NEVUS SEBACEUS: CLINICAL OUTCOME AND CONSIDERATIONS FOR PROPHYLACTIC EXCISION

Background and Objective. Nevus sebaceus is a hamartoma of the skin with the potential to develop benign and malignant neoplasms. Prophylactic surgical excision has been advocated, usually before puberty, to prevent their occurrence; however, it is the clinical impression of the authors that the development of cutaneous neoplasms is infrequent and, if they develop, they are usually benign and nonaggressive. Our objective was to investigate the clinical outcome and histopathologic findings of every single nevus sebaceus that had been excised in our institution in a five-year period. Methods. Two hundred and twenty-five consecutive cases, coded as nevus sebaceus corresponding to 175 patients were submitted to our institution between September 1987 and May 1992, and were identified among a total of 64,827 specimens. All cases were reviewed histopathologically and clinical information was obtained from the records. Specimens from 10 patients were excluded. Results. A total of nine benign neoplasms (5.4%) were identified in the 165 patients. Three patients were in their second decade of life, two in their third, two in the fifth and two in the sixth. There were five trichoblastomas, three specimens of syringocystadenoma papilliferum, and one aprocrine cystadenoma. No malignant neoplasms were found. Six of the tumors were removed either for prophylactic or cosmetic reasons and in only three cases were the neoplasms suspected clinically and excised. Conclusions. If this same tendency prevails in other prospective studies, we strongly believe that prophylactic excision of all nevus sebaceus is not warranted. Excision should be recommended only when benign or malignant neoplasms are clinically suspected or for cosmetic considerations.     

The potential for μ‐opioid receptor agonists to be anti‐emetic in humans: a review of clinical data

In animal models of vomiting, μ‐opioid (MOP, OP₃) receptors mediate both emesis and anti‐emesis. μ‐receptors within the blood–brain barrier, mediating anti‐emesis, are more rapidly accessible to lipid‐soluble μ‐opioid receptor agonists such as fentanyl than to morphine, and fentanyl has broad‐spectrum anti‐emetic effects in a number of species. Whether a similar situation exists in humans is not known. A search was performed for clinical studies comparing the emetic side effects of opioids administered peri‐operatively in an attempt to identify differences between morphine and more lipid‐soluble μ‐receptor‐selective agonists such as fentanyl. Overall, the evidence appears to suggest that fentanyl and other phenylpiperidines are associated with less nausea and vomiting than morphine, but not all studies support this, and fentanyl‐like drugs are associated with nausea and vomiting per se. Good evidence, however, exists to show that fentanyl and alfentanil do not cause more nausea and vomiting than the ultra fast‐acting remifentanil. Because remifentanil is cleared rapidly post‐operatively, such trials suggest that the emetic side effects of fentanyl and alfentanil are minimal. The clinical evidence, although limited, is at least consistent with the possibility that central μ‐opioid receptors may mediate anti‐emesis in humans. It is possible that the role of μ‐opioid agonists in anti‐emesis may become clearer in the future as a result of the use of peripheral μ‐opioid receptor antagonists.     

Active Fixation Atrial Leads: Randomized Comparison of Two Lead Designs

Active fixation leads have reduced the incidence of lead dislodgement in patients with permanent pacemakers. However, theoretic concern that the tissue trauma associated with a myocardial screw-helix may increase the chronic pacing threshold of active compared to passive fixation leads has remained. Whether active fixation leads with a stimulating electrode that is independent of the fixation mechanism are associated with a lower chronic pacing threshold than leads utilizing a screw-helix for both fixation and stimulation is unknown. The present prospective, randomized study compared the acute and chronic atrial pacing and sensing characteristics of two unipolar active fixation leads, one utilizing a screw-helix for both fixation and electrical stimulation, the other with an active porous tip electrode and an electrically inactive helix. Patients were randomized to receive either a Medtronic 6957J lead with an electrically active myocardial screw-helix or a Cordis 329-101P lead with an inactive helix and a porous tip electrode. The baseline characteristics of the groups were comparable. At implantation, the 329-101P lead had a lower mean voltage threshold than the 6957J lead (0.61 +/- 0.16 V vs 1.05 +/- 0.34 V, P = 0.0004). There were no significant differences in atrial electrogram amplitude, slew rate, or lead impedance between the groups. At 6 weeks follow-up, there were no differences in the mean threshold voltage (1.85 +/- 0.36 vs 1.93 +/- 0.69 V), impedance (528 +/- 81 vs 530 +/- 118 ohms), or atrial electrogram amplitude (2.63 +/- 0.50 vs 2.42 +/- 0.95 mV) between the two leads. At long-term follow-up (mean 16.2 +/- 2.8 months, range 13.1-20.0 months) there were no significant differences in voltage threshold (1.65 +/- 0.61 vs 1.97 +/- 0.64 V), impedance (565.5 +/- 81.6 vs 617.7 +/- 146.7 ohms), or atrial electrogram amplitude (2.79 +/- 0.75 vs 3.10 +/- 1.53 mV). Thus, these results suggest that active fixation leads in the atrium with an electrode that is independent of the fixation mechanism do not provide chronic stimulation thresholds or electrogram amplitudes that are superior to those obtained with leads utilizing a myocardial screw-helix as both the active electrode and the fixation device.     

Prospective Randomized Comparison of the Safety and Effectiveness of Placement of Endocardial Pacemaker and Defibrillator Leads Using the Extrathoracic Subclavian Vein Guided by Contrast Venography Versus the Cephalic Approach

CALKINS, H., et al. : Prospective Randomized Comparison of the Safety and Effectiveness of Placement of Endocardial Pacemaker and Defibrillator Leads Using the Extrathoracic Subclavian Vein Guided by Contrast Venography Versus the Cephalic Approach. The purpose of this prospective randomized study was to compare the safety and efficacy of the cephalic approach versus a contrast-guided extrathoracic approach for placement of endocardial leads. Despite an increased incidence of lead fracture, the intrathoracic subclavian approach remains the dominant approach for placement of pacemaker and implantable defibrillator leads. Although this complication can be prevented by lead placement in the cephalic vein or by lead placement in the extrathoracic subclavian or axillary vein, these approaches have not gained acceptance. A total of 200 patients were randomized to undergo placement of pacemaker or implantable defibrillator leads via the contrast-guided extrathoracic subclavian vein approach or the cephalic approach. Lead placement was accomplished in 99 of the 100 patients randomized to the extrathoracic subclavian vein approach as compared to 64 of 100 patients using the cephalic approach. In addition to a higher initial success rate, the extrathoracic subclavian vein medial approach was determined to be preferable as evidenced by a shorter procedure time and less blood loss. There was no difference in the incidence of complications. In conclusion, these results demonstrate that lead placement in the extrathoracic subclavian vein guided by contrast venography is effective and safe. It was also associated with no increased risk of complications as compared with the cephalic approach. These findings suggest that the contrast-guided approach to the extrathoracic portion of the subclavian vein should be considered as an alternative to the cephalic approach.     

Nonreentrant Supraventricular Tachycardia Misdiagnosed as Inappropriate Sinus Tachycardia

We report a case of a woman with incessant palpitations initially misdiagnosed as inappropriate sinus tachycardia that proved refractory to β‐blockers. At the time of electrophysiologic testing, a sustained narrow‐complex tachycardia with a 1:2 atrioventricular relationship was repeatedly initiated by a posterior fascicle depolarization induced by means of a timed ventricular extrastimulus. The tachycardia was repeatedly terminated with a timed atrial extrastimulus, which excluded junctional bigeminy and confirmed the diagnosis of nonreentrant supraventricular tachycardia. Catheter ablation of the slow pathway eliminated dual‐pathway conduction and tachycardia. (PACE 2011; 34:e70–e73)     

The effect of gastrostomy tube feeding on body protein and bone mineralization in children with quadriplegic cerebral palsy

Aim The aim of this study was to investigate the effect of gastrostomy tube feeding on body protein and bone mineralization in malnourished children with cerebral palsy (CP). Method Children aged between 4 and 18 years with spastic quadriplegic CP (Gross Motor Function Classification System level V) were recruited from the Children’s Hospital at Westmead to participate in this prospective cohort study. The children had measurements of anthropometry (weight, height, and skinfold), bone mineral content (BMC) by dual‐energy X‐ray absorptiometry, and total body protein (TBP) by neutron activation analysis before and after gastrostomy tube feeding. Comparison data were collected prospectively from age‐matched healthy children and extracted from databases for this study. Results A total of 21 children (nine females, 12 males) participated in the study (median age 8y 5mo; interquartile range [IQR] 6y 9mo–11y 10mo). The median length of time of gastrostomy feeding was 19.4 months (IQR 7.7–29.9mo). Significant (p<0.05) improvements were found in the median values for weight (15.4–23.3kg), weight standard deviation scores (SDS; ?4.8 to ?3.0), height (105.4–118.3cm), per cent body fat (10.7–16.3), TBP (2.4–3.4kg), TBP per cent predicted for height (83.4–99.0), and BMC (469–626g). No significant increases were found in height SDS, TBP per cent predicted for age, or BMC SDS for age or height. Interpretation Malnourished children with quadriplegic CP showed significant increases in body fat and protein with gastrostomy tube feeding. No significant change in bone mineralization predicted for age or height was observed.     

Hybrid Pharmacologic and Ablative Therapy: A Novel and Effective Approach for the Management of Atrial Fibrillation

Hybrid Therapy for Atrial Fibrillation. Introduction: Maintenance of sinus rhythm in patients with recurrent atrial fibrillation is often difficult to achieve with pharmacologic therapy. Complex catheter ablative procedures are being developed, but efficacy and safety issues remain to be clarified. We hypothesized that combined pharmacologic and simple ablative therapies in a targeted subset of patients will improve success in the treatment of atrial fibrillation. Methods and Results: We identified 13 patients (mean age 61.5 ± 16.2 years) with atrial fibrillation who converted to electrocardiographic atrial flutter during antiarrhythmic drug treatment. Surface ECG suggested “typical” atrial flutter in 11 patients and “atypical” atrial flutter in 2. Intracardiac mapping and entrainment studies revealed 9 patients had counter-clockwise isthmus-dependent atrial flutter, and the remaining 4 had complex activation patterns, suggesting the presence of multiple wavefronts. All 9 patients with typical atrial flutter underwent successful ablation. None of the 4 patients with complex activation patterns had successful ablation. Patients were followed for recurrences of atrial arrhythmias via clinic visits, record review, and interviews. In patients who underwent successful ablation and continued on antiarrhythmic drugs, 88.9% remain in sinus rhythm after a mean follow-up of 14.3 ± 6.9 months (range 1 to 28). Conclusion: In patients who experience conversion of atrial fibrillation to atrial flutter during antiarrhythmic drug treatment, ablation and continuation of pharmacologic therapy is a safe and effective means of achieving and maintaining sinus rhythm.     

Nonuniform Anisotropy is Responsible for Age-Related Slowing of Atrioventricular Nodal Reentrant Tachycardia

Age-Related Slowing of AVNRT. Introduction : AV nodal reentrant tachycardia cycle length has been shown to he longer in the elderly population. Microfibrosis associated with aging producing nonuniform anisotropic conduction or changes in membrane ionic properties could explain this finding.
Methods and Results : Forty-five patients (33 women and 12 men) with typical AV nodal reentrant tachycardia were studied to analyze the effects of age on electrophysiologic characteristics of the tachycardia using high-density catheter mapping of the triangle of Koch. We classified patients into group A (age ≤ 45 years, mean [± SD] 32.7 ± 8.8, n = 27) and group B (age > 45 years, mean [± SD] 61.1 ± 10.2, n =18). Retrograde atrial activation was recorded during tachycardia by means of a 2-mm decapolar catheter at the His bundle, a quadripolar catheter at the high right atrium, a multipolar catheter (6 to 10 poles) in the coronary sinus, and a deflectable quadripolar catheter at the posterior triangle of Koch. The AH interval at the AV junction as well as HA intervals at several atrial sites were measured during tachycardia. HA intervals at all atrial recording sites except in the posterior triangle of Koch were significantly longer in group B, as well as the tachycardia cycle length (362 vs 329 msec, P = 0.01). The mean AH interval was prolonged by 24 msec in group B, but this difference did not reach statistical significance. A sequential pattern of retrograde atrial activation during tachycardia was more frequently recorded in group B.
Conclusions : Since the delayed activation to the atrium was heterogeneous, transverse nonuniform anisotropic conduction is a likely explanation of these age-related modifications of AV nodal reentrant tachycardia characteristics.