Sencan Özme

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.

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.

Causes of syncope in children: a prospective study

We prospectively evaluated 80 patients with syncope, between January 1991 and January 1992 to determine the causes of syncope in children. There were 35 male and 45 female patients, whose mean age was 10.5 years. A single syncopal attack had occurred in 30 patients and multiple attacks in 50. A cardiovascular cause was established in 22 (27.5%) patients and a noncardiovascular cause in 36 (45%). The cause remained unknown in 22 patients (27.5%). Vasovagal syncope was the leading cause of syncope in these patients with an incidence of 32.5%. These findings suggest that every patient who has even one syncopal attack should be promptly investigated since the underlying cause could be a life-threatening one.

Mitral and aortic insufficiency in polyarticular juvenile rheumatoid arthritis.

SummaryValvar heart disease is a rare complication of juvenile rheumatoid arthritis (JRA), the aortic valve being most commonly affected. Reported cases with symptomatic mitral involvement are rare. We describe a 13-year-old boy with seronegative, polyarticular onset of JRA in whom mitral and aortic valve insufficiency was diagnosed by clinical and laboratory investigations. Two-dimensional and continuous-wave Doppler echocardiography confirmed mild pericardial effusion with moderate mitral and mild aortic insufficiency. Cardiac assessment and echocardiogrphic follow-up are recommended in all patients with JRA.

Parameters of iron deficiency in children with cyanotic congenital heart disease

A group of 67 children with cyanotic congenital heart disease (CCHD) were studied, and 35 were given iron treatment according to a regimen that gives iron to patients with a hematocrit (Hct) below 60%. The patients were categorized as iron-deficient and iron-sufficient according to their transferrin saturation and ferritin values. The pretreatment hemoglobin (Hb) and Hct values of the groups were similar. The mean Hct was nearly three times as much as the mean Hb in the iron-sufficient group and more than three times as much as the Hb in the iron-deficient group. Excessive erythrocytosis in the iron-deficient group was impressive. Mean corpuscular volume (MCV) values were below 72.7 fl in all of the iron-deficient patients. After treatment the Hb, Hct, transferrin saturation, and ferritin increased significantly in both groups, with the increments greater in the iron-deficient group. Increments in the erythrocyte (RBC) count were significant in the iron-sufficient group but insignificant in the iron-deficient one. Increments of MCV in the iron-deficient group were significant but insignificant in the iron-sufficient group. Our study demonstrated that prediction of Hb, RBC count, and MCV, measurements of which are easy and inexpensive and require little blood, can suffice for the diagnosis of iron deficiency in patients with CCHD without altering systemic perfusion.

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.

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 (Ac‐cufix 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 m V versus 9.4 ± 3.2 mV (P > 0.05), and mean impedance as 557 ± 92 Ω versus 664 ± 160 Ω (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.

Left ventricular structure and function by echocardiography in congenital muscular dystrophy

Cardiac involvement in congenital muscular dystrophy (CMD) has not previously been reported in the literature excepting Japanese ones. The purpose of this study was to investigate the probability of cardiac muscle involvement in 25 patients with CMD. Left ventricular dimensions, wall thicknesses and function were investigated by M-mode and Doppler echocardiography in patients and healthy control subjects. The M-mode echocardiographic data were similar in the two groups. However, the left ventricular mass index in the study group was significantly lower than that of the control group. Left ventricular diastolic function also differed significantly when compared with that of the control group. Mild diastolic dysfunction of the left ventricle might precede manifestations of probable cardiac muscle involvement or subclinical cardiac involvement.

Dysrhythmia as a cause of syncope in children without neurological or cardiac morphological abnormalities

Background : Arrhythmias are among the malignant causes of syncope. This study has been undertaken to determine the relative incidence and significance of dysrhythmia in the pathogenesis of syncope among patients referred to a pediatric cardiology unit.