The ability to record accessory atrioventricular (AV) pathway activation consistently may be uniquely beneficial in improving pathway localization, identifying anatomic relations, and providing insight into unusual conduction properties. For the purpose of recording left AV accessory pathway activation, an electrode catheter was specially designed for use in the coronary sinus. The orthogonal catheter has three sets of four electrodes spaced evenly around the circumference. Electrograms were recorded at low gain (<1 cm/mV) between adjacent electrodes on the same set (interelectrode distance, 1.5 mm, center to center). This provides a recording dipole perpendicular to the atrioventricular groove to enhance recording of accessory pathway activation while miinimizing overlapping atrial or ventricular potentials. The orthogonal electrode catheter was used in the electrophysiological study of 48 consecutive patients with 59 left AV accessory pathways. The catheter could be advanced along the coronary sinus beyond the site of earliest retrograde atrial activation in 49 of the 59 accessory pathways. Activation potentials were recorded from 45 of the 49 (92%) accessory pathways accessible to the catheter (5 of 5 anterior, 8 of 8 anterolateral, 15 of 16 lateral, 5 of 5 posterolateral, 5 of 5 posterior, and 7 of 10 posteroseptal). Accessory pathway potentials were validated by dissociating them from both atrial and ventricular activation by programmed-stimulation techniques. During surgery, accessory pathway potentials were identfied from orthogonal catheter electrodes in the coronary sinus in 14 of 16 accessory pathways (12 patients). Epicardial mapping confirmed the location of the accessory pathway, and direct pressure over the orthogonal catheter electrode that recorded the accessory pathway potential resulted in transient conduction block in nine of the 14 accessory pathways. Orthogonal electrode maps of the coronary sinus identified an oblique course in 39 of 45 recorded accessory pathways. Thirty-two of 38 left free-wall accessory pathways were oriented with atrial insertion 4-30 mm (median, 14 mm) proximal (posterior) to the ventricular insertion. In the remaining six free-wail accessory pathways, the lateral excursion could not be determined because either only the atrial end of the accessory pathway was recorded or activation of multiple pathway fibers prevented tracking of individual strands. The seven recorded posteroseptal pathways exhibited accessory pathway potentials throughout an 8-18-mm (median, 10 mm) length of the proximal coronary sinus, but fiber orientation was difficult to determine. We conclude that left AV accessory pathway activation can be recorded consistently from orthogonal catheter electrodes in the coronary sinus. Direct accessory pathway recordings revealed an oblique fiber orientation and may provide more precise loalization for surgical or catheter ablation. (Circulation 1988;78:598-610) E a lectrophysiological studies in patients with of accessory atrioventricular (AV) pathways b...

Premature newborns and infants are usually required to successfully transition from gavage to nipple feeding using breast or bottle before discharge from the hospital. This transition is frequently the last discharge skill attained. Delayed acquisition of this skill may substantially prolong hospital length of stay. The authors describe a case of hospitalized premature twins who had considerable delays in attaining nipple-feeding skills. Because of their inability to take all feedings by nipple, preparation for surgical placement of gastrostomy tubes was initiated. Before the surgeries were scheduled, the inpatient osteopathic manipulative medicine service was consulted, and the twins received a series of evaluations and osteopathic manipulative treatment (OMT) sessions. During the OMT course, the twins' nipple feeding skills progressed to full oral feeding, which allowed them to be discharged to home without placement of gastrostomy tubes. The authors also review the literature and discuss the development of nipple feeding in premature newborns and infants and the use of OMT in the management of nipple feeding dysfunction.

The delivery of 37 shocks by an ICD within 20 minutes, in response to T wave oversensing during atrial flutter, resulted in several manifestations of undesirable device behavior. The generator reverted to backup mode, and disabled automatic capacitor reformation, therapy delivery, and automatic gain control. Postexplant analysis of the device revealed damage to the high voltage output section of the circuitry consistent with excessive electrical stress. In rare circumstances, multiple internal discharges can result in serious clinical anomalies in ICD behavior, and possibly in an increase in susceptibility to circuitry damage.

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The efficacy and safety of a new dosage regimen of intravenous disopyramide in ventricular arrhythmias were evaluated in 10 patients. Each had at least four premature ventricular contractions (PVCs)/min during a 30-min period before dosing. By the classification of Lown et al., grade III arrhythmia was present in four patients, grade IVA in three patients, and grade IVB in three patients. Disopyramide was injected intravenously as a bolus of 0.5 mg/kg over 5 min. Each patient received two to three additional boluses of same strength with 5-min intervals between each dosing during the first hour. Continuous intravenous infusion was started with the first bolus and continued at a rate of 1 mg/kg/hr for 3 hr and at 0.4 mg/kg/hr for 15 hr. All patients had continuous Holter monitoring throughout the 18-hr treatment period and for 30 to 60 min before treatment. In eight patients the grade of arrhythmia after drug decreased and the frequency of PVCs fell by 70% to 100% (greater than 85% in six patients and less than 85% in two patients), and the response persisted during the continuous infusion. In two patients PVC frequency increased. For the group as a whole, PVC frequency decreased on the average by 68.4%. Therapeutic serum levels (greater than 2 micrograms/ml) were reached after the first or second bolus and were maintained during the continuous infusion period. There were no side effects necessitating termination of disopyramide infusion. The dosage regimen of intravenous disopyramide evaluated was effective in 60% of patients with ventricular arrhythmia, induced no severe toxic effects, and rapidly achieved therapeutic serum levels that were maintained during continuous infusion.