressure overload involves relief of obstruction and support of cardiac function (inotropes, and vasodilators such as Nipride or Milrinone- 0.3-1 mcg/kg/min).


Table 4. Pathophysiology of Heart Failure Based upon Lesion
Presence of structural heart disease

Volume overload (usually no pump dysfunction)
         Left to right shunting
             Moderate to large ventricular septal defect
             Large atrial septal defect
             Large patent ductus arteriosus
         Heart valve insufficiency
             Semilunar valve insufficiency
             Atrioventricular valve insufficiency
Pressure overload (possible pump dysfunction)
             Left sided blood flow obstruction, aortic valve stenosis, coarctation
             Right sided blood flow obstruction, pulmonary valve stenosis
             Complex congenital heart disease, single ventricle physiology

Absence of structural heart disease (pump dysfunction systolic and or diastolic)

Primary cardiomyopathy
         Dilated
         Hypertrophic
         Restrictive
Secondary cardiomyopathy
         Tachyarrhythmia
         Drugs/toxins
         Infectious/metabolic
         Myocarditis



Table 5. Summary of Treatment Options for Pediatric Heart Failure Based upon Pathophysiology
I Heart Failure with congenital heart disease
         Volume overload
             Diuretics (drug class)
                  Loop- Lasix (Furosemide)
                  Thiazide- Diuril, may be used in combination with Lasix if refractory to Lasix alone
                  Potassium sparing, aldosterone receptor antagonist, Spironolactone
             Digoxin (Digitalis) may have anti-sympathomimetic effects
             Surgical or catheter intervention for definitive therapy

         Pressure overload
             Surgical or catheter intervention for definitive therapy
             Inotropic support for cardiac dysfunction if present
             Prostaglandin (newborns with ductal dependent disease)

II Heart Failure with no structural heart disease
         Systolic dysfunction
                  Digoxin, inotropic and anti-sympathomimetic effects
                  ACE inhibitors (Captopril, Enalapril), afterload reduction, blocks aspects or renin angiotensin system
                  Beta-blockers (Carvedilol, Metoprolol), anti-sympathomimetic effects
                  Mechanical support/transplantation
                  Anticoagulation (Salicylates), intracardiac thrombosis
                  IVIG (controversial treatment for myocarditis)

         Diastolic dysfunction
                  Beta blocker- improve ventricular filling, decrease afterload, arrhythmia control
                  Diuretics- decrease ventricular volume
                  ACE inhibitors- reduce neurohumoral activation
                  Transplantation

         Arrhythmia
                  Cardioversion (medical/electrical)
                  Pacemaker
                  Radiofrequency ablation



Complex heart disease-

Infants with complex congenital heart disease may present with combined volume and pressure overload (hypoplastic left heart syndrome). These infants are frequently cyanotic and are dependent upon the ductal arteriosus to sustain adequate pulmonary or systemic circulation. Consequently, prostaglandins (0.05-0.1 mcg/kg/min) are required. Judicious use of diuretics can help with pulmonary volume overload. Low dose inotropes (Dopamine 5-10 mcg/kg/min) and afterload reduction (Milrinone) may help support systolic perfusion while awaiting an intervention (3-6, 13).
2) Children without Structural Heart Disease, Examples include:
Rhythm disorders : complete heart block, supraventricular tachycardia, ventricular tachycardia

Systolic dysfunction, myocarditis , dilated cardiomyopathy/metabolic disease, malnutrition, ischemia

Diastolic dysfunction: hypertrophic or restrictive cardiomyopathy, pericardial disease

The goals of medical therapy include reductions in preload and afterload but also require enhancement of contractility and oxygen delivery (blood, iron supplements, oxygen). (3-6, 13).
How aggressive therapy should be largely depends upon the severity at presentation. Severe acute heart failure may present as shock (hypotension, poor peripheral perfusion, thready pulse) decreased urine output. Fatigue, abdominal pain, nausea/vomiting, exercise intolerance, dizziness, or syncope are seen in older children. Renal and liver dysfunction may be present, as well as a decreased level of consciousness. Intensive care admission with advanced monitoring and/or mechanical support versus referral to an experienced heart failure center is advised (3-6, 11.13).

Initially, airway, breathing, and circulation should be supported. Oxygen could be provided for comfort (except with volume overload shunts that may increase pulmonary congestion). Initial laboratory testing may include blood culture; and empiric antibiotic therapy for infants along with a complete metabolic profile, lactate, BNP and troponin I. Sedimentation rates or C-reactive proteins may help support a diagnosis of pericarditis or myocarditis. Mixed venous oxygen saturations (Sv02, normal 60-80%) are to assess cardiac output. Older children may require the placement of a central venous or pulmonary artery catheter to monitor venous pressure and cardiac output. Fluid balance should be followed daily until patients are stabilized (3-6,13). Urine output, pulses, capillary refill, and perfusion are useful markers of hydration status.
Management of low cardiac output can be initiated by using a dopamine infusion of 5-10 mcg/kg/min and Milrinone (0.3-1 mcg/kg/min). Acidosis can be corrected with the administration of fluid and/or bicarbonate. Calcium should be replaced when hypocalcemia is documented. Diuresis is achieved with loop diuretics (furosemide) but additional diuretics such as thiazides with alternative targets of nephron function could also be added. Nitrates (nitroprusside) may be useful in patients with elevated pulmonary capillary wedge pressure and pulmonary congestion. Tachyarrhythmias, (usually supraventricular tachyarrhythmia) and complete heart block require prompt pharmacologic or electrical cardioversion.

What outpatient treatments are best remain controversial. Afterload reduction (ACE inhibitor) is indicated in the presence of left ventricular dysfunction and left-sided regurgitant lesions. An angiotensin receptor blocker (ARB), such as losartan, may be used if ACE inhibitor side effects (rash, cough) are not tolerated (3-6, 13). Low-dose furosemide (1 mg/kg/dose PO bid) may be added to decrease pre-load and increased to 2 mg/kg/dose orally 3 times daily as needed. A second agent, such as Diuril or Metolazone, can be provided as intermittent doses to treat mild exacerbations. Electrolytes should be monitored (alkalosis, hyponatremia, hypokalemia) if multiple diuretics are used simultaneously for longer periods.
Digoxin is commonly used if systolic dysfunction is present and it may also decrease cardiac autonomic tone. Beta blocker use is controversial but considered reasonable for left but not right ventricular systolic dysfunction (carvedilol, 3-6, 13).
Other Treatment Considerations for Heart Failure
Anemia
Anemia increases cardiac output and oxygen consumption. Correcting the iron status and or transfusions may result in clinical significant improvement (15).

Nutrition
During infancy, enhanced caloric content (100-130mg/kg/day) with or without nasogastric or gastrostomy feedings may be necessary (3-6).

Thrombus formation- severe systolic dysfunction
Aspirin (low dose) is used as prophylaxis although with severe dysfunction, Warfarin may be considered (3-6).

Genetic testing
Genetic testing for cardiomyopathy can diagnose a cause in 50% of cases (5). Early testing may lead to immediate treatment versus waiting for disease to become clinically evident. This information is also useful for family planning.

References

Contributor Information and Disclosures Valerie Schroeder
Pediatric Cardiology Associate Professor
University of Kansas Medical Center Department of Pediatrics
3901 Rainbow Blvd, Kansas City, KS 66160


First Created : 1/12/2001
Last Updated : 5/11/2016
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Last Updated : 5/11/2016
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