Unusual extraction of an active fixation ventricular pacing lead with outer coil fracture in a child.

AIM: In this report we describe an asymptomatic paced child with outer coil fracture of the bipolar screw-in steroid eluting ventricular lead without insulation defect, loss of ventricular capture and unexpected increase in lead impedance in the bipolar VVIR pace configuration. METHOD AND RESULT: A previously unpublished method was performed to retract the helix and the lead. As a result, the fractured lead was successfully retrieved. CONCLUSION: We suggest that, this unusual extraction method can be tried as an alternative approach in the removal of an active fixation ventricular pacing lead with impaired mechanical function possibly due to fracture.

Sotalol in treatment of pediatric cardiac arrhythmias.

BACKGROUND: There is limited experience on sotalol use in the management of childhood arrhythmias. This study reviews the results of our experience with oral sotalol for treatment and prevention of tachyarrhythmias in children. METHODS: The records of 62 patients (27 female, 35 male, mean age: 8.5+/-5.3 years) treated with sotalol for supraventricular or ventricular arrhythmias from 1994 to 1999 at our institution were reviewed. Demographic, clinical, echocardiographic, electrocardiographic (ECG), ambulatory ECG and electrophysiologic variables were collected. RESULTS: Forty-two (63.6%) patients had re-entrant supraventricular tachycardia, eight patients (12.9%) had atrial tachycardia, one patient (1.6%) had junctional ectopic tachycardia, four patients (6.5%) had ventricular tachycardia, and seven patients (11.3%) had complex ventricular arrhythmias, as evidenced by surface or ambulatory ECG records; or revealed during the electrophysiological study. The mean sotalol dose was 3.9+/-1.2 mg/kg per day. In 15.5+/-13.9 months of sotalol use 50% (n=31) had complete relief of symptoms and/or arrhythmia and 29% (n=18) had partial relief. Sotalol was ineffective in 20% (n=13). Sotalol was more effective in re-entrant type supraventricular tachycardias (P=0.012). Sotalol was the first choice in 35.5% of patients. The sotalol therapy was initiated in inpatient settings in 40.3% (25 patients). Complications due to sotalol were seen in six patients (five patients developed bradycardia/pauses, and one patient had torsades de pointes) for which the sotalol dose was modified. In patients with sick sinus syndrome, a pacemaker was implanted and in another patient sotalol was stopped. CONCLUSION: Sotalol, being an effective and safe drug particularly in children, is a good therapeutic alternative for the preventive treatment of childhood tachyarrhythmias.

Microdeletion of 22q11 (CATCH 22) in children with conotruncal heart defect and extracardiac malformations.

CATCH 22 is a medical acronym for cardiac defects, abnormal facies, thymic hypoplasia, cleft palate, and hypocalcemia, and a variable deletion on chromosome 22q11. The deletion within the chromosome region of 22q11 may occur in patients with dysmorphologic and cardiological syndromes: DiGeorge syndrome (DGS), velocardiofacial syndrome (VCFS), and conotruncal anomaly face syndrome (CAFS). In this study, using N25 (D22S75) DiGeorge chromosome region probe. fluorescence in situ hybridization (FISH) analyses were performed on 32 patients with congenital heart diseases. Twenty-nine of 32 patients had conotruncal heart disease. A 22q11 deletion was detected in two patients (6.9%) of the 29 patients with conotruncal heart disease. One of our 22qdel (+) patients had unilateral facial nerve palsy. Although it is not a frequent finding, unilateral facial nerve palsy will be included among the symptoms of CATCH 22 syndrome. After careful clinical evaluation of patients with conotruncal cardiac anomalies, only syndromic cases should be screened for this deletion.

Comparison of mid-term clinical experience with steroid-eluting active and passive fixation ventricular electrodes in children.

Although active fixation ventricular leads seem to have advantages over passive fixation leads, this study compares the follow-up results of active and passive fixation leads in children. We evaluated the implantation and follow-up data of 41 children with active (Accufix II DEC, group 1) (n = 20) or passive (Membrane E, group 2) (n = 21) fixation, steroid-eluting ventricular leads. All but one of the patients in group 1 completed the 12-month follow-up. The mean follow-up period in group 2 was 10.4 +/- 2.9 months (range 3-12 months, median 12 months). In both groups the mean pacing threshold was measured as 0.51 +/- 0.09 V versus 0.48 +/- 0.15 V (P > 0.05) at 0.5-ms pulse width, mean R wave amplitude as 9.9 +/- 2.5 mV versus 9.4 +/- 3.2 mV (P > 0.05), and mean impedance as 557 +/- 92 omega versus 664 +/- 160 omega (P < 0.05), respectively, at implantation. After the first week of pacing, mean threshold values in group 1 were significantly lower than those of group 2 (P < 0.01 and P < 0.05, respectively). During the follow-up period, lead impedance measurements did not show a significant difference between the two groups. In one patient from group 1, the lead (by unscrewing) was removed easily because of pacemaker pocket infection. No lead dislodgement or helix deformation occurred in group 1. Nevertheless, in one patient from group 2, the lead was extracted at 4-month postimplantation because of lead displacement. We conclude that the steroid-eluting active fixation lead (Accufix II DEC) have advantages of easier implantation and lower acute and chronic stimulation thresholds compared to the passive fixation lead (Membrane E). Therefore, Accufix II DEC is superior to Membrane E, and it is a better first choice in children with an implanted single chamber ventricular pacemaker.

A cross section of autosomal recessive limb-girdle muscular dystrophies in 38 families.

Limb-girdle muscular dystrophies constitute a broad range of clinical and genetic entities. We have evaluated 38 autosomal recessive limb-girdle muscular dystrophy (LGMD2) families by linkage analysis for the known loci of LGMD2A-F and protein studies using immunofluorescence and western blotting of the sarcoglycan complex. One index case in each family was investigated thoroughly. The age of onset and the current ages were between 11/2 and 15 years and 6 and 36 years, respectively. The classification of families was as follows: calpainopathy 7, dysferlinopathy 3, alpha sarcoglycan deficiency 2, beta sarcoglycan deficiency 7, gamma sarcoglycan deficiency 5, delta sarcoglycan deficiency 1, and merosinopathy 2. There were two families showing an Emery-Dreifuss phenotype and nine showing no linkage to the LGMD2A-F loci, and they had preserved sarcoglycans. gamma sarcoglycan deficiency seems to be the most severe group as a whole, whereas dysferlinopathy is the mildest. Interfamilial variation was not uncommon. Cardiomyopathy was not present in any of the families. In sarcoglycan deficiencies, sarcoglycans other than the primary ones may also be considerably reduced; however, this may not be reflected in the phenotype. Many cases of primary gamma sarcoglycan deficiency showed normal or only mildly abnormal delta sarcoglycan staining.

Evaluation by exercise testing of children with mild and moderate valvular aortic stenosis.

BACKGROUND: The aim of the present paper was to determine the factors related to sudden death in aortic stenosis. METHODS: The factors related to sudden death were investigated in 40 asymptomatic children with mild and moderate aortic stenosis by treadmill testing. RESULTS: The QT interval of aortic stenosis cases were significantly longer than those of healthy children with increasing heart rates during exercise. CONCLUSIONS: A longer QT interval of aortic stenosis cases compared to normal children during exercise is the first sign of myocardial ischemia and leads to fatal ventricular arrhythmias and sudden death. For this reason we recommend that exercise testing should be performed frequently in aortic stenosis patients and that close follow up is necessary for patients with long QT segments that can be a marker for severe arrhythmias.

Analysis of 2017 Holter records in pediatric patients.

Holter monitoring (HM) is widely used in arrhythmic disorders of adult patients; however, studies in the pediatric age group are limited. This study aims to determine the value of HM in diagnosis and treatment of disorders related to arrhythmias in pediatric patients. We examined 2,017 Holter records of 1,500 children who applied to our institution between November 1994 and October 1998. The age ranged from 0-24 years (52% male, 48% female). The indications for HM were screening for arrhythmic symptoms (palpitation, chest pain, syncope) in 67 percent, monitoring dysrhythmic therapy in 17 percent, postoperative control in five percent, and pacemaker control in four percent. Palpitation is the leading presenting symptom, with more frequent findings of supraventricular extrasystole (SVE), supraventricular tachycardia (SVT), ventricular extrasystole (VE) and complete heart block (CHB) when compared to other symptoms. Only 5.3 percent of the patients had arrhythmic symptoms during monitoring and asymptomatic patients had more frequent arrhythmias. SVT, VE, and CHB are more frequent findings in the abnormal heart with previous cardiac operations. The diagnostic yield is low with arrhythmic symptoms in the pediatric age group; however, HM enables cumulative evaluation of heart rhythm and rhythm variability, which is important in diagnosing silent arrhythmias in high risk groups (abnormal heart, postoperative heart).

Congenital sick sinus syndrome with breath holding and severe syncope episodes during infancy. A case report.

Sick sinus syndrome is a rare cause of bradycardia in children without structural heart disease. A case of profound sinus bradycardia, sinus arrest with junctional escape, and pauses in a two-year-old infant with breath-holding and syncope episodes is presented. As a result of these clinical symptoms and electrocardiographic findings, the patient with sick sinus syndrome underwent implantation of transvenous ventricular pacemaker. He has been well and asymptomatic since the insertion of the pacemaker. In the differential diagnosis of an infant with breath-holding and syncope episodes, when these symptoms in particular cannot be explained by other common reasons, sick sinus syndrome should be kept in mind. This case also illustrates the importance of electrocardiographic studies for the diagnosis.

Clinical and genetic correlate in childhood onset Friedreich ataxia.

We analyzed the clinical and genetic aspects of 28 FRDA patients from 20 families. 19 families were consanguineous. The onset was between 4 and 13 1/2 years of age (mean 15.4 +/- 6.2). Three patients presented with cardiomyopathy, one with weakness, and the rest with ataxia. There were two patients with preserved lower-limb deep tendon reflexes. Sensory nerve action potentials were reduced in 14/14 patients. Cardiac echograms were abnormal in 17/19 cases, and this was between 6 and 16 years of age (mean 10.1 +/- 3.5). Four families were multiplex. Clinical intra-familial variability was observed. Increased GAA repeats of the X25 gene were found in 27/28 patients studied, all in a homozygous state. 88.9% of patients had a smaller allele larger than 500 repeats, and 66.7% had more than 700 repeats. The patient who did not have increased GAA repeats in both alleles had peculiar findings. Significant correlation of expansion was obtained for the early onset, and cardiomyopathy as the onset.

Comparison of normal sinus rhythm and pacing rate in children with minute ventilation single chamber rate adaptive permanent pacemakers.

Rate adaptive pacemakers are used to achieve a better cardiac performance during exercise by increasing the heart rate and cardiac output. The ideal rate adaptive sensor should be able to mimic sinus node modulation under various degrees of exercise and other metabolic needs. Minute ventilation sensing has proven to be one of the most accurate sensor systems. In this study, alterations in sinus rhythm and pacing rates during daily life conditions in 11 children (median age 11 years, range 6-14 years) with minute ventilation single chamber pacemakers were investigated. Correlation of sinus rhythm with pacing rates was assessed. ECG records were obtained from 24-hour Holter monitoring. Average rates of five consecutive P waves and pace waves were determined every half hour. The average of the two values was then used to determine hourly rates. Correlation coefficients between the sinus rhythm and pacing rates were calculated. In nine patients, pacing rates correlated well to sinus rhythm (range 0.6793-0.9558, P < 0.001 and P < 0.05), whereas in two cases correlation was not sufficient (P > 0.05). Most of the patients, in whom rate response factor (RRF) measurements during peak exercise by treadmill with chronotropic assessment exercise protocol were performed and pacemakers were programmed to these parameters, had more appropriate ventricular rates compared to spontaneous sinus rates. In these patients mean RRF value was 15.3 +/- 2.7 (range 12-20, median 15). This study shows that during daily activities minute ventilation rate adaptive pacemakers can achieve pacing rates well correlated to sinus rhythm that reflects the physiological heart rate in children.

Effectiveness and safety of intravenous amiodarone in drug-resistant tachyarrhythmias of children.

BACKGROUND: Experience with pediatric use of intravenous amiodarone is limited. In this study, our experiences with intravenous amiodarone in children with acute life-threatening or chronic tachyarrhythmias are reviewed. METHODS AND RESULTS: Twelve patients, with a mean age of 3.4 +/- 3.1 years, range 9 months-10 years (two with incessant ventricular tachycardia, one with ectopic atrial tachycardia, two with atrioventricular re-entrant tachycardia (three episodes), four with postoperative or congenital junctional ectopic tachycardia, two with bradycardia-tachycardia syndrome, one with atrial tachycardia) were treated with intravenous amiodarone during 13 tachycardia episodes. Left ventricular systolic functions were depressed in six patients. In 11 patients, a median of two drugs (range one-four), including adenosine infusion and in five cases direct current cardioversion were tried without success prior to intravenous amiodarone. The loading dose of amiodarone was 5 mg/kg in all episodes, infused over 1 h. Maintenance infusion was required in 12 episodes. In 10 episodes (77%), amiodarone was considered effective, in one (7.6%) partially effective (junctional ectopic tachycardia) and in two (15.4%) ineffective (sick sinus syndrome, atrial tachycardia). Therapeutic effect was obtained in a median period of 30 h (range 1-103 h). The mean effective maintenance dose was 10 +/- 4.7 micrograms/kg per min (range 5-15 micrograms/kg per min). In one patient, mild hypotension, and in three patients cellulitis occurred, but none of them necessitated termination of treatment. CONCLUSIONS: Intravenous amiodarone is found to be an effective and safe antiarrhythmic agent for children with acute life-threatening and chronic tachyarrhythmias and depressed left ventricular systolic functions.

Role of adenosine in the diagnosis and treatment of tachyarrhythmias in pediatric patients.

Tachyarrhythmias are common rhythm disturbances in infants and children. Despite the availability of diagnostic criteria arrhythmias are sometimes commonly misdiagnosed. Recent reports suggest that an endogenous purine nucleoside, adenosine, has a diagnostic effect in narrow QRS complex tachycardias, in addition to terminating supraventricular tachycardia involving the atrioventricular node. This report reviews the authors' experience with the use of adenosine for diagnosis of narrow and wide complex tachyarrhythmias in children. Adenosine was administered to 43 patients with several types of tachyarrhythmias (mean age, 8.3 +/- 5.24 years). Nineteen patients had structural or acquired heart disease. Of the 43 patients there were 28 (65%) several different types of narrow QRS complex tachycardia and 14 (33%) ventricular arrhythmias. One patient (2%) had long QT. Adenosine terminated supraventricular tachycardia, in 11 of 12 patients (92%), ventricular tachycardia in five of eight patients (63%), and transiently terminated premature ventricular contractions in two of six patients (33%). The diagnostic ability of adenosine was perfect in eight supraventricular tachycardia. In these eight cases the tachycardia mechanism was unclear before the administration of adenosine, which demonstrated three cases of sinus tachycardia, three of atrial flutter, one of atrial fibrillation and one of atrial fibrilloflutter. Confirmation of the primary diagnosis by adenosine was perfect in five tachyarrhythmias including three cases of atrial flutter, one of atrial fibrillation and one of ectopic atrial tachycardia. The average effective dose of adenosine was 212 micrograms/kg (range, 100-400 micrograms/kg). There were no serious side-effects except transient dyspnea, chest pain and flushing. These findings demonstrate adenosine to be helpful and safe in the diagnosis of tachyarrhythmias.

The role of serotonin re-uptake inhibitors in preventing recurrent unexplained childhood syncope -- a preliminary report.

UNLABELLED: To assess the efficacy of a serotonin re-uptake inhibitor, sertraline hydrochloride, in preventing recurrent neurocardiogenic syncope, we studied 15 patients (10 female; mean age 12.9 +/- 2 years) with positive head-upright tilt test and resistant to standard pharmacotherapy, atenolol or disopyramide. The patients were given 50 mg oral sertraline hydrochloride daily for 6 weeks. Intolerance to the drug was seen in 3 patients and 2 had syncopal episodes during the therapy. A head-upright tilt table test was then repeated in 10 patients. Six were tilt negative and asymptomatic over a mean follow up period of 7 +/- 3 months while four remained tilt positive: two experienced marked hypotension and bradycardia, characterized as mixed type syncope, and two had cardiac asystole, lasting > 10 s, during tilting, thereby exhibiting a cardio-inhibitory response. CONCLUSION: Sertraline hydrochloride may be useful in preventing recurrent neurocardiogenic syncope resistant to standard pharmacotherapy but careful clinical studies are essential before such a treatment strategy can be recommended since serious asystole could develop.

Calpain-3 deficiency causes a mild muscular dystrophy in childhood.

Among our 20 families with LGMD2, 10 were documented to have muscle-specific calcium-activated neutral protease 3 (calpain-3) deficiency. Consanguinity was present in all. The current ages of the index cases were between 12 and 23 years, and there were additional nine members affected. Clinically, the patients showed mild courses; none of the cases below age 30 lost autonomy so far. The dystrophy is mainly proximal and atrophic with calf enlargement and scapular wasting in some. In three cases walking was delayed. Creatine kinase levels were at least 10 times elevated. All obligate carriers had normal creatine kinase levels. Five families shared the same 551 delA frameshift mutation. In four of these families there was the same core haplotype, whereas one was distinct suggesting an independent origin. Calpain-3 deficiency in general is a mild muscular dystrophy during childhood.

Long-term clinical experience with a steroid-eluting active fixation ventricular electrode in children.

In this study, the first study performed in pediatric patients, we assessed the safety and efficacy of a steroid-eluting active fixation ventricular electrode in 18 children. Our study shows that steroid-eluting active fixation leads are safe and effective in children, and suggests that these leads with their easy implantation and low chronic threshold values may be considered as the first choice in this age group.

Comparison of sensitivity and specificity of tilt protocols with and without isoproterenol in children with unexplained syncope.

Head-up tilt testing with or without isoproterenol is extensively used in the evaluation of patients with unexplained syncope. However, sensitivity and specificity of tilt protocols with and without isoproterenol have not been clarified in children, due to lack of age matched control subjects. This study was designed to assess and to compare the sensitivity and specificity of tilting alone and tilting in conjunction with isoproterenol. Thirty children with unexplained syncope (group I) and 15 age-matched control subjects (control group I) underwent successive 60 degrees head-up tilts for 10 minutes during infusions of 0.02, 0.04, and 0.06 microgram/kg/min of isoproterenol, after a baseline tilt to 60 degrees for 25 minutes. Also, 35 children (group II) with unexplained syncope and 15 healthy control subjects (control group II) were evaluated by head-up tilt to 60 degrees for 45 minutes without an infusion of isoproterenol. In response to tilt protocol with graded isoproterenol, 23 (76.6%) of the patients in group I and 2 of the 15 (13.3%) control subjects developed syncope. Accordingly, the sensitivity of tilt testing with isoproterenol was 76.6%, and its specificity was 86.7%. Tilt testing without isoproterenol was positive in 17 (48.5%) of the patients in group II but in only 1 of the 15 (6.6%) control subjects. Thus, sensitivity and specificity of tilt testing without isoproterenol were 48.5% and 93.4%, respectively. The mean heart rate and systolic blood pressure decreased significantly (P < 0.001) in all tilt positive patients during syncope. In conclusion, the head-up tilt test is a valuable diagnostic test in the evaluation of children with unexplained syncope, and isoproterenol is likely to increase the sensitivity of the test without decreasing its specificity.

Dual sensor pacemakers in children: what is the choice of sensor blending?

UNLABELLED: Dual sensor pacemakers were developed to obtain more appropriate responses to activity. We evaluated ten children with dual sensor pacemakers in different sensor blending circumstances using exercise testing to assess which ratio was optimal. Ten patients with several bradydysrhythmias (ages 6-16 years; mean 10.1 years) were included in the study. Eight patients had VVIR pacemakers (Vitatron Topaz), models and two patients had VDD pacemakers implanted via the transvenous route. All patients were in a paced rhythm (98.5% pacing). Accurate T wave sensing ranged from 81%-100%; mean 92%, median 95%. Voluntary exercise testing with a CAEP protocol was performed using a treadmill with the pacemaker in VVIR mode. Medium activity threshold with three sensor blending ratios (QT = ACT, QT > ACT, and QT < ACT) were done in all patients. The mean duration of exercise was not statistically different among the three sensor blending ratios. After 90 seconds of exercise, the mean pacing rate had increased by 12%, 3%, and 5%, respectively, in the three groups. At maximal exercise, the increases were 45%, 42%, and 54%. Mean HRs during exercise in each of the three ratios were not significantly different, although we found a statistically significant increase in HR during the first two stages of rest period in the QT = ACT sensor blending ratio compared to the QT > ACT ratio. No difference was observed after the second stage. IN CONCLUSION: (1) there is no difference between the QT = ACT, QT < ACT, and QT > ACT sensor blending ratios; and (2) each child has to be evaluated by exercise testing to program a correct sensor blending ratio.

Short- and intermediate-term efficacy of amiodarone in infants and children with cardiac arrhythmia.

The antiarrhythmic effect of amiodarone was examined in this retrospective study in a group of 20 patients with a mean age of 8.5 +/- 6.7 years (range 42 days to 20 years, median 9 years). Five patients with atrial flutter, one patient with atrial fibrillation, two patients with an intermediate rhythm between atrial flutter and atrial fibrillation, four patients with chaotic atrial tachycardia, three patients with atrioventricular reentry tachycardia, two patients with junctional ectopic tachycardia, and three patients with ventricular arrhythmias were treated with amiodarone. The mean duration of therapy was 9.1 +/- 12.3 months (range 1 month to 4 years). Before amiodarone treatment, 18 patients had been unresponsive to various antiarrhythmic drugs (range 1-8, median 2). Two patients received amiodarone as an initial therapy. It was administered orally at a dose of 10 mg/kg once per day for 10 days and then decreased to 5 mg/kg once per day. Amiodarone was effective in 16 patients (80%). Side effects occurred in three patients, including thyroid dysfunction, elevation of liver enzymes, and keratopathy. All side effects disappeared upon cessation of the therapy. We recommend amiodarone for the treatment of childhood arrhythmias, especially for the refractory types.

The angiocardiographic analysis of 73 patients with double-outlet right ventricle.

The purpose of this study was to determine the cardiac anatomy of patients with double-outlet right ventricle by angiocardiography. A total of 73 patients between the ages of one day and 11 years were examined. The aorta was on the right side of the pulmonary artery in 23 cases (32%), right anterior in 20 (27%) and right posterior in 17 cases (23%). Pulmonary stenosis was found in 53 patients (73%) and subaortic stenosis in six cases. Ventricular septal defect (VSD) was subaortic in 39 cases (52%), remote type in 17 (23%), doubly committed in 10 (13%), and subpulmonic in 9 (12%). Double VSD was noted in two patients. Pulmonary hypertension was more frequent in subpulmonic ventricular septal defect (78%). The most common associated anomalies were atrial septal defect (34%), anomalous coronary arteries (12%) and endocardial cushion defect (10%). Aortic root angiography was not satisfactory in half of the cases with coronary arterial anomaly. In conclusion, double-outlet right ventricle is a complex anomaly, all of whose cardiac features can be successfully demonstrated in detail by echocardiography and angiocardiography. However, in order to determine the anatomy of the coronary arteries, selective coronary angiography may be necessary in some patients.

Transtelephonic ECG versus electrophysiologic study in children with recurrent palpitation attacks.

Palpitation may be a terrifying event for children and pose diagnostic problems for pediatric cardiologists. Routine methods often fail to document episodic arrhythmia because the episodes may be brief or infrequent or both. The purpose of this study was to evaluate and compare values of non-invasive and invasive techniques. Twenty-three children (mean age 11.7 +/- 2 years, range 7-16 years) with recurrent palpitation attacks (> 2 times), who had normal physical examinations, ECG, echocardiography, 24 hour ambulatory ECG monitoring and treadmill exercise tests, were included in the study. Redline Model CG 4000 TTE recorders were given to patients for 10 or 20 days. We performed an intracardiac electrophysiologic study (EPS) on 14 patients. The mean number of palpitation attacks was 11.3 +/- 7.4 (median: 5), lasting 9.6 +/- 7 (median 3) minutes. The number of transmitting records was 2 +/- 1.4 (1-20). Of the 23 patients, only 15 (65%) transmitted during the palpitation attacks. Twenty-four-hour ambulatory ECG monitoring findings were normal in all patients. One patient had a wide QRS tachycardia attack in the TTE records. We stimulated ventricular tachycardia in the same patient in the EPS. Among the other patients who transmitted TTE records during palpitation attacks, we diagnosed two cases of concealed accessory pathway and eight cases of dual AV nodal pathway in the EPS. In conclusion, TTE is a sensitive and accurate method for diagnosis and follow-up of patients with cardiac arrhythmia. It can be used before invasive studies in children with recurrent palpitation attacks.