Spontaneous Accelerated Junctional Rhythm: An Unusual but Useful Observation Prior to Radiofrequency Catheter Ablation for Atrioventricular Node Reentrant Tachycardia in Young Patients

Between May 1990 and March 1995, 5 of 29 young patients (ages 4.2–25 years; median 14.1 years) undergoing RF ablation for atrioventricular node reentrant tachycardia (AVNRT) presented with spontaneous accelerated junctional rhythm (AJR) (CL = 500–750 ms), compared to 0 of 58 age matched controls undergoing RF ablation for a concealed AV accessory pathway (P = 0.004). In 3 of the 5 patients with AVNRT and AJR, junctional beats served as a trigger for reentry. During attempted slow pathway modification in the five patients with AVNRT and AJR, AVNRT continued to be inducible until the AJR was entirely eliminated or dramatically slowed. These 5 patients are tachycardia-free in followup (median 15 months; range 6–31 months) with only 1 of the 5 patients continuing to experience episodic AJR at rates slower than observed preablation. Episodic spontaneous AJR is statistically associated with AVNRT in young patients and can serve as a trigger for reentry. Successful modification of slow pathway conduction may be predicted by the elimination of AJR or its modulation to slower rates, suggesting that the rhythm is secondary to enhanced automaticity arising near or within the slow pathway.     

Observations From Intraatrial Recordings on the Termination of Electrically Induced Atrial Fibrillation in Humans

Background: The circulating wavelet hypothesis suggests that atrial fibrillation could terminate by either progressive fusion or simultaneous block of all wavelets. Methods: Intraatrial recordings from the right atrial free wall were made during procainamide induced (n = 8) or spontaneous (n = 7) termination of electrically induced atrial fibrillation in 14 patients. Atrial rate, mean magnitude squared coherence, and direction of activation during sequential electrograms were measured. Rate and coherence were calculated from the earliest point within 5 minutes prior to termination as well as from the 4-second interval just prior to termination. Results: Termination was directly to sinus rhythm (13 episodes) or to atrial flutter (2 episodes). For the eight procainamide induced terminations, rate decreased between the first measurement and the measurement just prior to termination, from 443 ±127 beats/ min to 322 ± 119 beats/min. For the seven spontaneous terminations, rate also decreased from 373 ± 119 beats/min to 323 ± 88 beats/min; however, a slight increase in atrial rate prior to termination was observed in three episodes. No specific patterns of atrial cycle lengths were seen during the final few seconds of fibrillation. No increase in coherence was observed. In seven episodes, recordings were made using orthogonal bipoles in the x, y, and z directions, allowing direction of activation of wavefronts to be measured. Three episodes showed multiple instances where direction of activation remained similar over several electrograms as we have previously reported for chronic fibrillation. However, no such instances precipitated termination in any of the seven episodes. Conclusions: Atrial fibrillation usually terminates directly to sinus rhythm and does so abruptly and without forewarning. While we and others have previously reported that the rate of atrial fibrillation decreases with procainamide infusion, a decrease in the rate of atrial fibrillation is not required for the rhythm to terminate and consequently may not be a part of the termination process at all. Coherence does not demonstrate a progressive increase in the organization of atrial fibrillation prior to termination. Lack of stabilization in the direction of activation of wavefronts in the final few seconds also fails to support fusion of wavefronts as the mechanism of termination of atrial fibrillation. Simultaneous block of all wavelets is consistent with, but not proven by our observations.     

Adding Gabapentin to a multimodal regimen does not reduce acute pain, opioid consumption or chronic pain after total hip arthroplasty

Background: Gabapentin (GPN) is effective in reducing post‐operative pain and opioid consumption, but its effects with regional anesthesia for total hip arthroplasty (THA) are not known. We designed this study to determine whether (1) gabapentin administration reduces pain and opioid use after THA using a multimodal analgesic regimen including spinal anesthesia; (2) pre‐operative administration of gabapentin is more effective than post‐operative administration. Methods: After REB approval and informed consent, 126 patients were enrolled in a double‐blinded, randomized‐controlled study. Patients received acetaminophen 1 g per os (p.o.), celecoxib 400 mg p.o. and dexamethasone 8 mg intravenously, 1–2 h pre‐operatively. Patients were randomly assigned to one of three treatment groups (G1: Placebo/Placebo; G2: GPN/Placebo; G3: Placebo/GPN). Patients received gabapentin 600 mg (G2) or placebo (G1 and G3) 2 h before surgery. All patients had spinal anesthesia [15 mg (3cc) of 0.5% hypobaric bupivacaine with 10 μg of fentanyl]. In the post‐anesthetic care unit, patients received gabapentin 600 mg (G3) or placebo (G1 and G2). On the ward, patients received acetaminophen 1000 mg p.o. q6h, celecoxib 200 mg p.o. q12h and a morphine PCA device. Patients were interviewed 6 months post‐surgery to determine the incidence and severity of chronic post‐surgical pain. Results: Mean±SD cumulative morphine (mg) consumption (G1=49.4±24.8, G2=47.2±30.1 and G3=56.1±38.2) at 48 h and pain scores at 12, 24, 36 and 48 h post‐surgery were not significantly different among the groups [G1 (n=38), G2 (n=38) and G3 (n=38)]. Side effect profiles were similar across groups. Six months after surgery, the number of patients who reported chronic post‐surgical pain (G1=10, G2=12 and G3=9) and the severity of the pain (G1=4.2±2.9, G2=4.1±2.2 and G3=4.9±2.2) did not differ significantly among the groups (P>0.05). Conclusions: A single 600 mg dose of gabapentin given pre‐operatively or post‐operatively does not reduce morphine consumption or pain scores in hospital or at 6 months after hip arthroplasty within the context of spinal anesthesia and a robust multimodal analgesia regimen.     

Cutaneous Alternariosis in an Adolescent Patient

Abstract:  Cutaneous alternariosis is a rare infection typically observed only in immunocompromised adults, but we report here that the infection can occur in apparently healthy adolescents. We saw a clinically healthy adolescent boy who presented with cutaneous alternariosis 6 weeks after suffering a laceration to his right ankle. Treatment with itraconazole resulted in significant improvement after 1 month.     

Intrathoracic Impedance Preceding Ventricular Tachyarrhythmia Episodes

Background: Heart failure is associated with ventricular tachyarrhythmias (VT/VF). Fluid accumulation during worsened heart failure may trigger VT/VF. Increased intrathoracic impedance has been correlated with fluid accumulation during heart failure. Implanted defibrillators capable of daily measures of intrathoracic impedance allow correlation of impedance with occurrence of VT/VF. We hypothesized that VT/VF episodes are preceded by decreases in intrathoracic impedance. The goal was to identify the relationship of intrathoracic impedance measured by implanted cardioverter defibrillators to the occurrence of VT/VF. Method: Implanted defibrillator follow‐up data were obtained retrospectively. Those with Medtronic OptiVol (Medtronic Inc., Minneapolis, MN, USA), storing averaged daily and reference impedance values, were reviewed for VT/VF episodes. Impedance changes in the week leading up to VT/VF were analyzed. Results: A total of 317 VT/VF episodes in a cohort of 121 patients’ follow‐up data were evaluated. Averaged daily intrathoracic impedance declined preceding 64% of VT/VF episodes, with an average decline of 0.46 ± 0.35 Ohms from the day before the VT/VF episodes. However, the mean values of the averaged daily and reference impedance did not change significantly. A novel measure, ΔTI, the sum of the daily differences between the averaged daily and reference impedance, was negative preceding 66% of VT/VF episodes (P < 0.001). The mean ΔTI was ?4.0 ± 1.3 Ohms, which was significantly lower than the theoretically expected value of zero Ohms (P < 0.01). Conclusion: (1) Averaged daily impedance declined preceding 64% of VT/VF episodes, but the overall decline was of small magnitude; (2) a novel measure, ΔTI, was negative preceding 66% of VT/VF episodes, and significantly below zero. (PACE 2010; 33:960–966)     

Lower extremity bone mineral density in children with congenital spinal dysfunction

Aim  To assess lower extremity bone mineral density (BMD) of children with congenital spinal dysfunction and examine factors that may influence BMD in this population. Method  Forty‐four children (25 females, 19 males) aged 6 to 18 years (mean 11y 11mo, SD 3y 6mo) with congenital spinal dysfunction (35 with myelomeningocele, seven with lipomas, one with sacral agenesis, one with caudal regression) were enrolled in the study. A health survey including ambulatory status, history of bladder augmentation, and history of fracture was administered. Each participant had a physical examination including Tanner stage and neurological level. Dual‐energy X‐ray absorptiometry scans of the lateral distal femur (LDF) and, when possible, lumbar spine were obtained. We reported LDF BMD results as z‐scores for three regions of interest (metaphyseal, metadiaphyseal, and diaphyseal). Univariable and multivariable analyses examined relationships between LDF BMD and the other variables. Results  BMD was significantly related to ambulatory status (14 non‐ambulatory, 15 partly ambulatory, 15 fully ambulatory) and neurological level (13 with low‐level lesions, 15 medium‐level, 16 high‐level) in the univariable analysis (p<0.01 for both in all three regions). Neither history of fracture, nor Tanner stage, nor history of bladder augmentation showed a significant relationship to BMD. The significance of ambulatory status and neurological level in the univariable analysis failed to persist in the multivariable analysis of this study with a small sample size. Interpretation  The LDF measurement proved to be a viable technique for assessing BMD in children with congenital spinal dysfunction. LDF BMD was sensitive to differences in three categories of ambulation. The overall influence of neurological level was not deemed as important as ambulation.     

Decreased fracture incidence after 1 year of pamidronate treatment in children with spastic quadriplegic cerebral palsy

Aim The aim of this study was to assess the rate of fracture before and after a 1‐year course of intravenous pamidronate in children with spastic quadriplegic cerebral palsy (CP) who had previously experienced fractures. Method Twenty‐five children (nine males, 16 females) with quadriplegic CP in Gross Motor Function Classification System (GMFCS) level IV or V who were treated with intravenous pamidronate for approximately 1 year were identified. All participants had previously experienced at least one non‐traumatic fracture. Each received 15 doses of pamidronate over a mean of 13.6 months. Post‐treatment observation ranged from 1 to 10 years 6 months (mean 4y 1mo). The fracture rate before and after commencement of treatment was calculated using the person‐years method. Results The participants had experienced a total of 86 fractures before treatment began, occurring over 280.6 person‐years, giving a fracture rate of 30.6% per year. During the post‐treatment observation period, totalling 107.5 person‐years, 8 of the 25 children experienced a total of 14 fractures. This fracture rate of 13.0% per year is a statistically significant decrease (p=0.02). Interpretation Pamidronate treatment lowered the rate of fracture, and a 1‐year course appears to provide a protective effect after treatment ends. For the majority of participants, this effect lasted 4 years or longer. However, a subset of children suffered a fracture soon after the drug was discontinued. In these children, a longer course of treatment appears to have been necessary.