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Pediatric Acquired Heart Diseases


ACQUIRED  CARDIAC ILLNESSES IN CHILDREN

Dr.M.Zulfikar Ahamed, Professor of Pediatric Cardiology,SAT Hospital, Govt Medical College ,Thiruvananthapuram

1.       Are Cardiomyopathies common in children?

          They are not uncommon. In fact the second commonest acquired heart diseases among cardiac admissions in our hospital are Cardiomyopathies – dilated Cardiomyopathies.

2.       Which Cardiomyopathies present in childhood?

          Commonest one is dilated Cardiomyopathy (DCM). Occasionally HCM will manifest. Rarely children can have Restrictive Cardiomyopathy (RCM).

3.       How does one treat DCM?

            Treatment is symptomatic. The aim is to control CHF, improve symptoms and improve survival. A brief of management strategy is given below; incorporating NYHA status and drugs

Drugs

FC  I

FC  II

FC   III

FC  IV

ACE inhibitors

+

+

+

+

Digoxin

-

+

+

+

Diuretics

-

+

+

+

b-Blockers

-

+

+

+

Spironolactone

-

+

+

+

Asymptomatic LV dysfunction in DCM is offered Ace inhibitors. Most symptomatic DCM will receive Digoxin, diuretics, ace inhibitors, b-blockers and perhaps Spironolactone.

          These drugs are continued indefinitely and removed one by one once child becomes asymptomatic, cardiac status becomes normal (CXR, ECG and echocardiogram). 6-12 months after all parameters reach normal values one can start reducing / removing drugs.

DRUGS IN DCM – SURVIVAL BENEFIT

Drugs

Symptom relief

Survival benefit

Ace inhibitors

++

+++

Digoxin

++

?

Diuretics

+++

-

b-blockers

++

++

Spironolactone

+

+

 

4.       How does one treat Hypertrophic Cardiomyopathy in (HCM) children?

NYHA I       

Use of drugs is debated. However many prescribe b-blockers to this subset.

NYHA II.  III

          Either b-blockers (Propranolol) or calcium channel blockers (Verapamil) is used and continued indefinitely. Diuretics are used cautiously. Digoxin is not indicated.

NYHA IV

          May need additional diuretics. Digoxin may be used if LV dysfunction exists.

In addition, children with HCM with high risk factors for sudden cardiac death (SCD) are offered amiodarone or implantable cardioverter – defibrillator.

5.       Will HCM require surgical intervention?

          Only if there is severe LVOT obstruction and / or MR. LVOT obstruction can be removed by myectomy and mitral valve can be replaced. Alternatively alcohol ablation of first septal perforator can be done to achieve a controlled myocardial infarction of basal obstructing interventricular septum, causing it to become thin and non obstructive.

6.       Which are the common viruses that cause myocarditis?

          Most important is Coxsackie B viruses, followed by Adeno virus and parvo virus .

7.       What is CAR concept?

          It means that myocardial cells may have a specific common receptor for either Coxsackie virus or Adeno virus which make myocardium very attractive target for either Coxsackie or Adeno virus.

8.       What are Dallas criteria?

          It is a set of diagnostic criteria set by a group of cardiac pathologists for viral myocarditis which / who met in Dallas, USA. This was in 1986; the criteria were published in 1987.

9.       What are they ?

          These are based on Endomyocardial biopsy of a suspected viral myocarditis.

a.       Active myocarditis -        Inflammation + cell death.

b.       Border line       “              -        Inflammation alone

c.       Normal                            -        No cell death / inflammation

in   a. Follow up biopsy

     a.  Ongoing myocarditis        -        inflammation + cell death

     b.  Resolving myocarditis       -        Inflammation alone

     c.  Resolved       “                 -        No cell death / inflammation

10.     What is pre hypertension in children ?

          Normal BP in children is when BP values are below 90th centiles for age, gender and height. If values are above 95th centile, it is hypertension. Originally values between 90th centile and 95th centle were called high normal. These values are now called as pre hypertension. It underlines the importance of active intervention in this subset without medications. Lifestyle modification is offered to this subset of children and adolescents.

11.     What is Metabolic syndrome in children and adolescent?

          It is a cluster of metabolic abnormalities which are present in them. There are five manifestations. If 3/5 is present, the person is deemed to have metabolic syndrome (MS)

They are

1.                 Obesity (based on BMI or Waist hip circumference)

2.                 Insulin resistance (based of plasma glucose or plasma insulin levels)

3.                 High BP (> 90th centile for age, gender and height)

4.                 Low HDL cholesterol (< 40 mgm/dl)

5.                 High Triglycerides (> 150 mgm/dl)

12.     Does  MS exist in our population?

          Yes. It may exist in approximately 15-20% of adult population and 1-2% of child and adolescent population.

13.     How does one measure or define obesity?

          They are different methods.

a.                 Based on BMI

b.                 Based on waist circumference

BMI based measurements can be based on

i.                    IOTF values (International Obesity Task Force)

ii.                  CDC values (Center for Disease Control, USA)

 

CDC Values:

          < 5th centile for age          -        Under weight

          5th – 85 centile for age      -        Normal

          85-95th centile                  -        Over weight

          > 95the centile                 -        Obesity

14.     What is Barker hypothesis?

            This hypothesis, which was postulated in 1987 states that low birth weight (LBW) babies have a higher propensity to develop insulin resistance, dyslipidemia, obesity and cardiovascular diseases (CVD) in later adult life. This hypothesis may be operating in Asians including Indians where the percentage of LBW is very high – as high as 27%. This could explain the unusual high prevalence of CVD in Indians

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