Mustafa Koray Lenk

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° head‐up tilts for 10 minutes during infusions of 0.02, 0.04, and 0.06 μg/kg/min of isoproterenol, after a baseline tilt to 60° 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° 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 25 (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.

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

AbstractTo 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.

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 cnronotropic 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.

Transcatheter closure of patent ductus arteriosus using controlled-release coils

Controlled‐release coils have become available recently for the closure of patent ductus arteriosus (PDA). Transcatheter closure of patent arterial ducts was attempted in 13 patients, ranging in age from 5 months to 15 years, mean 4.1 years. Implantation of controlled‐release PDA coils was attempted via the femoral artery through 5 Fr catheters in all cases except one, in whom both the femoral arterial and venous routes were used. The procedure was successful in 10 of the 13 patients. In these, the pulmonary artery systolic pressure ranged between 25 and 42 mmHg and the duct diameter varied from 1.5 to 6 mm at its narrowest point. Six of the patients received a single coil. Two coils were inserted in three patients and three coils in one patient. In three patients the ducts were too large for safe release of the coils, despite attempted implantation of up to three coils simultaneously. These coils were easily withdrawn into the catheter Immediately at the end of the procedure, the duct was completely occluded in nine of the 10 patients, and in one patient there was a small residual flow. The procedure time varied between 35 min and 2.5 h, mean 81 min and the fluoroscopy time varied from 5 to 78 min, mean 25 min. None of the patients experienced hemorrhage, diminished lower extremity pulse, hemolysis or infection. In one patient, a 5 mm coil embolized into the right pulmonary artery soon after release. It was retrieved with a snare, then 8 mm and a 5 mm coil were implanted satisfactorily in the arterial duct. At follow‐up by color Doppler echocardiography, the duct was completely occluded in all patients.

Auditory brainstem responses in children with congenital heart disease.

Abstract Background: Cyanotic congenital heart diseases usually lead to growth and developmental delay in children due to chronic hypoxemia and undernourishment that may affect the central nervous system. The auditory brainstem responses are determined to assess the maturation and function of the brainstem. Therefore, we used the auditory brainstem responses to investigate the effect of cyanotic congenital heart diseases on brainstem maturation.

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

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 WIR 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 WIR 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. (PACE 1997; 20[Pt. I]:1301‐1304)

Abnormal connection of the inferior vena cava to the left atrium with double outlet right ventricle and heterotaxia: A case report

A 4-year-old boy with abnormal connection of the inferior vena cava to the left atrium and double outlet right ventricle and right atrial isomerism is presented. The anomalies were detected by echocardiography and angiography, and later verified through surgical intervention.

Kommerell diverticulum is a rare phenomenon: Aberrant left subclavian artery in association with right aortic arch and ventricular septal defect. -

Kommerell´s diverticulum can occur in a number of anomalies of the aortic arch system that can, but do not always, cause symptoms of tracheal or esophageal compression. The diverticulum is most frequently present in cases of right aortic arch with an aberrant left subclavian artery. In this anomaly, the left subclavian artery arises from the right-sided aortic arch as the 4th branch and extends behind the esophagus to the left arm. The descending aorta can be right sided or left sided. We report a 5-year-old girl with Kommerel diverticulum, minor left upper extremity anomalies and restrictive perimembranous ventricular septal defect.