Carl H. Gumbiner

Late potentials and inducible ventricular tachycardia in surgically repaired congenital heart disease.

We compared signal-averaged electrocardiography with invasive electrophysiological study in patients after surgical repair of congenital heart disease to determine if potentially useful correlations exist between the two methods for assessment of risk for ventricular tachycardia. Thirty-one patients (age, 1-49 years; mean, 10.6 years) with congenital heart disease repaired with right ventriculotomy or postrepair right bundle branch block (77% postoperative tetralogy of Fallot) who had electrophysiological study were studied with signal-averaged electrocardiography. Patients were classified by electrophysiological study results as having no inducible ventricular tachycardia, nonsustained ventricular tachycardia, or sustained ventricular tachycardia. Signal-averaged electrocardiograms were examined for the duration of low-amplitude (less than or equal to 40 microV) QRS signal, duration of total QRS, and root-mean-square voltage of the terminal 40 msec of the QRS. Low-amplitude terminal root-mean-square voltage of 100 microV or less had 91% sensitivity and 70% specificity for ventricular tachycardia inducible by electrophysiological study. Similar sensitivity but less specificity were seen using the criterion of 20 msec or more total low-amplitude QRS signal (initial plus terminal) or using total QRS duration of 128 msec or more. There was a weaker association between terminal low-amplitude QRS signal of 15 msec or more and inducible ventricular tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Survival after a severe iron poisoning treated with intermittent infusions of deferoxamine

Iron poisoning is the most common cause of overdose mortality in children under six years of age and there are no reports of survival with iron levels > 2687 mumol/L (> 15,000 micrograms/dL). A 22-month-old male was brought to the emergency department by his parents after ingesting an estimated 50 ferrous sulfate tablets (60 mg elemental iron/tablet) several hours earlier. Despite spontaneous emesis and gastric lavage his condition deteriorated and he was found to have a serum iron of 2992 mumol/L (16,706 micrograms/dL). During the first four days in the intensive care unit, he developed coma, metabolic acidosis, hypovolemic and cardiogenic shock, liver failure, coagulopathy and adult respiratory distress syndrome. He was treated with a unique deferoxamine dosage schedule (25 mg/kg/h for 12 h/d x 3 d), mechanical ventilation, Swan-Ganz catheter monitoring, dopamine/nitroprusside therapy, blood product, bicarbonate, electrolyte and volume replacement. After a prolonged hospital course complicated primarily by gastric outlet obstruction he was dismissed on full oral feedings, gaining weight, and neurologically intact. Swan-Ganz catheter monitoring guided the management of this patients shock, iron-induced cardiac failure, and deferoxamine mesylate induced adult respiratory distress syndrome. Further experience and research is required to determine the most appropriate deferoxamine mesylate dosing schedule and our experience expands the range for possible survival after massive iron overdose.

Signal‐Averaged Electrocardiography of the Terminal QRS in Healthy Young Adults

DANFORD, D.A., et al.: Signal‐Averaged Electrocardiography of the Terminal QRS in Healthy Young Adults Interpretation of signal‐averaged electrocardiograms (SAECG) in the young could he of value in detecting those at risk for episodic ventricular tachycardia, but suffers from a lack of data in normal young people. The purpose of this study is to determine normal values for QRS duration and the duration and amplitude of terminal potentials on the SAECG in young adults. Thirty‐two normal medical students were examined. With high pass fütering at 25 Hz, normal total QRS duration (QRS) varied as a function of sex and hody size whereas low amplitude signal duration (LAS) did not. Ninety‐five percent confidence limits are: QRS (male) 85–117 msec. QRS (female) 76–102 msec, and LAS 6–35 msec. Root mean square voltage of the terminal QRS showed a broad scatter, however none was < 20 microvolts. High pass filtering at 40 Hz did not change the QRS duration, but resulted in significantly longer LAS duration and diminished RMS voltage. Because of the longer QRS and shorter LAS previously reported in the presence of right bundle branch hlock, the normal values reported here should not be applied in the presence of intraventricular conduction delay following surgical repair of congenital heart disease. They will, however, provide a basis for interpretation of SAECG in young adults with normal QRS duration.

Comparison of two myoepicardial pacemaker leads: Follow-up in 80 children, adolescents and young adults

Although severai types of commercially available epicardial leads exist, few postimplantation data have been reported. To compare “screw‐in” (6917–35) leads with “stab‐on” leads (4951–35) from the same manufacturer, we reviewed the records of 80 young patients (age 8 days to 29 years) who underwent ventricular epicardial pacemaker implantation from 1973 to 1986. Follow‐up for the 57 patients with the 6917–35 model ranged from 3 months to 17 years (median 6.5 years) and for the 23 patients with the 4951–35 model 9 days to 4.25 years (median 2.0 years). Actuarial life table analysis revealed significantly (P < 0.001) fewer 4951–35 leads were functioning at each of 1–5 years after implant, compared to the 6917–35 leads. Analysis of available threshold pulse width data revealed no difference (P = 0.08) acutely (6 weeks after implant), but a significantly (P = 0.05) higher mean threshold for the 4951–35 leads was found chronically. No significant correlation was found for lead failure with age, underlying heart disease, lead site (i.e., left or right ventricle), or surgical approach. Using the sutureless, stab‐on technique, the 4951–35 lead is associated with higher thresholds and lower survival rate when compared to the 6917–35 lead.

Ventricular Fibrillation During Transesophageal Atrial Pacing in an Infant with Wolff-Parkinson- White Syndrome

SummaryA complication of transesophageal atrial pacing in an infant with Wolff-Parkinson-White syndrome (WPW) is reported. A newborn infant born with fetal hydrops had recurrent supraventricular tachycardia (SVT) that required repeated successful conversion by transesophageal atrial pacing. Because of secondary left ventricular dysfunction, digoxin was administered. During repeat transesophageal atrial pacing for recurrent SVT, ventricular fibrillation occurred. Although it is unclear which of several possible contributing factors was responsible for the ventricular fibrillation, recommendations are appropriate to minimize the risk in infants with WPW.

Omphalocele associated with coronary sinus atrial septal defect: Report of two cases

SummaryTwo children with omphalocele were found to have coronary sinus atrial septal defect as part of their congenital heart disease complex. This unusual atrial communication may elude preoperative detection unless specifically sought. Its occurrence in conjunction with omphalocele may represent more than a chance association.