Cutaneous Patch Research Articles

High concentration capsaicin for treatment of peripheral neuropathic pain: effect on somatosensory symptoms and identification of treatment responders

Background:Pain is usually assessed by spontaneous pain ratings. Time-dependent (brief attacks) or evoked (allodynia) phenomena, common in neuropathic pain, are not captured. To evaluate the overall effectiveness of a treatment, improvement of all sensory symptoms should be measured. Since the pattern of sensory abnormalities might hint at the underlying mechanisms of pain, this baseline information may aid in predicting the treatment effect. Data on sensory neuropathic abnormalities (painDETECT questionnaire) were analyzed aiming to (1) evaluate the frequency of neuropathic symptoms in different peripheral neuropathic pain syndromes, (2) assess the effect of capsaicin 8% patch on neuropathic symptoms and (3) identify treatment responders based on baseline values.Methods:Data analysis of a prospective 12 week non-interventional trial in peripheral neuropathic pain treated with capsaicin 8% cutaneous patch. Average pain intensity during the past 24 hours, pain descriptors and qualities of neuropathic pain were assessed to characterize the patients’ sensory symptoms at baseline and to document changes.Results:(1) Characteristic symptoms of neuropathic pain were present in all peripheral neuropathic pain syndromes, but frequencies varied in the individual syndromes. (2) Topical capsaicin 8% treatment significantly reduced the overall pain intensity and resulted in a reduction of sensory abnormalities. (3) Short disease duration predicted a better treatment effect. High painDETECT scores, the presence of burning and pressure-evoked pain were weakly associated with treatment response.Conclusions:Topical capsaicin 8% treatment effectively reduced sensory abnormalities in peripheral neuropathic pain. The association of sensory symptoms and treatment response aids in understanding the mechanism of action of high concentration capsaicin. It is, however, not possible to use sensory symptom patterns to predict treatment response to capsaicin on an individual level.Limitations:Completion of painDETECT was optional and therefore data was not available for all patients. Further studies for confirmation of these results are needed.

Metal Allergy Screening Prior to Joint Arthroplasty and Its Influence on Implant Choice: A Delphi Consensus Study Amongst Orthopaedic Arthroplasty Surgeons

PurposeThis study was undertaken to obtain a consensus amongst joint arthroplasty experts with regards to metal allergy screening prior to joint arthroplasty and the choice of implant in patients with potential metal allergy.Materials and MethodsA web based Delphi consensus study was used including orthopaedic surgeons that had previously published on the topic of knee, hip or shoulder arthroplasty. Two rounds of questionnaires were sent via electronic mail. Consensus was considered reached if agreement was 60% or higher.ResultsEighteen surgeons responded to the first and 17 to the second round of questionnaires. There was consensus that patients having metal arthroplasty surgery should not be routinely questioned about metal allergy prior to surgery. There was consensus that patch testing is not necessary even if metal allergy is suspected. Most respondents agreed in proceeding with cobalt chromium or stainless steel implant in patients suspected of metal allergy regardless of the results of cutaneous patch testing.ConclusionsThis consensus study suggests that routine metal allergy screening prior to joint arthroplasty is not essential. The use of traditional cobalt chromium/stainless steel implants is recommended regardless of the patient's metal allergy status based on expert opinion through this study.

Genetic markers associated with progression in early mycosis fungoides

Mycosis fungoides (MF) is a rare, but potentially devastating malignancy. It classically presents with cutaneous patches and plaques and can progress to tumours on the skin with lymph node, blood and visceral involvement. While most patients with MF have a relatively benign disease course, a subset of patients will develop progressive disease that is often fatal. The aim of this study was to identify genetic markers in early MF limited to the skin (stages IA-IIA) that distinguish those patients who will have progressive disease from those who will not, so that early appropriate treatment may be instituted. The study includes 18 patients who were diagnosed with early stage MF at the time of biopsy and had follow-up to determine which patients developed progressive disease. RNA was extracted from skin biopsy specimens and analysed for expression of CD3, FOXP3, IFNγ, Interleukin (IL)-4, IL-13, KIR3DL2, MICB, PLS3 and STAT4 by quantitative real-time polymerase chain reaction. Reduced expression of FOXP3 and STAT4 and increased expression of IL-4 relative to CD3 expression levels were significantly associated with MF progression. Further studies will be needed to fully assess the usefulness of these genetic markers to predict disease progression and guide treatment options in patients diagnosed with early MF.

Treatment of peripheral neuropathic pain by topical capsaicin: Impact of pre‐existing pain in the QUEPP‐study

BackgroundThis study evaluates the impact of the duration of pre-existing peripheral neuropathic pain on the therapeutic response to the capsaicin 8% cutaneous patch.MethodsThe non-interventional QUEPP (QUTENZA – safety and effectiveness in peripheral neuropathic pain) study evaluated the effectiveness of Qutenza™ in 1044 non-diabetic patients with peripheral neuropathic pain, who received a single application. Follow-up visits were scheduled at weeks 1–2, 4, 8 and 12. A pre-defined co-analysis of changes in average pain intensity was performed based on the duration of pre-existing pain.ResultsIn patients with pre-existing pain for <6 months, the mean relative change of the numeric pain rating scale score on days 7–14 to week 12 versus baseline was −36.6% [4.6 standard error of the mean (SEM); n = 105], −25.1% (1.9 SEM; n = 311) in patients with pain duration of 6 months to 2 years, −22.3% (1.6 SEM; n = 391) in patients with pain for >2–10 years, and −19.2% (2.6 SEM; n = 99) in patients with pain for >10 years. Thirty percent and 50% responder rates were 61.7% and 39.3% in patients with pre-existing pain for <6 months, 42.3% and 23.3% in patients with pain for 6 months to 2 years, 40.9% and 21.6% in patients with pain for >2–10 years, and 32.3% and 14.1% in patients with pain for >10 years.ConclusionsThe highest treatment response to the capsaicin 8% cutaneous patch was observed in patients with a history of pre-existing peripheral neuropathic pain of less than 6 months, suggesting that early initiation of topical treatment might be indicated.

Cutaneous pigmented patches

Cutaneous pigmented patches

Prospective, non-interventional study on the tolerability and analgesic effectiveness over 12 weeks after a single application of capsaicin 8% cutaneous patch in 1044 patients with peripheral neuropathic pain: first results of the QUEPP study

Background:Reversible defunctionalisation of nociceptors by the TRPV1 agonist capsaicin in high concentration is an emerging new concept for the treatment of peripheral neuropathic pain.Objectives:The capsaicin 8% cutaneous patch with a long-lasting effect for up to 3 months after a single application is available in Germany by prescription since October 2010. The aim of this study was to monitor its usage and therapeutic performance in clinical practice.Methods:Patients had a single patch application with up to 4 patches and were followed up after 7–14 days, 4, 8, and 12 weeks. Average pain intensity (NPRS-11), pain attacks, neuropathy symptoms, sleep parameters, quality of life, working capacity and concomitant neuropathic pain medication were assessed during at least two visits.Results:A total of 509 females (48.8%; effectiveness population N = 1044) and 531 males (50.9%) were included; the mean age was 61.2 ± 14.4 (SD) years. Postherpetic neuralgia was the most frequent diagnosis (31.9%), followed by postsurgical neuralgia (22.8%), post-traumatic neuropathy (12.4%), polyneuropathy (14.3%), and mixed pain syndromes (16.6%). Thirty and 50% responder rates were 42.7% and 23.7%, respectively, with a mean relative reduction of pain intensity during weeks 1–12 of 24.7% (1.1 SEM) and significant improvements in pain attacks, sleep duration and sleep quality, while the consumption of opioids and antiepileptics decreased significantly. In 106 patients (10.0%; safety population n = 1063) 146 adverse drug reactions (ADRs) were reported, mainly application site reactions (erythema, pain). A total of 27 serious ADRs were documented in 17 patients (1.6%).Conclusions:Analgesic treatment of peripheral neuropathic pain with the capsaicin 8% cutaneous patch is safe and effective.Limitations:The study did not include a control group; therefore, a comparison of the results with that of therapeutic alternatives is not justified.

Mycosis Fungoides and Head and Neck Malignancies

Mycosis fungoides is a cutaneous T-cell lymphoma characterized by cutaneous patches and plaques that may progress to hematologic involvement and Sezary syndrome. Second primary tumors have been described in the literature without emphasis on head and neck neoplasms. We report two cases of head and neck malignancies in patients with a history of mycosis fungoides. A PubMed literature search was performed and results were reviewed. Second primary tumors in the head and neck have been reported in the nose and nasal cavity, sinuses, oral cavity, pharynx, hypopharynx, larynx, tracheobronchial tree, thymus, and skin. We present cases of submandibular mucoepidermoid carcinoma and papillary thyroid carcinoma in patients with a history of mycosis fungoides. Mycosis fungoides may confer increased risk of developing a second primary neoplasm of the head and neck. Possible mechanisms may include immunosuppression inherent in treatment modalities, the disease course of mycosis fungoides, or related genetic mutations.

Split cord malformation with dorsally located bony spur: Report of four cases and review of literature

Split cord malformations (SCM) with a dorsally located bony spur are a very rare entity. The authors report a series of four such cases. The literature is reviewed regarding the pathogenesis and management of this uncommon variant of SCM. The presenting features include – scoliosis with motor and autonomic dysfunction (n = 1), scoliosis with cutaneous patch (n = 1), hypertrichotic area (n = 1), and motor deficits alone (n = 1). The location of spur was thoracic and lumbar in two patients (50%) each. Low-lying conus was present in three patients. Long segment syrinx was present in one patient. With respect to the bony anomalies, two patients had a hypertrophied posterior arch (HPA) and one patient had a dysraphic spine. All patients underwent surgical excision of the spur with detethering, if a low-lying conus was present. Two patients developed transient worsening of the neurological status after surgery which recovered at the time of the last follow-up; in both these patients, there was a HPA and a low-lying conus. Surgical excision of the spur with detethering of filum, in cases of low-lying conus, is the treatment of choice. Risk of post-operative worsening of the neurological status is increased in cases in which there is concomitant presence of HPA.

Characterization of the DNA Copy-Number Genome in the Blood of Cutaneous T-Cell Lymphoma Patients

Cutaneous T-cell lymphoma (CTCL) is a heterogeneous non-Hodgkin's lymphoma that may variably involve the skin, lymph nodes, and peripheral blood. Malignant burden ranges from cutaneous patches and plaques with little evidence of blood involvement to erythroderma often in association with frank leukemia, as in Sézary syndrome. Toward a better understanding of the pathogenesis of this CD4+ T-cell malignancy, we conducted a high-resolution genomic analysis combining DNA (23 samples) and mRNA (12 samples) data of peripheral blood isolates from CTCL patients across a spectrum of stages. Strikingly, even patients with limited involvement, e.g., normal CD4 counts, contained significant copy-number alterations. Defining genomic characteristics of CTCL blood involvement included gains on 8q and 17q, and deletions on 17p and chromosome 10. A consensus analysis of 108 leukemic CTCL samples demonstrated global similarities among patients with varied blood involvement, narrowing 38 of 62 loci. Toward an annotated framework for in vitro testing, we also characterized genomic alterations in five CTCL cell lines (HH, HUT78, PNO, SeAx, and Sez4), revealing intact core features of leukemic CTCL. Together, these studies produce the most comprehensive view of the leukemic CTCL genome to date, with implications for pathogenesis, molecular classification, and potential future therapeutic developments.

Terra firma-forme dermatosis

Terra firma-forme dermatosis is characterized by 'dirty' brown-grey cutaneous patches and plaques that can simply be eradicated by forceful swabbing with alcohol pads. The pathogenesis has been attributed to abnormal and delayed keratinization. Although affected patients present with typical lesions, the disorder is not well-known by dermatologists. In this report, we describe two patients with terra firma-forme dermatosis in the setting of xerosis cutis and atopic dermatitis. From a clinical point of view, we lay emphasis on its unique expression and diagnosis/treatment. From a histological perspective, we highlight its resemblance to dermatosis neglecta and speculate on the role of 'neglect' in a patient with seemingly adequate hygiene. The role of urea containing emollients in the development of this disorder remains to be determined.

How Does an Anabolic/Androgenic Steroid Get Banned from Sport Competition?

What is an androgen (anabolic-androgenic steroid)? Most would state that it is a derivative of the major sex steroid in men and most mammals, testosterone (T). Others might answer in the more generic sense: any compound that is an agonist (or partial agonist) at the androgen receptor (AR). There are seemingly enough forms of T activity available to satisfy the needs of the medical population with oral, buccal, cutaneous patches (really, drug delivery devices) and gels, injectables of various durations (days to months), and implantable forms with a duration of action of 6 months or more. Why then are some arcane designer steroids produced? It seems that performance enhancement for human (and at least equine) athletes provides the backbone for the design of new anabolic steroids to circumvent the sophisticated testing procedures that surround major national and international competitions [World Anti-Doping Agency (WADA), www.wada.ama.org]. In the 1940s and 1950s, many pharmaceutical companies evaluated a myriad of compounds with purported anabolic activity searching for those that had anabolic (at muscle) activity without the more androgenic activities. It was to little avail given that there is but one AR, albeit with a greater affinity for dihydrotestosterone than for T itself (1). Arcane T chemistry produced many compounds that had sat on shelves for years without any clinical trials for evaluation for human or veterinary use or commercial promotion. In the future, the concept of selective AR agonists may come to play a much more prominent role. Such compounds may selectively produce the beneficial effects of androgens on musculoskeletal mass and strength without the androgenic adverse events (2). Clandestine laboratories seeking to make a product to give an edge to athletes began to screen compounds for their anabolic/androgenic activities with the proviso that the compound and its metabolites be invisible to the WADA screening protocol, www.wada-ama.org. It appeared quite straightforward to begin with the steroid structure of testosterone, add multiple decorations to the various carbon atoms, test in vitro with various cell lines that contain the AR linked to an objective outcome, for example, AR nuclear translocation or myogenic activity (2). Then comes the nefarious part: all certified antidoping laboratories have libraries of chromatography/mass spectroscopy (MS)/MSfragments, andeachanabolic/androgenic steroid has its own unique signature. The skill is to find a compound active at the AR, but that is not yet in the library. Is this just an academic exercise in steroid biochemistry? I think not, given the example of tetrahydrogestrinone (THG). THG had been invisible to the antidoping laboratories until a sample of pure THG was presented to an antidoping lab. It had been synthesized by an underground laboratory and likely underwent enough testing (in vitro and in vivo) to determine its anabolic/androgenic activity and that it could not be detected by the then extant WADA testing procedure. However, within a week of obtaining that pure sample of THG, the University of California at Los Angeles (UCLA) Olympic Analytic Laboratory was able to devise a test for this compound and its metabolic products (3). This task was later verified by the synthesis of THG and characterized by MS and nuclear magnetic resonance spectroscopy. The UCLA laboratory developed and verified sensitive and specific methods for the rapid screening of urine samples by liquid chromatography/tandem MS, both in the natural state and with trimethylsilyl ether-oxime derivatives (as is done in the standard anti-

Clinical challenge: cutaneous Kaposi's sarcoma of the lower extremity*

Kaposi's sarcoma (KS) typically presents as multiple bilateral cutaneous patches or plaques of the lower extremities. This malignancy, however, can evolve with atypical presentation masquerading as a chronic wound. Lesions can mimic venous stasis ulcers, arterial insufficiency, vascular ulcers or chronic-infected wounds. With acquired immune deficiency syndrome (AIDS)-associated KS, lesions are even more widespread, and can affect the respiratory tract, lymph nodes, gastrointestinal tract, spleen, liver and, rarely, bone. As the initial diagnosis of KS is generally determined clinically, a high index of suspicion is necessary for all patients with a known or suspected history of HIV/AIDS. Tissue biopsy with histological analysis is essential for all wound types in this patient subset, regardless of wound presentation. The purpose of this report is to review the pathogenesis as well as the typical and atypical presentations of KS with an example of a diagnostic dilemma.

Cutaneous patch testing may be a safe and useful method for confirming a culprit antiepileptic associated with DRESS syndrome;

Cutaneous patch testing may be a safe and useful method for confirming a culprit antiepileptic associated with DRESS syndrome;

Pharmacokinetic Analysis of Capsaicin After Topical Administration of a High-Concentration Capsaicin Patch to Patients With Peripheral Neuropathic Pain

Capsaicin, a pungent compound in chili peppers, is a highly selective agonist for the transient receptor potential vanilloid 1 receptor expressed in nociceptive sensory nerves. A high-concentration (640 microg/cm2) capsaicin patch, designated NGX-4010, is in clinical evaluation for the management of peripheral neuropathic pain. To determine systemic capsaicin exposure after single 60- or 90-minute NGX-4010 applications, plasma samples were collected from 173 patients with postherpetic neuralgia (PHN), painful human immunodeficiency virus-associated neuropathy (HIV-AN), and painful diabetic neuropathy (PDN). The percentages of patients with quantifiable levels of capsaicin at any time point were 31% for PHN (30 of 96), 7% for HIV-AN (3 of 44), and 3% for PDN (1 of 33). The maximum plasma concentration observed in any patient was 17.8 ng/mL. Due to the limited number of quantifiable levels, a population analysis was performed to characterize the pharmacokinetics (PK) of capsaicin. Plasma concentrations were fitted adequately using a 1-compartment model with first-order absorption and linear elimination. Capsaicin levels declined very rapidly, with a mean population elimination half-life of 1.64 hours. Mean area under the curve and C max values after a 60-minute application were 7.42 ng x h/mL and 1.86 ng/mL, respectively. Only a few correlations between calculated PK parameters and patient characteristics were observed. Duration and area of application of the patch were detected as significant covariates explaining the PK of capsaicin. Ninety-minute applications of NGX-4010 resulted in capsaicin area under the curve and Cmax values approximately 1.78- and 2.15-fold higher than those observed in patients treated for 60 minutes. Treatment on the feet (patients with HIV-AN and PDN) produced far lower systemic exposure than treatment on the trunk (patients with PHN). Finally, larger treatment areas were associated with statistically higher Vc/F values. The low systemic exposure and very rapid elimination half-life of capsaicin after NGX-4010 administration are unlikely to result in systemic effects and support the overall safety profile of this investigational cutaneous patch.

Glomerulocystic kidney disease in hypomelanosis of Ito

Hypomelanosis of Ito (incontinentia pigmenti type I) was first described as a disorder characterized by unusual unilateral or bilateral cutaneous macular hypopigmented whorls, streaks and patches. Subsequently, neurologic, skeletal and ocular involvement were described. Kidney involvement has been reported only exceptionally. Here, we describe the case of a male infant with hypomelanosis of Ito with a prenatal diagnosis of bilateral enlargement of the kidneys, decreased corticomedullary differentiation and cysts located in the cortical and subcapsular regions. These findings were confirmed postnatally. The skin examination showed hypopigmented linear and round diffuse lesions located on the right leg and the arms. Ophthalmological examination showed anterior capsular and posterior subcapsular cataract of the left eye. Renal biopsy was characteristic of glomerulocystic kidney disease, whereas the skin biopsy confirmed the clinical diagnosis of hypomelanosis of Ito. Four other cases of kidney disease in hypomelanosis of Ito have been reported, including two cases characterized by cystic renal changes, indicating that gene abnormalities that cause hypomelanosis of Ito may also impair normal renal development, causing renal cystic changes.

The H syndrome: A genodermatosis characterized by indurated, hyperpigmented, and hypertrichotic skin with systemic manifestations

The association of cutaneous hyperpigmented, hypertrichotic, and indurated patches associated with hearing loss, short stature, cardiac anomalies, hepatosplenomegaly, scrotal masses, and hypogonadism has not, to our knowledge, been previously recognized as a disease entity. We describe 10 patients with the above-mentioned findings. Patients were clinically examined and extensive laboratory evaluation was performed. We describe 10 patients from 6 Arab consanguineous families with hyperpigmented, hypertrichotic, and indurated cutaneous patches involving the middle and lower parts of their bodies. In addition, patients displayed short stature, sensorineural hearing loss, cardiac anomalies, hepatosplenomegaly, and scrotal masses. Laboratory evaluation revealed growth hormone deficiency and hypergonadotropic hypogonadism with azoospermia. Cutaneous histopathologic examination showed hyperpigmentation of the basal layer with seborrheic-keratosis-like acanthosis, histiocytic infiltration, and a perivascular mononuclear infiltrate with plasma cells and mast cells throughout the dermis and subcutaneous fat. Comparison with several patients, recently reported in the medical literature, with similar cutaneous findings is made. Laboratory evaluation in some patients was incomplete because of lack of cooperation. We suggest that our patients represent a novel multisystemic autosomal recessive inherited disorder. We call this constellation of symptoms the "H syndrome."

Efficacy of transesophageal defibrillation in ventricular fibrillation of long duration

Introduction Increasing duration of ventricular fibrillation (VF) is associated with a higher risk of ineffective resuscitation. In addition, precountershock chest compression can influence defibrillation success. Transesophageal defibrillation may increase defibrillation success because of the proximity of the esophagus to the heart. We evaluated the efficacy of transesophageal defibrillation compared with standard transthoracic defibrillation after long episodes of VF. Methods Defibrillation success after 10 minutes of untreated VF was evaluated in 12 sheep randomized into 2 groups: (group A) in 6 sheep, up to 3 transthoracic shocks were applied, followed by up to 3 transesophageal shocks (first shock: 150 J, second and third shocks: 200 J). (group B) In 6 sheep, 2 minutes of precountershock chest compression preceded the defibrillation shocks. Truncated biphasic shocks were delivered between a sternal and an apical patch electrode for transthoracic defibrillation and between an esophageal and a cutaneous patch electrode for transesophageal defibrillation. Results In group A with no precountershock chest compression, external defibrillation failed despite shocks with maximum energy (200 J) in all 6 sheep. Transesophageal defibrillation was successful in 3 sheep (50%). In group B with precountershock chest compression, external defibrillation failed in all 6 sheep. Transesophageal defibrillation was successful with the first shock in all 6 sheep. Conclusions Transesophageal defibrillation may terminate VF of long duration that is refractory to standard defibrillation. Precountershock chest compression may increase transesophageal defibrillation success.

Nickel Allergy in Interatrial Shunt Device-based Closure Patients

The possibility of nickel toxicity has been raised with interatrial shunt closure devices constructed of nitinol. This study is aimed to assess the potential adverse symptoms in terms of incidence, duration, and significance, in patients with interatrial shunt and nickel allergy who underwent nitinol device-based closure. We prospectively enrolled 46 consecutive patients (mean age 35 +/- 28.8 years, 30 female) over a 12-month period referred to our center for catheter-based closure of interatrial shunts. Patients were investigated for previous hypersensivity to nickel and were required to test potential nickel allergy with cutaneous patch test (TRUE test) before device implantation. Routinely, clinical visit with laboratory examinations, and TTE were scheduled at 1, 6, and 12 months. Nine patients (19.5%, mean age 31.3 +/- 13.2 years) had proved symptomatic and instrumental nickel allergy as showed by cutaneous patch skin test but preferred to be implanted. All patients underwent successful transcatheter closure with an immediate occlusion rate of 100% without intraoperative complications. Between the 2nd and 3rd postoperative day, 8 out of 9 patients developed a sort of 'device syndrome' that included concurrent chest discomfort, exertional dyspnea and asthenia, and mild leukocytosis. The syndrome was treated with Prednison and Clopidogrel and in all was resolved after 1-week therapy. Interestingly, none of the patients without nickel allergy developed postclosure symptoms (P < .001). In conclusion, nickel allergy is still a problematic issue in patients scheduled for transcatheter closure of intracardiac shunts; however, our brief study suggests that nickel allergy is not per se a contraindication to nitinol device closure.

Comparison of four clinically used external defibrillators for transesophageal defibrillation

Defibrillation thresholds (DFT) are lower when using biphasic instead of monophasic shock waveforms. In addition, transesophageal defibrillation can decrease the defibrillation threshold compared to thransthoracic defibrillation due to a different shock vector. We compared the defibrillation thresholds of a monophasic and three biphasic defibrillators in transesophageal defibrillation. Ventricular fibrillation was electrically induced in 12 domestic pigs. Transesophageal defibrillation was performed between two cutaneous patch electrodes and one esophageal electrode. The lowest energy level with successful defibrillation was defined as the DFT. Using four commercially available defibrillators, DFTs were determined for monophasic, truncated exponential biphasic and rectilinear biphasic shock waveforms. DFTs for biphasic transesophageal shocks were significantly lower than for monophasic shocks, reducing DFT to about 50%. There was no significant difference between the three biphasic defibrillators with regard to DFT. The choice of shock waveform can further decrease the already low DFT in transesophageal defibrillation. Similar to transthoracic defibrillation, biphasic shock waveforms yield lower DFTs in transesophageal defibrillation compared to monophasic shocks. The use of different biphasic waveforms does not seem to have a major effect on DFT in transesophageal defibrillation.

Potential benefit of transesophageal defibrillation: an experimental evaluation

Introduction Because of the proximity of the esophagus to the heart, transesophageal defibrillation might increase defibrillation success. We assessed the defibrillation threshold (DFT) of transesophageal defibrillation compared with standard transthoracic defibrillation. Methods Defibrillation success and DFTs were determined in 22 female pigs with high (68 ± 4 kg, n = 12) or low body weight (39 ± 1 kg, n = 10). After induction of ventricular fibrillation, biphasic shocks were delivered between two cutaneous patch electrodes (sternal and apical position) or between an esophageal and two cutaneous patch electrodes in a sternal and apical position. The esophageal electrode was integrated into a latex sheath covering a standard transesophageal echocardiography probe. Results In 5 of 12 pigs with high body weight, external defibrillation failed despite 3 consecutive 200-J shocks, whereas subsequent transesophageal defibrillation was successful with the first shock. In the remaining 7 pigs, a more than 50% reduction in DFT was obtained with transesophageal defibrillation compared with standard biphasic external defibrillation (67 ± 27 vs 164 ± 23 J, P < .001). Pigs with lower body weight were successfully defibrillated by both transthoracic and transesophageal shocks. The DFT in pigs with low body weight was significantly lower using transesophageal defibrillation compared with transthoracic shocks (65 ± 15 vs 99 ± 38 J, P < .05). Conclusions In this animal model, nonresponders to standard external defibrillation could successfully be defibrillated via an esophageal-cutaneous electrode configuration. Overall, an almost 50% DFT reduction was achieved by transesophageal defibrillation. Transesophageal defibrillation may provide an additional tool for terminating VF, which is refractory to external defibrillation, eg, in patients with very high body weight.