The prevalence of arrhythmias, predictors for arrhythmias, and safety of exercise stress testing in children.

Exercise testing is commonly performed in children for evaluation of cardiac disease. Few data exist, however, on the prevalence, types of arrhythmias, predictors for arrhythmias, and safety of exercise testing in children. A retrospective review of all patients ≤21 years undergoing exercise testing at our center from 2008 to 2012 was performed. Patients with clinically relevant arrhythmias were compared to those not experiencing a significant arrhythmia. 1,037 tests were performed in 916 patients. The mean age was 14 ± 4 years, 537 (55 %) were male, 281 (27 %) had congenital heart disease, 178 (17 %) had a history of a prior arrhythmia, and 17 (2 %) had a pacemaker or ICD. 291 (28 %) patients had a rhythm disturbance during the procedure. Clinically important arrhythmias were noted in 34 (3 %) patients and included: 19 (1.8 %) increasing ectopy with exercise, 5 (0.5 %) VT, 5 (0.5 %) second degree AV block, 3 (0.3 %) SVT, and 2 (0.2 %) AFIB. On multivariate logistic regression, variables associated with the development of clinically relevant arrhythmias included severe left ventricular (LV) dysfunction on echo (OR 1.99, CI 1.20-3.30) and prior history of a documented arrhythmia (OR 2.94, CI 1.25-6.88). There were no adverse events related to testing with no patient requiring cardioversion, defibrillation, or acute anti-arrhythmic therapy. A total of 28 % of children developed a rhythm disturbance during exercise testing and 3 % were clinically important. Severe LV dysfunction and a history of documented arrhythmia were associated with the development of a clinically important arrhythmia.

Cardiac troponin I after cardiopulmonary bypass in infants in comparison with older children.

OBJECTIVE: At the present time, there is a trend towards performing open heart surgery at a younger age. Myocardium of infants has been thought to be more vulnerable to cardiopulmonary bypass in comparison with adults. For this study, we evaluated the degree of myocardial injury by measurement of cardiac troponin levels in infants in comparison with older children for similar surgeries. METHODS: Serum was collected before bypass, after bypass, and daily after surgery and serum cardiac troponin I level (micrograms per litre). The demographic data, cardiac diagnoses, types of surgery performed, and peri-operative parameters were collected. RESULTS: Of the 21 children enrolled consecutively, five were infants. Among the 21 patients, four patients had post-operative peak troponin values greater than 100 (three were infants) and all four patients survived and had normal left ventricular systolic function upon discharge echocardiogram. The five infants had peak troponin levels of 222.3, 202, 129, 26.7, and 82.3. The post-operative peak troponin levels were significantly higher in infants (mean 132.5 with a standard deviation of 81.6) than in the older children (mean 40.3 with a standard deviation of 33.4), although there was no significant difference in bypass time, bypass temperature, cross-clamp time, or the length of stay in the intensive care unit between the two age groups. CONCLUSIONS: Higher troponin release is seen in infants in comparison with older children after bypass for similar surgeries. A troponin level greater than 100 after bypass does not necessarily predict death or a severe cardiovascular event in the very young.

Early pleural effusions related to the myocardial injury after open-heart surgery for congenital heart disease.

OBJECTIVES: The degree of effusion immediately after cardiopulmonary bypass (CPB) can vary and may reflect several factors including the degree of myocardial injury. We compared the degree of pleural effusions after CPB to the overall myocardial injury as determined by serum cardiac troponin I (cTnI) levels after elective repair of a variety of congenital heart defects, including univentricular surgeries via cavopulmonary shunts. METHODS: Serum was collected pre-CPB, post-CPB, and daily after that and cTnI level measured. The postoperative pleural effusion was measured each day until the chest tube was removed. Results. The 21 study patients were of average age of 5.5 years (+/-5.6). The duration of chest-tube drainage after open-heart surgery was 4.3 days (+/-3.5) and the amount was 2.4 mL/kg/hour (+/-2.9). For the biventricular repairs, cTnI levels on the postoperative day (POD) 1 best correlated with amount of effusion (n = 16, r = 0.5, P = 0.02) and the average (POD 0-3) cTnI levels with the total duration (n = 16, r = 0.4, P = 0.01) and also the amount (n = 16, r = 0.5, P = 0.02) of effusions. For the cavopulmonary shunts, the post-CBP cTnI level best correlated with the duration (n = 5, r = 0.8, P = 0.02) and amount (n = 5, r = 0.9, P = 0.02) of effusions. A cTnI level on the first postoperative day >or=15 microg/L was associated with effusions >2 days (sensitivity of 81% and specificity of 80%). CONCLUSION: We found that higher the cTnI released, especially >or=15 microg/L, longer the duration and greater the amount of early pleural effusions for a variety of congenital heart surgeries including cavopulmonary shunts. A number of factors may lead to excessive pleural effusions and the degree of myocardial injury may be one of them.

Atherosclerosis in survivors of Kawasaki disease.

OBJECTIVES: To test the hypothesis that long-term survivors of low-risk Kawasaki disease (KD) have ongoing vascular inflammation and dysfunction and a higher risk of accelerated atherosclerosis than healthy control subjects. STUDY DESIGN: Twenty-eight patients with KD (7-20 years after acute illness) and 27 age-matched healthy control subjects were examined for medical and dietary history, serum markers of atherosclerotic risk and inflammation, carotid intimal-medial thickness (CIMT) with vascular ultrasound scanning and arterial stiffness with applanation tonometry. RESULTS: Patients and control subjects were similar in age, sex, body mass index, waist-to-hip ratio, blood pressure, cigarette smoking, family history, diet, high-density lipoprotein cholesterol level, lipoprotein (a) level, homocysteine level, glucose level, insulin level, CIMT, arterial stiffness, C-reactive protein level, and inflammatory cytokine level. Levels of total cholesterol and apolipoprotein B were significantly higher in patients with KD than in control subjects. CONCLUSIONS: There was no evidence of increased atherosclerosis. Small but significant differences in cholesterol and apolipoprotein B levels could suggest increased future risk for atherosclerosis and warrant further study.

Endovascular stent implantation in the pulmonary arteries of infants and children without the use of a long vascular sheath.

Endovascular stent implantation for pulmonary artery stenosis requires the use of a long, large-bore vascular sheath to insure precise implantation without embolization or malposition. A long vascular sheath may be difficult to position and usage may be associated with vascular compromise and/or hemodynamic embarrassment, especially in infants and small children. We report a new technique for pulmonary artery endovascular stent implantation without the use of a long sheath. From December 2000 to May 2001, 10 patients underwent implantation of 13 Palmaz Corinthian premounted biliary transhepatic stents for pulmonary artery stenosis. Median age was 0.8 years (range, 0.5-18.5) and median weight was 11.8 kg (range, 4.6-65). Patient diagnoses were tetralogy of Fallot (five), double outlet right ventricle (three), branch peripheral pulmonary artery stenosis (two), single ventricle s/p cavopulmonary shunt (one), and truncus arteriosus (one). All Palmaz Corinthian stents were delivered uncovered on Cordis Opta LP balloon catheters via short sheaths (6-7 Fr); super-stiff guidewires were not always necessary. These stents, with a maximal expanded diameter of 12 mm, were placed for peripheral pulmonary artery stenosis as a definitive procedure or at the pulmonary artery bifurcation in patients who were expected to undergo future open heart surgery. The stents were initially implanted on 4, 6, or 8 mm balloon catheters and further expanded if needed. Stents were placed in the right pulmonary artery alone in three patients, left pulmonary artery alone in four patients, and side-by-side stents were implanted simultaneously in three patients. All thirteen stents were implanted successfully in the desired location without stent malposition or embolization. Mean angiographic diameter increased from 2.5 +/- 1.5 to 5.7 +/- 1.4 mm (P < 0.01) and peak systolic ejection gradients decreased from 44 +/- 22 to 14 +/- 11.6 mm Hg (P < 0.01). The uncovered delivery of the premounted Palmaz Corinthian stent allowed for precise and safe endovascular stent implantation without the hemodynamic and technical problems associated with long vascular sheath usage. This technique is useful for the palliation of proximal pulmonary artery stenosis and is effective definitive treatment for peripheral pulmonary artery stenosis in small infants and children.