Children's Doctor

Cardiology - Winter 2011

A Murmur: Innocent or Not?

Jeffrey Boris, MD

A 4-year-old boy presents to his pediatrician for a routine well-child check. On examination, the physician hears a murmur that he had not previously heard.

What is this murmur, and is it pathologic?

Discussion: The murmur described is a Still’s murmur, which is the most common innocent heart murmur. There are no structural defects associated with this murmur. Innocent, or normal, murmurs are present in approximately 66% of all children and 78% of newborns. They are among the most common reasons for referral to a pediatric cardiologist. It is not known what specifically causes innocent murmurs, although they are thought to be associated with normal turbulence of the blood flowing through the heart or blood vessels.

What is an innocent murmur

There are 6 innocent murmurs (see Table 1), with 4 systolic and 2 continuous murmurs; any solely diastolic murmur should be further evaluated.

In the evaluation of murmurs, it is important to make sure that patients have the following normal findings:

Table 1
Type Age Location Sound Maneuvers
Still's murmur 2-6 years, sometimes
infants, sometimes older
Hockey stick distribution
(apex, LLSB, LMSB, RUSB)
Vibratory, buzzing, "cooing dove," "guitar-string twang," occurring as a systolic ejection murmur Have patient sit up or stand up: murmur should disappear or localize to LLSB
Venous hum 2-6 years, rarely younger RUSB, LUSB, occasionally RMSB Blowing, roaring, wheezing, distant-sounding continuous murmur with diastolic accentuation Lay patient down, compress jugular vein, or turn head: murmur should disappear
Physiologic peripheral pulmonary stenosis Infants 0-6 months Parasternal, precordium, axillae, back Short, soft systolic ejection murmur Murmur sounds the same across the precordium and back, and does not change with position—should be gone by 6 months of age
Carotid bruit 8-14 years Supraclavicular, infraclavicular Somewhat harsh, short, systolic ejection murmur Have patient hyperextend their shoulders: murmur should disappear
Innocent pulmonary systolic murmur 8-14 years LMSB, LUSB Short, soft, grating, systolic ejection murmur Have patient sit or stand up: murmur should disappear or become quieter and localize to LMSB
Mammary souffle Adolescent girls with active breast development, pregnancy (third trimester), or lactating Over the breasts Blowing sound, breath-like, continuous murmur with systolic accentuation and diastolic spill-over Compress breast tissue under the stethoscope to suppress the murmur

How to evaluate a murmur

Patients should be evaluated in the supine and in either the sitting or standing positions. Identifying systole and diastole is important; systole occurs after S1 and diastole occurs after S2. If you are not sure which is which, listen to the heart while palpating the carotid artery; the order of events is S1, carotid upstroke (systole), S2.
Overall, it takes practice to become familiar with these murmurs, and it is often more helpful to listen with someone who is knowledgeable and can guide you. Also, it is not uncommon to have more than 1 innocent murmur. (I have seen patients with 3!) As long as you know which maneuvers to perform to make the murmurs change or disappear, and the remainder of the examination is normal, these patients do not need to be referred for further evaluation.

For primary care providers, it is more important to be familiar with the 6 different innocent murmurs and to be able to discern whether a murmur is innocent or pathologic than to be able to recognize the difference between, say, a VSD and aortic stenosis murmur. If the murmur does not meet the criteria for an innocent murmur, the patient should be referred for further cardiology evaluation.

How to counsel the family:

If the murmur does seem to be an innocent murmur, counseling the family is as important as making the diagnosis. Counseling should include telling the family:

How to refer patients for further cardiology evaluation, or for additional questions:

References and Suggested Readings
Gessner IH. What makes a heart murmur innocent? Pediatr Ann 1997;26(2):82-91.

Hypertrophic Cardiomyopathy: A Family Affair

Beth Kaufman, MD

AM is a 14-year-old healthy girl who presents to her primary care provider for a routine pre-participation physical before starting on her high school lacrosse team. She is athletic and has been engaged in competitive sports teams throughout her childhood. She denies ever having any complaints of chest pains, dizziness, or palpitations, either with or following exercise. She has no significant medical history.

AM has a relevant family history of a 16-year-old brother who collapsed while playing football a year ago, then was successfully resuscitated. On cardiac evaluation, he was found to have hypertrophic cardiomyopathy (HCM). AM also has an 8-year-old sister. Her maternal uncle had an enlarged heart. No other information is available.

AM has a normal physical exam and no evidence of heart murmur at rest. HR is 60 beats per minute; blood pressure is 100/60.

Discussion: AM is at increased risk for having HCM due to a first-degree relative, her brother, having the condition. HCM is estimated to occur in 1 in 500 people in the general population. It is a heterogeneous disorder characterized by abnormal enlargement and disorganization of the heart muscle cells and architecture, as well as abnormal microvasculature of the heart. This combination can result in early heart muscle-cell death and development of replacement scar tissue within the heart.

Symptoms such as dyspnea with exertion may occur due to inefficient blood flow into the heart (diastolic dysfunction), and/or potential for dynamic obstruction of blood flow out the left ventricular outflow tract (subaortic) due to interactions between the hypertrophied septal wall and abnormal movement of the mitral valve leaflets. Arrhythmias can occur regardless of degree of myocardial thickening and/or the presence of left ventricular outflow tract obstruction. They are the cause of sudden cardiac death observed with this disorder.

HCM is caused by a genetic abnormality of the contractile proteins in the heart that can run in families (familial HCM) or occur spontaneously. A form of HCM can also be caused by abnormal deposits in the heart due to metabolic abnormalities. HCM is an unpredictable disease even among family members that carry the same disease-causing gene for the disorder. The degree of cardiac hypertrophy, age at presentation, occurrence of arrhythmias, and disease course can vary greatly between individuals and within families.

Children and adults can be completely asymptomatic, tolerate exercise well, and have a normal physical exam—and still have significant heart abnormalities due to HCM. Unfortunately, sudden cardiac death can be the first presenting sign of HCM, and HCM is the most common cause of these events in the young (<25 years), particularly in competitive athletes. Therefore it is prudent to perform cardiac screening evaluations on individuals who may be at higher risk than the general population, due to family members known to have cardiomyopathy.

Recommendations

If a first-degree family member is identified on history as having cardiomyopathy (of any type except due to coronary artery disease), referral to a pediatric cardiologist for a clinical evaluation with electrocardiogram and echocardiogram to screen for cardiomyopathy is indicated before clearing for competitive sports participation. The Heart Failure Society of America published practice guidelines for the frequency of clinically screening for HCM in first-degree relatives of a patient with HCM. Recommendations are for history, physical exam, electrocardiogram, and echocardiogram every 3 years until age 30, with yearly assessments during puberty, a common time for familial disease to first present.

Therefore, in the case above, the parents and 8-year-old sister also require a cardiac screening evaluation. If there is no evidence of HCM, and parents are older than 30 years, no further screening is recommended. The 8-year-old should have a follow-up cardiac evaluation at age 11 and then annually during puberty. The 14-year-old patient should have annual cardiac evaluations until puberty is complete, then every 3 years (by an adult cardiologist) until age 30.

The above recommendations apply in the majority of HCM cases, when there has not been an identified etiology. Recently, genetic testing for the most common gene mutations associated with familial HCM has become clinically available from several companies. Even in the most severe cases of familial HCM, with many clinically affected family members, a disease-causing gene mutation is identified in <60%. The frequency of a positive test is much less (~30%) for sporadic cases.

However, if a causative gene mutation is identified, genetic testing can help assess the risk of developing HCM in family members without clinical evidence of disease, (such as the patient and younger sibling, in this case). The blood test should initially be performed on the most clearly affected person in a family, who may not be your patient but rather the sibling or parent (the 16-year-old brother with HCM in this case). If a disease-causing mutation is identified on the screening genetic test, then subsequent testing of relatives should be performed to determine the presence or absence of the gene mutation. Genetic counseling of the family by a medical professional with expertise in familial cardiomyopathy prior to performing this evaluation is important.

If HCM is identified, restriction from competitive, high-intensity athletics is recommended, as well as annual evaluation by a cardiologist to assess for development of risk factors associated with increased incidence of sudden cardiac events. This includes: history to assess any syncope, family history of sudden death, echocardiogram or cardiac MRI to determine maximal wall thickness of ventricles, 24-hour ambulatory ECG monitor (Holter monitor) to detect nonsustained or sustained ventricular arrhythmias, and exercise testing to identify abnormal blood pressure response to exercise.

References and Further Readings:
Hershberger RE, et al. Genetic evaluation of cardiomyopathy—A Heart
Failure Society of America practice guideline.
J Cardiac Fail 2009;15:83-97.
Maron BJ. Contemporary insights and strategies for risk stratification and prevention of sudden death in hypertrophic cardiomyopathy.
Circulation 2010;121;445-456.

Hypercholesterolemia in Children

Julie Brothers, MD

A 13-year-old male presents to the lipid clinic for further evaluation of hypercholesterolemia. He had his cholesterol checked at his primary physician’s office due to his father’s history of early heart disease. (Father underwent a quadruple bypass at age 41.) Similarly, his paternal grandfather had a myocardial infarction at age 49. His brother is 15 years old and is currently on a statin medication. His family follows a low-saturated fat diet at home. He buys lunch at school, including cheeseburgers, chicken nuggets, pizza, and cheesesteaks, accompanied by french fries and cookies. Snacks tend to be potato chips or a bowl of cereal. He drinks juice with breakfast and dinner and either chocolate milk or soda at school. He participates in football and baseball. His sedentary time is 2 hours daily on the weekdays and 6 hours on the weekends.

On physical exam, his height is at the 60th percentile and his weight is at the 90th percentile; his BMI is at the 91st percentile, placing him in the overweight category. His blood pressure is 116/74 (50th-90th percentile for both systolic and diastolic), and his pulse is 72 bpm. The rest of his examination is benign. There are no tendon or tuberous xanthomas. He is Tanner stage 2. An average of 2 fasting lipid panels reveal (in mg/dL): total cholesterol (TC) 444, high-density lipoprotein (HDL-c) 64, low-density lipoprotein (LDL-c) 366, and triglycerides 69. Thyroid functions, urinalysis, glucose, insulin, AST/ALT, and CK levels are all within normal limits.

Discussion: Heterozygous familial hypercholesterolemia (HeFH) is the lipid disorder most responsible for the development of premature cardiovascular disease (CVD). It is one of the most common genetic disorders, with an approximately 1:500 prevalence, and is of autosomal dominant inheritance. It is caused by a genetic mutation in the LDL-c receptor or in apolipoprotein B. If untreated, the risk of CVD by the age of 60 years is 80% in males and 45% in females.

Signs and Symptoms of HeFH

Children with HeFH generally have no symptoms or signs of hypercholesterolemia; rarely, they may have tendon or tuberous xanthomas. Further, they traditionally do not fit the profile of someone who is at risk for premature CVD; they often are of normal weight and follow a healthy lifestyle. Unfortunately, with the obesity epidemic, many children with HeFH are also overweight or obese, giving them an additional risk factor for developing premature CVD. Because HeFH is not associated with overweight, it is extremely important to take a good family history.

Diagnosing hypercholesterolemia

Diagnosis is made by obtaining a fasting lipid panel. Normal TC levels are <200 mg/dL and LDL-c levels <110 mg/dL (See Table 1.) Children with HeFH have total cholesterol levels of 270-500 mg/dL and LDL-c of 190-350 mg/dL. A complete evaluation includes ruling out secondary causes of hypercholesterolemia and should include renal and thyroid function tests and a urinalysis. In patients with HeFH, the family should be educated and counseled about the genetic nature of the disorder, and other first- and second-degree relatives should be tested.

Table 1: Plasma Lipid levels in Children (mg/dl)
Category Acceptable Borderline High Low
Total Cholesterol
  • <170
170-199 >200  
LDL-c <110 110-129 >130  
Non HDL-c <123 123-143 >144  
Triglycerides
• 0-9 years
• 10-19 years

<75
<90

75-99
90-129

>100
>130
 
HDL-c >45 35-45   <35

Screening for hypercholesterolemia should occur between the ages of 2 and 10 in children at risk for premature CVD. Recently, recommendations have been expanded to include a larger number of children who are considered at risk. (See Table 2.)

Table 2: Whom to Screen for Hypercholesterolemia
Age >2 years old and:
  • parent with total cholesterol ≥ 240 mg/dl
    • family history + :
      premature CVD in 1st-degree relatives (<55 years males and <65 years females)
    • sudden death
    • unknown (adopted, estranged)
  • congenital heart disease
  • post heart transplantation
  • Kawasaki disease
  • post-cancer therapy
  • chronic inflammatory disease
  • chronic kidney disease
  • overweight or obese
  • sedentary lifestyle
  • smoking or passive smoke exposure
  • hypertension (BP >95th percentile)
  • diabetes/insulin resistance (acanthosis nigricans)
  • medications: retinoic acid, oral contraceptives,
    thiazide diuretics, anticonvulsants

Treatment

The treatment begins with therapeutic lifestyle changes, which include implementing appropriate dietary measures, maintaining appropriate weight, promoting daily physical activity, and, especially in the adolescent population, discouraging tobacco use and encouraging smoking cessation. All children 2 years and over should follow a low-fat (<30% daily calories), low-saturated fat (<10% daily calories) and low-cholesterol (<300 mg daily) diet with at least 5 fruits and vegetables daily. If after 3 months of a low-saturated fat diet the LDL-c remains >130 mg/dL, saturated fat intake should be reduced to <7% of total calories, and dietary cholesterol <200 mg daily. After 6-12 months of dietary and lifestyle therapy, if the child is >10 years (boys) and postmenarchal (girls), a statin medication should be considered if the LDL-c still remains: ≥190 mg/dL (0-1 risk factor), ≥160 mg/dL and a family history of early heart disease, or ≥2 other risk factors (hypertension, overweight, elevated fasting glucose, low physical activity, smoking), or >130 mg/dL if the child has diabetes mellitus.

After 6 months of dietary and lifestyle changes—notably by taking his lunch to school every day and running 2 miles 3 days a week—our patient lost 10 pounds but his cholesterol did not change significantly. He was started on Lipitor 10 mg and was up-titrated over the course of several months to Lipitor 40 mg without any problems. His most recent laboratory studies revealed: TC 221 mg/dL, HDL-c 73mg/dL, LDL-c 138 mg/dL, and TG 51 mg/dL.

Indications for referral to the Lipid Heart Clinic
Entry criteria for children ages 2-17 years

How to refer a patient for further evaluation, or for additional questions on the Lipid Heart Clinic at The Children’s Hospital of Philadelphia:

References and Suggested Readings:
Daniels SR, Greer FR, and the Committee on Nutrition. Lipid screening and cardiovascular health in childhood. Pediatr 2008;122:198-208.
Kavey REW, Allada V, Daniels SR, et al. Cardiovascular risk reduction in high-risk pediatric patients: a scientific statement from the American Heart Association Expert Panel on Population and Prevention Science; the Councils on Cardiovascular Disease in the Young, Epidemiology and Prevention, Nutrition, Physical Activity and Metabolism, High Blood Pressure Research, Cardiovascular Nursing, and the Kidney in Heart Disease; and the Interdisciplinary Working Group on Quality of Care and Outcomes Research. Endorsed by the American Academy of Pediatrics. Circulation 2006;114:2710-2738.
Kwiterovich PO. Recognition and management of dyslipidemia in children and adolescents. J Clin Endocrinol Metab 2008;93:4200–4209.

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