Modification of Atrioventricular Conduction Using a Combined Laser-Electrode Catheter

Ablation of the AV junction is an accepted technique for the management of selected supraventricular tachyarrhythmias. Radiofrequency ablation appears to be safe and effective for AV junction ablation in most patients, but the need for firm tissue contact may make it less effective for ventricular tachycardia and certain ectopic atrial tachycardias. Laser energy can also be delivered through a catheter, and thus it may be an attractive alternative energy source for ablation. A new laser-electrode catheter was developed for modification of conduction through the AV node as a model for ablation of an arrhythmia substrate. A window for delivery of continuous-wave Nd:YAG laser energy was placed between the two electrodes of a bipolar electrode catheter. In vitro studies using a matrix of power versus time were performed to determine the energy that would create lesions of the appropriate size in vivo. Using this information, advanced AV block was successfully created in 16 of 17 dogs (94%) with the laser-electrode catheter. Advanced AV block was successfully created in all four dogs in the chronic study, and it persisted for 1-24 weeks of follow-up until sacrifice of the animals. Histologic examination demonstrated discrete thermal damage at the AV junction with no instances of septal perforation in the acute studies or progressive necrosis in chronically maintained dogs. Advanced AV block may be produced consistently and safely in dogs using a combined laser-electrode catheter.     

Ambulatory Electrocardiography for the Detection of Pacemaker Lead Failure

The suboptimal performance of some polyurethane bipolar pacing leads has highlighted concern about the optimal method of monitoring pacemaker lead performance. Since the manifestations of premature lead failure may be initially intermittent, we hypothesized that ambulatory electrocardiography (AECG) would be a more sensitive tool for the detection of pacing lead failure compared to increased pacemaker clinic surveillance. Since the Medtronic safety alerts on the 4012, 4082, and 4004 leads, we have followed 261 patients by serial AECG and 165 patients by increased pacemaker clinic surveillance. Lead failures were identified in 75 patients: 68 in the AECG group (31 %) and 7 in the clinic group (4%, P < 0.001). Repeat AECG confirmed the lead failure in 38 (97%) of 39 patients in which it could be done. Pacing lead failure documented by AECG could be confirmed by a subsequent clinic assessment in only 15 (25%) of 60 patients evaluated (P < 0.001). The actuarial survival of the 4012 lead was significantly lower in the AECG group compared to the clinic group (56% vs 87% survival at 8 years, P < 0.002). Similar trends were observed for the 4082 and 4004 leads. AECG is a more sensitive method of surveillance for pacemaker lead function compared to pacemaker clinic assessment. AECG should be incorporated into the routine follow-up of pacemaker patients. (PAGE 1997; 20[Pt. I]:127 4-1282)     

Effect of Concomitantly Administered Drugs on the Control of Long Term Anticoagulant Therapy

The stability of control of long term anticoagulant therapywas studied in a group of 277 patients with respect to druginteractions. Increased instability (changes of dose/month oftherapy) was related to the number of concomitant drugs takenirrespective of, and in addition to, known specific interactions.Fluctuating cardiac status in patients requiring digoxin anddiuretic therapy was a major factor in stabilizing anticoagulantcontrol.     

Pain and the administration of analgesia: what nurses say

? Pain of moderate to severe intensity continues to be an important problem for many hospitalized patients. ? Nurses spend more time with patients than any other health professional group and have a key role to play in the management of patients' pain. ? This paper reports the findings from a series of focus group interviews which were undertaken to explore nurses' perceptions regarding pain and the administration of narcotic analgesia. ? Themes identified from participants' comments related to (1) the pivotal role of nurses in pain management; (2) nursing assessment and pain management decisions (3) individual factors influencing nurses' pain management decisions and (4) the influence of others on nurses' pain management decisions. ? These findings have implications for further research and the development of innovative educational strategies.     

Edward Martin (1859–1938). The founding father of modern clinical andrology

Edward Martin (1858-1938) was the first surgeon to treat successfully the problem of obstructive azoospermia, a feat that he first described in 1902. He subsequently carried out a total of 11 such operations that resulted in seven patencies and three pregnancies. He also demonstrated that the epididymis was the major site of these obstructive lesions. He pointed out the need for semen analysis in diagnosis and also demonstrated that azoospermia could have two causes, namely spermatogenic failure and ductal obstruction. He also made some important observations on sperm movement. He was probably the first clinician to demonstrate surgically ejaculatory duct obstruction, vasal atrophy and congenital absence of the vas. Most important of all, he demonstrated the need for accurate diagnosis in the treatment of male infertility. An argument is put forward that Edward Martin deserves the title of the 'Founding Father of Modern Clinical Andrology'.     

Aural symptoms and hearing loss in patients with lupus

OBJECTIVE: Systemic lupus erythematosus causes widespread tissue injury from deposition of immune complexes. The prevalence of aural symptoms in this disease was evaluated. METHODS: The presence of tinnitus, hearing loss, and fluctuating hearing was evaluated by a self-directed questionnaire in patients aged 65 or less from a lupus clinic. Patients reporting aural symptoms were compared with those reporting none, by use of demographics and disease duration. Comparison was also made with historic serologic data. Audiometry was offered to all patients with lupus reporting aural symptoms and was completed in 10. RESULTS: Twenty-six (31%) of 84 patients with lupus reported aural symptoms. Patients reported a combination of symptoms: unilateral hearing loss with or without tinnitus in 13 (15%) of 84 and bilateral hearing loss with or without tinnitus in 14 (17%) of 84. No statistical difference was measured between symptomatic and asymptomatic patients when compared by average age, duration of disease, history of noise exposure, head trauma, and infectious ear diseases. Statistically significant differences were detected only when comparing average creatinine and C3 levels. Of those patients tested by audiometry, 7 of 10 had abnormal pure-tone thresholds. Asymmetric findings were present in 6 of these 7 patients tested. CONCLUSION: Aural symptoms are prevalent among patients with lupus. Asymmetric symptoms and hearing loss are most common. The cause may relate to immune-complex disease and/or vasculitis. (Otolaryngol Head Neck Surg 1998;118:762-5.)     

The use of Roy's adaptation model applied to a patient with breast cancer

Roy's adaptation model provides a framework for holistic oncology nursing practice. In this article an overview of Roy's model is provided, and the model is applied to a patient with breast cancer for an assessment of behaviour and the stimuli influencing behaviour, and for the planning and evaluation of nursing care. Also, a comprehensive list of nursing diagnoses is categorized according to Roy's four adaptive modes.     

Sensitivity of Entamoeba histolytica and Entamoeba dispar patient isolates to human complement

Twenty-one Entamoeba histolytica and 56 Entamoeba dispar patient isolates were investigated for their sensitivity to the classical and alternative pathway of human complement. E. histolytica and E. dispar patient isolates were differentiated by polymerase chain reaction and hexokinase isoenzyme typing. It was found that 90.3% (±12.0%) of the trophozoites of E. histolytica were lysed after 30 min by the alternative pathway of complement in the presence of 50% human serum (19 isolates showed lysis rates higher than 80%), whereas E. dispar cells were less susceptible to the alternative pathway as 68.8% (±28.2%) of lysis occurred. However, 23 of the E. dispar isolates were lysed between 100 and 80% (90.9%±9.1%), demonstrating that about half of the tested E. dispar isolates were highly sensitive to complement lysis. Only 11 of the E. dispar isolates were proven to be 'resistant' to the alternative pathway of complement and were lysed less than 40%. These results are in conflict to earlier publications, describing resistance of E. dispar to complement lysis (Hamelmann et al. 1992, 1993).