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Arrhythmias and Conduction Defects as Presenting Symptoms of Fatty Acid Oxidation Disorders in Children

BACKGROUND The clinical manifestations of inherited disorders of fatty acid oxidation vary according to the enzymatic defect. They may present as isolated cardiomyopathy, sudden death, progressive skeletal myopathy, or hepatic failure. Arrhythmia is an unusual presenting symptom of fatty acid oxidation deficiencies. METHODS AND RESULTS Over a period of 25 years, 107 patients were diagnosed with an inherited fatty acid oxidation disorder. Arrhythmia was the predominant presenting symptom in 24 cases. These 24 cases included 15 ventricular tachycardias, 4 atrial tachycardias, 4 sinus node dysfunctions with episodes of atrial tachycardia, 6 atrioventricular blocks, and 4 left bundle-branch blocks in newborn infants. Conduction disorders and atrial tachycardias were observed in patients with defects of long-chain fatty acid transport across the inner mitochondrial membrane (carnitine palmitoyl transferase type II deficiency and carnitine acylcarnitine translocase deficiency) and in patients with trifunctional protein deficiency. Ventricular tachycardias were observed in patients with any type of fatty acid oxidation deficiency. Arrhythmias were absent in patients with primary carnitine carrier, carnitine palmitoyl transferase I, and medium chain acyl coenzyme A dehydrogenase deficiencies. CONCLUSIONS The accumulation of arrhythmogenic intermediary metabolites of fatty acids, such as long-chain acylcarnitines, may be responsible for arrhythmias. Inborn errors of fatty acid oxidation should be considered in unexplained sudden death or near-miss in infants and in infants with conduction defects or ventricular tachycardia. Diagnosis can be easily ascertained by an acylcarnitine profile from blood spots on filter paper.

Coronary Artery Obstruction After the Arterial Switch Operation for Transposition of the Great Arteries in Newborns

OBJECTIVES We sought to describe a large series of coronary artery obstructions after the arterial switch operation for transposition of the great arteries and to discuss their clinical implications. BACKGROUND Aortic root angiography and myocardial perfusion imaging yield ambiguous results regarding the fate of the coronary artery anastomoses after the arterial switch operation. Late death related to coronary artery obstruction and growth of the translocated coronary arteries are of major concern in these patients. METHODS Selective coronary artery angiography was performed prospectively in a total of 165 children. RESULTS A total of 12 coronary occlusions, 8 major stenoses, 6 minor stenoses of the left ostium and 4 stretchings of one coronary artery were identified. Obstructions were more frequent in types D and E (p < 0.001) of the Yacoub and Radley-Smith classification. Coronary obstruction was documented in all patients with electrocardiographic and ultrasound evidence of myocardial ischemia at time of study. Early postoperative ischemia did not predict coronary artery lesion if the patient had fully recovered. Persistent or delayed myocardial ischemia was highly predictive of coronary artery lesions. The incidence of coronary artery obstruction was very high (11 of 35) in patients operated on by a rapidly abandoned technique of single-orifice reimplantation of both coronary artery ostia. CONCLUSIONS Selective coronary angiography is the most accurate means to assess coronary artery obstruction after the arterial switch operation. Precise diagnosis of coronary artery lesions after this operation will help to elucidate the pathogenesis, develop adequate therapeutic strategies and might indicate how to prevent coronary complications after operation.

Quality of life and perceived health status in surviving adults with univentricular heart

OBJECTIVE To evaluate the quality of life in patients with univentricular heart and to determine the impact of sociodemographic and clinical characteristics. DESIGN AND SETTING Retrospective, cross sectional study conducted in a regional paediatric cardiology centre. PATIENTS The health records of 89 survivors with univentricular heart (median age 21 years; range 17–49 years) were reviewed. Sixty seven answered the Duke questionnaire. Sociodemographic and clinical variables were similar in the responders and non-responders. The impact of sociodemographic and clinical variables on individual Dukes measures was assessed. RESULTS The Duke scores of adults with univentricular heart were similar to the normal population. Cyanosis predicted a worse score for physical (p = 0.05) and perceived health measures (p = 0.02). A higher educational level predicted a better score for physical (p = 0.004), mental (p = 0.01), and general health measures (p = 0.02). Orthopaedic problems worsened the social score (p = 0.05). Psychosocial problems worsened the pain score (p = 0.04). In comparison with the other anatomical types, mitral atresia worsened the perceived health score (p = 0.02). Patients younger than 23 years scored better for almost all health and dysfunction measures. CONCLUSIONS Despite repeated interventions and other disease related everyday stresses, a selected group of adults with univentricular heart had a satisfying quality of life.

Fate of pulmonary artery after anatomic correction of simple transposition of great arteries in newborn infants.

From April 1984 to April 1987, surgical anatomic correction was performed in 86 newborn infants, 2-23 days old (6.8 +/- 3.6 days, mean +/- SD) with simple transposition of the great arteries. In all patients, the pulmonary artery was reconstructed by end-to-end anastomosis according to the Lecompte maneuver, including eight patients with side-by-side position of the great arteries. Three different approaches were used. In the first 10 patients (group 1, six survivors), two separate patches of preserved tanned pericardium were used to reconstruct the pulmonary artery, whereas in the next 15 patients (group 2, 13 survivors), a single patch of the same material was used, and in the last 61 patients (group 3, 56 survivors), surgery was performed with a single patch of fresh autologous pericardium. Among the 75 survivors, 68 (including six in group 1, 12 in group 2, and 50 in group 3) were followed serially for at least 6 months (6-48 months, 26 +/- 9 months) with sequential noninvasive evaluations. At follow-up, all were asymptomatic with normal growth. Two patients with severe pulmonary artery stenosis (group 1) were successfully reoperated on. Four infants with moderate pulmonary artery stenosis have been followed medically and have had stable right ventricular pressures. The last 62 patients have normal or near-normal right ventricular pressures. The spatial relation of the great arteries did not affect the quality of the results. Group 1 had clearly the worst results.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics and Results of Epicardial Pacing in Neonates and Infants

The results of epicardial pacing in infants with isolated congenital complete atrioventricular block (CAVB) are reported. Thirty‐four patients, aged 1 day to 20 months (22 patients < 1 month), were paced between 1988 and 1998. Thirty had bradycardia < 50 beats/min with symptoms in 12 patients, and 4 patients were paced because of associated ventricular ectopy or prolonged QT interval. In thirty cases, the electrodes were implanted through a left thoracotomy and connected to an abdominal generator; in four, the sub‐xyphoid approach was preferred. Twenty‐two children had dual chamber units. There was no operative death, but three patients died later of cardiomyopathy. Seven infants were reoperated for electrode displacement, infection, exit block, and pacemaker sensitivity. Chronic ventricular thresholds ranged from 0.3 to 2 V except in one case (4 V) and proper atrial sensing was lost in two cases. All children are doing well and the generator has lasted at least 5 years in 16 cases. In conclusion, epicardial pacing in infants with CAVB can be done with satisfactory results. There was no mortality in relation with pacing and thresholds have improved with the use of steroid‐eluting electrodes. The deep location of the generator prevents cutaneous erosion and allows implantation of large units with a longer life duration.

Progressive left main coronary artery obstruction leading to myocardial infarction in a child with Williams syndrome.

Abstract We report a 3-year-old child with Williams syndrome in whom the first vascular feature of the syndrome was a myocardial infarction related to the occlusion of the left main coronary artery trunk. This coronary artery occlusion was not associated with supravalvular aortic stenosis. Conclusion This report emphazises that acute vascular events related to systemic artery anomalies may reveal Williams syndrome.

Anomalous left coronary artery arising from the pulmonary artery in infancy: is early operation better?

From January 1975 to January 1987, 21 consecutive infants aged less than six months (mean (SD) 2.6 (1.2] were admitted with anomalous origin of the left coronary artery from the pulmonary artery. In the first 12 patients, who were seen up to 1982, operation was performed after the age of one year (mean (SD) 29 (29) months) (group 1). The next nine infants, seen from 1983 to 1987, had their operations within a few weeks of the onset of symptoms (mean (SD) age 4.8 (1.4) months) (group 2). In group 2 the left coronary artery was relocated into the aorta, whereas in group 1 there was additional resection of the left ventricular wall or mitral valvoplasty or both. At presentation there were no differences in age, clinical condition, heart enlargement, and echocardiographic left ventricular dysfunction between groups 1 and 2. Seven of the 12 patients in group 1 died, five while they were awaiting operation (three died suddenly at home) and two at operation. The five survivors are doing well 6.4 (3.1) years after operation with normal left ventricular function which improved slowly over several months after operation. Two of the nine patients in group 2 died; both deaths occurred at or soon after operation. The seven survivors are doing well 1.8 (0.9) years after operation. In three, left ventricular function recovered within three weeks; and there was even partial or total regression of the Q waves in the supposedly necrotic areas. In the remaining four the pattern of improvement in left ventricular function resembled that in group 1. Operation should be undertaken early in infants with anomalous left coronary artery arising from the pulmonary artery because the procedure is relatively safe, prevents a high natural mortality, and offers a better chance of a faster recovery of left ventricular function.

Total cavopulmonary and atriopulmonary connections are associated with reduced heart rate variability

AIM To determine whether cavopulmonary connections are associated with abnormalities of heart rate variability. METHODS Heart rate variability was studied by 24 hour Holter monitoring in 39 patients (mean (SD) age 12.2 (4.1) years) who underwent cavopulmonary connection operations (partial in 12, total in 13, and atriopulmonary in 14). Two control groups were used: 18 healthy children (11.1 (2.5) years) and 16 patients (11.7 (4.3) years) undergoing cardiovascular surgery for biventricular repair of congenital heart disease. All patients were in sinus rhythm and had normal left ventricular function. Four time domain indices were calculated: mean duration of RR intervals (RR), standard deviation of all RR intervals (SD), square root of the mean squared differences of successive RR intervals (r-MSSD), and percentage differences of successive RR intervals of > 50 ms duration (pNN50). Four frequency domain indices were calculated: total power (TP), low frequency (LF), high frequency (HF), and the LF:HF ratio. RESULTS Heart rate variability indices were identical in the two control groups. Significantly reduced heart rate variability was found in patients with total cavopulmonary connections and atriopulmonary connections compared with the two control groups. In patients with partial cavopulmonary connections, heart rate variability was reduced compared with healthy controls. No differences in heart rate variability could be related to clinical status (New York Heart Association functional class), number of surgical interventions, or presence of right atrial enlargement. CONCLUSIONS Patients with cavopulmonary connections have significantly reduced heart rate variability and a particularly low vagal drive.

Amiodarone as Treatment for Atriai Tachycardias After Surgery

Atriai flutter, including all types of postoperative atrial tachycardias, is the one with the highest risk of late sudden death. Thus, late postoperative atrial tachycardias must be suppressed and all patients should be permanently treated after a first episode of atrial flutter. Daily oral doses of 200‐250 mg/m2 amiodarone were found to be highly effective and well tolerated in young patients. However, in older patients and after long‐term therapy, its use is restricted by adverse side‐effects. In these cases, association of lower doses of antiarrhyth‐mic agents, including amiodarone, may be effective and well tolerated. The use of other therapeutic options such as radiofrequency ablation should also be considered in older patients having drug‐refractory postoperative atrial flutter.

Patients Operated for Tetralogy of Fallot and with Non-Sustained Ventricular Tachycardia Have Reduced Heart Rate Variability

Background:To study heart rate variability (HRV) in patients operated for tetralogy of Fallot (ToF) and to identify any correlation between HRV and ventricular tachycardia (VT).Patients and Methods:We studied HRV in 23 consecutive patients operated for ToF (mean age 14 ± 6.6 years; mean follow-up 10.6 ± 5.2 years). Seven patients had non-sustained VT on Holter monitoring. Two control groups were included: 18 healthy subjects and 15 patients operated for other congenital heart disease. There were no differences in age, age at surgery (in the operated groups), follow-up, and mean heart rate between the three groups. Four time and four frequency domain indices were calculated: mean duration of RR intervals, standard deviation of all RR intervals (SD), square root of the mean squared differences of successive RR intervals (r-MSSD), percent of differences between adjacent RR intervals (pNN50), total power (TP), low frequency (LF), high frequency (HF), and LF/HF ratio.Results:HRV indices were identical in the two control groups but were significantly reduced in patients with ToF. Within the patients who had been operated on for ToF, HRV indices were significantly lower in the seven with non-sustained VT than in those without arrhythmias: SD (95 ± 15 vs. 135 ± 54 ms; p = 0.01), r-MSSD (26 ± 9 vs. 45 ± 20 ms; p = 0.03) , pNN50 (4.4 ± 3.4 vs. 16.5 ± 12.5%; p = 0.001) and HF (111 ± 97 vs. 352 ± 291 ms2; p = 0.009). Using stepwise multivariate regression analysis, pNN50, age at surgery, degree of pulmonary regurgitation and higher right/left ventricular ratio were independent predictive variables for VT (p < 0.0001; r2 = 0.85).Conclusions:ToF patients, particularly those with ventricular arrhythmias, have significant impairment of sympatho-vagal balance, characterized by a reduction of vagal drive.Hintergrund:Die Herzfrequenzvariabilität (HRV) und etwaige Zusammenhänge mit dem Auftreten von Kammertachykardien (VT) wurden bei Patienten mit operativ versorgter Fallot-Tetralogie (ToF) untersucht.Patienten und Methoden:Die HRV wurde bei 23 konsekutiven Patienten (mittleres Alter 14 ± 6,6 Jahre; mittlere Nachuntersuchungszeit 10,6 ± 5,2 Jahre), die sich einer operativen Fallot-Korrektur unterzogen hatten, analysiert. Sieben Patienten hatten nicht anhaltende Kammertachykardien in Langzeit-Ekg-Aufzeichnungen. Zwei Kontrollgruppen wurden eingeschlossen: 18 Gesunde und 15 Patienten , die aufgrund einer anderen angeborenen Herzerkrankung operiert worden waren. Es fanden sich keine Unterschiede bezüglich des Alters, des Operationsalters (in den operativ versorgten Gruppen), der Nachuntersuchungsdauer und der durchschnittlichen Herzfrequenz zwischen den drei Gruppen. Jeweils vier Zeit- und Frequenzindizes wurden erfasst: die mittlere Dauer der RR-Abstände, die Standardabweichung aller RR-Intervalle (SD), die Quadratwurzel der mittleren quadrierten Differenzen aufeinander folgender RR-Intervalle (r-MSSD), die prozentuale Rate der Unterschiede zwischen angrenzenden RR-Intervallen (pNN50), die gesamte Power (TP), niedrige Frequenz (LF), hohe Frequenz (HF) und das LF/HF-Verhältnis.Ergebnisse:Die HRV-Indizes waren in beiden Kontrollgruppen identisch, bei Patienten mit ToF dagegen signifikant erniedrigt. Innerhalb der operierten Gruppen (ToF) waren die HRV-Indizes bei sieben Patienten mit nicht anhaltenden Kammertachykardien im Vergleich zu denjenigen ohne signifikant erniedrigt: SD (95 ± 15 vs. 135 ± 54 ms; p = 0,01), r-MSSD (26 ± 9 vs. 45 ± 20 ms; p = 0,03), pNN50 (4,4 ± 3,4 vs. 16,5 ± 12,5%; p = 0,001) und HF (111 ± 97 vs. 352 ± 291 ms2; p = 0,009). Eine schrittweise multivariate Regressionsanalyse zeigte pNN50, das Operationsalter, den Grad der pulmonalen Regurgitation und ein größeres Verhältnis von rechtem zu linkem Ventrikel als unabhängige prädiktive Variablen für Kammertachykardien (p < 0,0001; r2 = 0,85).Schlussfolgerung:Patienten mit ToF, insbesondere diejenigen mit Kammertachykardien, haben eine signifikante Störung des sympathikovagalen Gleichgewichtes, was durch eine Reduktion des vagalen Tonus geprägt ist.