Feasibility and Safety of Using an Esophageal Protective System to Eliminate Esophageal Thermal Injury: Implications on Atrial-Esophageal Fistula Following AF Ablation

Background: Ablation for atrial fibrillation (AF) requires energy delivery in close proximity to the esophagus (Eso) which has accounted for the LA-Eso fistula, a rare but life-threatening complication.
Purpose: We evaluated an Eso cooling system to protect the Eso during RF ablation.
Methods and Results: An in vitro heart-Eso preparation was initially used to test a temperature-controlled fluid-circulating system (EPSac [esophageal protective system]—RossHart Technologies Inc.) and an expandable compliant Eso sac during cardiac RF delivery (4 mm tip, perpendicular to the heart, 15 g pressure) at 25, 35, and 45 W, 100 ± 5 Ω for 30 seconds with the EPSac at 25, 15, 10, and 5°C. All cardiac lesions were transmural. Eso thermal injury could only be avoided with the EPSac at 10 and 5°C. The system was then tested in 6 closed chest dogs, each receiving 12 RFs (LA aiming at the Eso) for 30 seconds: without EPSac (control) at 35 W (1 dog); at 45 W with EPSac at 25°C (1 dog), 10°C (2 dogs), and 5°C (2 dogs). The EPSac volume was intentionally increased to displace the Eso toward the LA (2 dogs 5 and 10°C). Eso injured control and EPSac at 25°C; Eso spared EPSac at 5 and 10°C, without Eso displacement. Shallow external Eso injury noted when intentionally displacing the Eso toward the LA.
Conclusions: The EPSac spares the Eso from collateral thermal injury. It requires circulating fluid at 5 or 10°C and a compliant sac to avoid displacement of the Eso. Its safety and efficacy remain to be demonstrated in patients undergoing AF ablation.     

Relationship Between Catheter Forces, Lesion Characteristics, Popping, and Char Formation: Experience with Robotic Navigation System

Introduction: Popping, char and perforation are complications that can occur following catheter ablation. We measured the amount of grams (g) applied to the endocardium during ablation using a sensor incorporated in the long sheath of a robotic system. We evaluated the relationship between lesion formation, pressure, and the development of complications.
Methods: Using a robotic navigation system, lesions were placed in the left atrium (LA) at six settings, using a constant duration (40 seconds) and flow rate of either 17 cc/min or 30 cc/min with an open irrigated catheter (OIC). Evidence of complications was noted and lesion location recorded for later analysis at necropsy.
Results: Lesions using 30 Watts (W) were more likely to be transmural at higher (>40 g) than lower (<30 g) pressures (75% vs 25%, P < 0.001). Significantly higher number of lesions using >40 g of pressure demonstrated popping and crater formation as compared with lesions with 20–30 g of pressure (41% vs 15%, P = 0.008). A majority of lesions placed using higher power (45 W) with higher pressures (>40 g) were associated with char and crater formation (66.7%). No lesions using 10 g of pressure were transmural, regardless of the power. Lesions placed with a power setting less than 35 W were more likely to result in relative sparing of the endocardial surface than lesions at a power setting higher than 35 W (62% vs 33.3%, P = 0.02) regardless of the pressure.
Conclusions: When using an OIC, lower power settings (≤35 W) and lower/medium contact pressure were more likely to show a relative spared endocardial surface. Overall, contact pressure between 20 g and 30 g and a power setting of 40 W appeared to achieve transmurality by preserving safety.     

LOCAL MICROWAVE HYPERTHERMIA AND INTRAVESICAL CHEMOTHERAPY AS BLADDER SPARING TREATMENT FOR SELECT MULTIFOCAL AND UNRESECTABLE SUPERFICIAL BLADDER TUMORS

Purpose

The role of a combined regimen of local hyperthermia and topical chemotherapy in patients with multifocal and recurrent superficial bladder tumors not curable by transurethral resection was evaluated in a neodjuvant organ sparing clinical study.

Materials and Methods

A total of 19 patients with multifocal, superficial grades 1 to 3 bladder tumors that recurred after intravesical chemoprophylaxis or immunoprophylaxis underwent local combined administration of microwave induced hyperthermia and intravesical chemotherapy as a debulking approach. Due to extensive superficial involvement of the bladder walls complete transurethral resection of all tumors seemed technically unfeasible in all cases and radical cystectomy was considered the treatment of choice. Endovesical hyperthermia at 42.5 to 46C was delivered using the SB-TS 101 system,* based on a microwave transurethral applicator that irradiates the bladder filled with a circulating solution of mitomycin C. Patients underwent 8 weekly 1-hour sessions on an outpatient basis without anesthesia. When possible, after treatment patients underwent transurethral resection of residual tumors and all suspicious areas.*Boston Scientific Corp., Natick, Massachusetts.

Results

After treatment transurethral resection appeared to be feasible and curative in 16 patients (84%). Histological study revealed complete and partial responses in 9 (47%) and 7 (37%) cases, respectively. Due to extensive residual tumors radical cystectomy was performed in 3 patients (16%). At a median 33-month followup 8 superficial transitional tumor recurrences were documented and easily eradicated by transurethral resection or laser therapy in patients in whom the bladder had been saved.

Conclusions

Microwave induced hyperthermia combined with intravesical mitomycin C seems to be a feasible, safe and elective approach for conservative treatment of multifocal and recurrent superficial bladder tumors when other treatment strategies have failed.     

Ethics and animal issues in US medical education

Increasing public and regulatory agency concern about a variety of animal protection issues that affect the field of medicine have made these issues increasingly relevant to medical school curricula. The purpose of this study was to assess the availability and forms of medical school training relating to ethical, conceptual, and societal concerns in the use of animals within the field of medicine and the perceived need for such training.
Questionnaire surveys were mailed to the Deans of the 125 accredited US medical schools, and completed by Deans or their designees within the same medical institution. Questionnaire recipients were informed that results would be compiled in a fashion that did not identify specific individuals or institutions.
Survey responses were obtained from 84 medical institutions (67% response). Sixty respondents (71%) indicated that their medical school offered or sponsored some type of activity related to ethical and conceptual concerns in the use of animals in medical research and training. Most schools (43) offered informal discussions/seminars relating to these issues, but nine schools offered full formal courses with up to 15 lectures on these topics. Programme content and perceived need for additional instruction varied greatly amongst respondents.
The results suggest a wide diversity amongst US medical schools in the availability and perceived importance of medical school training relating to ethical and conceptual concerns in the uses of animals in medicine. It is proposed that instruction in these areas be pursued with more concerted efforts to address the growing body of knowledge about non-human beings and the ethical implications of such knowledge.     

Troubleshooting Implantable Cardioverter Defibrillator System Malfunctions: The Role of Impedance Measurements

High impedance measurements may be used to troubleshoot ICD system malfunction. In four different cases a defective system was identified or confirmed by an abnormal impedance: two secondary to lead fractures, one to an adapter faulty connection, and one to a hose set-screw connection. This led to further diagnostic procedures that ultimately localized the difficulty. Though the problems with ICD may be of diverse origins, routine use of impedance measurement for the troubleshooting of these systems may serve as an early sign of malfunction and would point the need for further investigation.     

Permanent Form of Junctional Reciprocating Tachycardia Involving an Atrio-Hisian Accessory Pathway: Electrophysiologic and Histologic Correlations

We present clinical, electrophysiologic and morphologic correlations of a patient with a permanent form of junctional reciprocating tachycardia, who died from a lung tumor. At electrophysiologic study, the tachycardia circuit was suspected to involve an atrio-Hisian accessory pathway antegradely and the AV node retrogradely; a ventriculo-atrial accessory pathway was excluded. Pathologic examination revealed a right-sided atrio-Hisian accessory pathway and an area of abnormal dispersion in the distal His bundle fibers. This case is consistently different from another previously reported case in which a concealed, serpiginous, septal atrioventricular accessory pathway was demonstrated by anatomic examination. Thus, different substrates seem to be responsible for the permanent form of junctional reciprocating tachycardia.     

Sleep-related painful erections: Clinical and polysomnographic features

The aim of this study was to describe the clinical characteristics and the polysomnographic findings of a sample of patients affected by sleep-related painful erections (SRPE). In a 6-y period 18 patients were diagnosed as having SRPE. The mean age at the onset of the disease was 39.8±11.6 y and the mean duration of SRPE was 5.4±3.5 y. According to ICSD criteria, about 60% of patients had a severe form of the disease. None of the patients met any DSM IV Axis-I and Axis-II diagnoses. Twelve patients complained of excessive daytime sleepiness. SRPE patients, compared to age-matched controls, showed a reduced sleep efficiency, an increased wake after sleep onset and a reduced percentage of REM sleep. This study confirms that in SRPE there are no clear predisposing factors, no familial pattern, but REM sleep fragmentation. Concerning the pharmacological treatment, in the history of patients, propranolol and paroxetine, but not amitriptiline and lorazepam, showed a temporary efficacy in some patients.