Rae-Ellen W. Kavey

American Heart Association Guidelines for Primary Prevention of Atherosclerotic Cardiovascular Disease Beginning in Childhood

Atherosclerotic cardiovascular disease remains the leading cause of both death and disability in North America. Evidence that most cardiovascular disease is preventable led to development of the American Heart Association’s initial “Guide to the Primary Prevention of Cardiovascular Disease” in 1996 and the updated version in 2002. Those guidelines do not address prevention in children, a group for whom primary prevention should hold the most promise. Emergence of multiple lines of evidence with regard to the importance of known risk factors for atherosclerotic disease in children and young adults has provided the impetus to develop guidelines for primary prevention in this young population. Pathological studies have shown that both the presence and extent of atherosclerotic lesions at autopsy after unexpected death of children and young adults correlate positively and significantly with established risk factors, namely low-density lipoprotein cholesterol, triglycerides, systolic and diastolic blood pressure, body mass index, and presence of cigarette smoking. Findings from the Bogalusa study indicate that as the number of cardiovascular risk factors increases, so does the pathological evidence for atherosclerosis in the aorta and coronary arteries beginning in early childhood. Electron beam computed tomography of coronary artery calcium and increased carotid artery intima-media thickness, an ultrasound measure of carotid artery atherosclerosis, have been evaluated in 29- to 39-year-olds monitored from 4 years of age. Significant risk predictors for coronary artery calcium were obesity and elevated blood pressure in childhood and increased body mass index and dyslipidemia as young adults. Multiple epidemiological studies have demonstrated a disturbing increase in the prevalence of obesity beginning in childhood, with at least 22% of 6- to 17-year-olds diagnosed as overweight. This is a cause for particular concern because of the strong association between obesity and hypertension, dyslipidemia, and type II diabetes mellitus beginning in childhood. Long-term follow-up studies have demonstrated …

Incidence and severity of chronic ventricular dysrhythmias after repair of tetralogy of Fallot.

A group of 72 patients who had undergone surgical correction of tetralogy of Fallot (TF) more than 5 years previously were evaluated for the presence and severity of ventricular dysrhythmias by treadmill exercise testing (TE) and 24-hour ambulatory ECG monitoring (AM). The results of rhythm evaluation were correlated with surgical and clinical data to determine characteristics which identified patients at risk for sudden death. Of the 72 patients, 30 (42%) manifested serious ventricular dysrhythmias on TE and/or AM. Four patients with documented ventricular dysrhythmias had subsequent cardiac arrest; an additional patient was admitted in ventricular tachycardia. Patients with ventricular dysrhythmias (group II) were found to be significantly older than patients without dysrhythmias (group I), both at the time of surgery and at the time of evaluation. The incidence of residual elevation of right ventricular systolic or diastolic pressure on postoperative catheterization did not differ between the two groups of patients. Ventricular extrasystoles on standard ECG were significantly more frequent in patients with documented ventricular dysrhythmias. Chronic serious ventricular dysrhythmias are very common in patients after TF repair. TE and AM should be an integral part of the long-term postoperative assessment in these patients.

Ventricular arrhythmias and biventricular dysfunction after repair of tetralogy of Fallot.

To test the hypothesis that subclinical levels of ventricular dysfunction contribute to the development of ventricular arrhythmias after repair of tetralogy of Fallot, 38 postoperative patients were studied by radionuclide ventriculography and M-mode echocardiography. Eighteen patients (group I) had Lown grade 2 or greater ventricular arrhythmias on ambulatory electrocardiography or treadmill exercise, or both; 20 patients (group II) had no documented ventricular arrhythmias. Radionuclide ventriculograms were performed using technetium -99m-labeled red cells; ejection fractions were derived by computer from multigated images, with normal values being 45% for the right ventricle and 55% for the left ventricle. From M-mode echocardiography, right and left ventricular end-diastolic dimensions were expressed as a ratio, the highest normal value being 0.45. By radionuclide ventriculography, right ventricular ejection fraction was lower for group I (28 +/- 3%) than for group II (31 +/- 2%), but the difference was not significant (p less than 0.10). Left ventricular ejection fraction was significantly lower for group I than for group II (45 +/- 5% versus 55 +/- 3%, p less than 0.05). The echocardiographic right and left ventricular diastolic dimension ratio was elevated in all patients except two in group II; it was significantly greater in group I than in group II (0.84 +/- 0.06 versus 0.63 +/- 0.04, p less than 0.005). This study provides evidence for right ventricular dilation by M-mode echocardiography and for biventricular dysfunction by radionuclide ventriculography in patients who have undergone repair of tetralogy of Fallot.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and Incidence of Hypertension in Adolescent Girls

OBJECTIVE To estimate the prevalence and incidence of hypertension and prehypertension and associated factors in adolescent girls. STUDY DESIGN A total of 2368 girls (49% Caucasian, 51% African-American) aged 9 or 10 years enrolled in the National Heart, Lung, and Blood Institute Growth and Health Study had blood pressure, height, and weight measured at annual visits through age 18 to 19 years. Prevalence and incidence of hypertension and prehypertension were calculated. RESULTS On the basis of 2 visits, hypertension prevalence was approximately 1% to 2% in African-American girls and 0.5% in Caucasian girls. Incidence in 8 years was 5.0% and 2.1%, respectively. Obese girls had higher prevalence (approximately 6-fold higher) and incidence (approximately 2- to 3-fold higher) compared with girls of normal weight. Similar patterns were found for prehypertension, except that prehypertension occurred more in older girls than younger girls. Dietary factors (lower intake of fiber, potassium, magnesium, and calcium, and higher intake of caffeine and calories) were each associated with hypertension incidence (all P<.05). In multivariate analysis, higher body mass index (P<.001) and lower potassium intake (P=.023) were independently associated with incidence of hypertension. CONCLUSIONS Hypertension occurred early in childhood and was related to obesity and other modifiable lifestyle factors. Clinicians should monitor blood pressure during childhood and provide focused diet and physical activity guidance to minimize the development of hypertension.

Procainamide for Rate Control of Postsurgical Junctional Tachycardia

Abstract. This study was conducted to determine the efficacy of procainamide therapy for rapid rate control of postoperative junctional tachycardia (JT). Postoperative JT is one of the most difficult forms of tachycardia to manage. Reported success with a variety of treatments of JT in infants and children has been inconsistent and limited. Rate control using procainamide was achieved in 17 children having rapid JT (heart rate >200 beats/min) between 1986 and 1997. In the first 5 patients (protocol A), following a loading dose of 3 mg/kg over 20 minutes, a continuous procainamide infusion was initiated at a rate of 20 μg/kg/min. The infusion dose was increased in 10 μg/kg steps every 30 minutes to 40–120 μg/kg/min until the heart rate decreased below the target rate of 180 beats/min. In the other 12 patients (protocol B), after a higher loading dose of 10 mg/kg the infusion rate was increased every 10–15 minutes until the heart rate decreased below the target rate of 180 beats/min. Procainamide decreased JT rates in all patients but the response was significantly faster in protocol B. In the patients treated with protocol A, pretreatment JT rates ranged from 203 to 240 (213 ± 17) beats/min and decreased to 195 ± 10 beats/min at 2 hours (p= ns), 186 ± 8.8 at 4 hours (p < 0.02), and 179 ± 8 at 6 hour postinitiation of PA. In protocol B, pretreatment JT rates ranged from 201 to 240 (218 ± 17) beats/min and decreased to 183 ± 20 beats/min at 2 hours (p < 0.001) and 171 ± 12 at 4 hours after starting the procainamide therapy. The mean duration to decrease JT rates below the target rate of 180 beats/min was 3.2 ± 1.1 hours in protocol B compared to 6.4 ± 3.8 hours in protocol A (p < 0.02). Eight of 12 patients in protocol B achieved rate control below the target rate of 180 beats/min within 4 hours despite remaining on significant inotropic support. The procainamide infusion rates to maintain heart rates below 180 beats/min were 40–120 (68.4 ± 22.1) μg/kg/min. No proarrhythmia, bradycardia, or significant hypotension was observed. In this series procainamide provided safe, effective, and rapid rate control of JT occurring in the immediate postoperative period.

Congenital atresia of the left coronary ostium and hypoplasia of the left main coronary artery

The clinical and pathological findings are described in a six-month-old female with an unusual congenital malformation, atresia of the orifice and hypoplasia of the left main coronary artery. The literature is reviewed and the clinical findings are discussed. A comparison has been made with the anatomic findings in true single coronary artery and with the angiographic findings in anomalous origin of the left coronary artery from the main pulmonary artery.

Exaggerated blood pressure response to exercise in children with increased low-density lipoprotein cholesterol.

Arterial vascular responses are characteristically altered with hypercholesterolemia: conduit vessels manifest increased stiffness, and conduit and resistance vessels demonstrate impaired endothelium-dependent dilation and augmented vasoconstriction to neurohumoral stimulation. These changes should be reflected in an exaggerated blood pressure increase in response to exercise. To evaluate this hypothesis, we compared the blood pressure response to treadmill exercise in children with hypercholesterolemia and children with normal lipid levels. In a preliminary retrospective study, 15 hypercholesterolemic boys 10 to 18 years old underwent treadmill exercise testing, and their blood pressure results were compared with those of 32 normolipidemic children in the same age group who had undergone treadmill exercise electively in the same time period. In the second phase, 10 hypercholesterolemic boys and 10 normolipidemic age-matched boys were evaluated prospectively according to the same protocol. Treadmill exercise involved a modified Bruce protocol with heart rate and blood pressure measured before exercise, immediately after exercise, and throughout recovery. Office blood pressures were normal in all children, with no significant difference between groups. With treadmill exercise, all subjects achieved >95% of predicted maximum heart rate and endurance times, maximum oxygen consumption, and maximum respiratory ratio did not differ between groups. Results of the retrospective and prospective groups were similar and were therefore combined. Children with increased low-density lipoprotein (LDL) cholesterol had significantly higher systolic and diastolic blood pressures immediately before treadmill exercise (systolic 120 +/- 13 mm Hg vs 113 +/- 13 mm Hg, p < 0.03; diastolic 68 +/- 8 mm Hg vs 63 +/- 9 mm Hg, p < 0.01). After exercise, blood pressures were again significantly higher in the subjects with high LDL cholesterol (systolic 182 +/- 20 mm Hg vs 160 +/- 23 mm Hg, p < 0.0003; diastolic 77 +/- 12 mm Hg vs 72 +/- 9 mm Hg, p < 0.03). At the end of recovery, systolic blood pressures remained significantly higher in subjects with high LDL cholesterol (120 +/- 9 mm Hg vs 112 +/- 12 mm Hg, p < 0.005). In this study, children with severely increased LDL cholesterol had an exaggerated blood pressure response to exercise when compared with normolipidemic control subjects. The study findings suggest that control of arterial vascular tone may already be altered in children with hypercholesterolemia.

Loss of Sinus Rhythm After Total Cavopulmonary Connection

BACKGROUND Total cavopulmonary connection (TCPC) to repair functional single ventricle involves the sinus node area, in contrast to the Fontan procedure. We compared ECG findings after TCPC and Fontan to evaluate the impact of the cavopulmonary connection on sinus rhythm postoperatively. METHODS AND RESULTS The Fontan group consisted of 17 patients repaired at 7.8 +/- 3.1 years of age (mean +/- SD): 11 for tricuspid or pulmonary atresia (TA/PA) and 6 for single ventricle. The TCPC group consisted of 19 patients repaired at 5.1 +/- 3.2 years of age (mean +/- SD) (P < .001): 9 for TA/PA, 4 for single ventricle, and 6 for hypoplastic left heart syndrome. Mean follow-up after Fontan was 7.7 +/- 2.7 years versus 2.8 +/- 1.6 years for TCPC (P < .001). Preoperative ECGs on all TCPC patients showed sinus rhythm (SR), whereas 16 of 17 Fontan patients had SR and one had nonsinus atrial rhythm (NSAR) since birth. On the first postdischarge ECG, 12 of 19 TCPC patients (63%) were in SR, 4 were in junctional rhythm (JR), and 3 were in NSAR. In comparison, 15 of 17 Fontan patients (88%) were in SR with 1 of 17 in NSAR and 1 in supraventricular tachycardia (P < .05 with chi 2 test). By 2 years postoperatively, only 6 of 15 TCPC patients available for follow-up (40%) were in SR, with 7 of 15 in JR and 2 of 15 in NSAR. By contrast, 13 of 17 Fontan patients (76%) remained in SR, with 1 in NSAR and 3 in JR (P < .05 with chi 2 test). TCPC patients with loss of SR did not differ from other patients in the group in age at repair, preoperative diagnosis, or surgeon performing the procedure. CONCLUSIONS This significant incidence of loss of SR temporally related to surgery suggests that operative compromise of the sinus node area is common with TCPC.

Distinguishing Cardiac Syncope from Vasovagal Syncope in a Referral Population

OBJECTIVE To identify characteristics that distinguish cardiac from vasovagal syncope. STUDY DESIGN We compared characteristics of patients ≤18 years of age with vasovagal and cardiac syncope. Vasovagal syncope subjects represented all patients presenting to outpatient cardiology during a 1-year period for initial evaluation of syncope diagnosed with vasovagal syncope. Cardiac patients were all patients identified by review of diagnoses known to include syncope as a symptom who presented with syncope to the emergency department or inpatient or outpatient cardiology during a 10-year period identified with cardiac etiology. RESULTS There were 89 patients 4-18 years of age with vasovagal syncope and 17 patients 4 months to 17 years of age with cardiac syncope. When we compared patients with cardiac syncope to those with vasovagal syncope, we found that syncope surrounding activity was present in 65% vs 18% (P < .001), family history of cardiac disease or sudden cardiac death was identified in 41% vs 25% (P = .2), abnormal findings on the physical examination supporting cardiac diagnosis were present in 29% vs 0% (P < .001), and abnormal findings on electrocardiograms were found in 76% vs 0%, respectively (P < .001). Screening for cardiac disease using any 1 of these 4 characteristics had a sensitivity of 100% and specificity of 60%. Using this screening rule, we found that 60% of patients with vasovagal syncope would not have been referred to cardiology. CONCLUSIONS Cardiac and vasovagal syncope have dramatic differences in presentation. A screening rule that uses historic features, physical examination findings, and electrocardiogram will accurately separate patients requiring further evaluation for cardiac etiology from those with vasovagal syncope in whom cardiology referral is unnecessary.

Management of High Blood Pressure in Children and Adolescents

Hypertension in childhood is now recognized to be a common and serious problem with a prevalence of 2% to 5%. Large epidemiologic studies have established normative tables for blood pressure beginning in early childhood based on age, gender, and height. Making a diagnosis of hypertension in a child or adolescent identifies an individual at increased risk for early-onset cardiovascular disease who requires specific treatment. Routine blood pressure measurement is recommended at every health care encounter beginning at 3 years of age, but often this is not being accomplished. This measurement is especially important in relation to the obesity epidemic, because approximately one-third of obese children have high blood pressure. Hypertension can be effectively managed with effective lifestyle change and medication when necessary.