Large Tip Electrodes for Successful Elimination of Atrial Flutter Resistant to Conventional Catheter Ablation

The most widely accepted criterion for successful radiofrequency catheter (RFC) ablation of typical atrial flutter is the development of bi-directional isthmus block. In a subset of patients, conventional RFC ablation fails to achieve this endpoint because deeper and wider lesions are required. We investigated the efficacy of a long 8-mm tip catheter in these cases.One hundred and seventy-four consecutive patients (137 male; 61 ± 9 years) with recurrent typical atrial flutter underwent conventional RFC ablation first with a standard 4 mm tip catheter. In resistant cases (n = 52), ablation was continued using a large tip 8-mm catheter when the 4-mm tip catheter failed. Resistant atrial flutter was identified when 21 RFC pulses failed to reach the selected endpoint of bi-directional isthmus block or in cases of transient bi- directional block (at least 3 episodes).In 122 of the 174 patients (70%) conventional atrial flutter ablation was successfully performed with 13 ± 5 RFC applications. In the remaining 52 subjects (30%), the ablation procedure was completed using the large tip electrode catheter. In 30 of these 52 patients (58%), the catheter was changed because of persistent intra-atrial conduction after 21 RFC pulses and in 22 (42%) because of intermittent conduction block after 11 ± 5 applications. Using the large tip electrode catheter, the selected endpoint was achieved in all patients of both groups with 3 ± 2 RFC pulses (power output of 50–60 W, pulse duration of 60 sec). No post-procedure complications were observed. After 15 ± 5 months of follow-up, 16 patients (9%) had recurrence of atrial flutter. Five of the patients had been in the resistant group. In patients with atrial flutter resistant to conventional ablation therapy, the long tip (8-mm) catheter appears to be a safe and effective alternative to use of the conventional 4-mm tip catheter.     

Diagnosis and localization of laceration of the thoracic duct: usefulness of lymphangiography and CT

The usefulness of lymphangiography and CT in the diagnosis and localization of laceration of the thoracic duct was evaluated in 12 patients with chylothorax or chylous ascites after surgery. Bipedal lymphangiography was performed in all 12 patients. The last four patients studied also had CT after lymphangiography. Seven patients had abnormal findings on lymphangiograms; five with leaks from the thoracic duct, one with a lymphocele in a nephrectomy bed, and one with obstructed intestinal lymphatic vessels after thoracotomy. Five patients had no evidence of lymphatic leakage. CT in one patient with evidence of a leak on lymphangiography showed extravasation of contrast medium into the mediastinum and pleural space. CT in three patients with no abnormalities on lymphangiography also showed no abnormalities. Four of the five thoracic duct lacerations and the lymphocele were confirmed surgically. The diagnosis of obstructed intestinal lymphatic vessels was supported clinically. Four of the five patients with normal findings on lymphangiograms had resolution of their pleural effusions and no evidence of recurrence during a follow-up period of 1-27 months. One patient with normal findings on lymphangiography had an alternative diagnosis established at surgery. Laceration of the thoracic duct was accurately diagnosed and localized with lymphangiography, which allowed definitive surgical repair. CT was of little additional value in diagnosing these injuries.     

Modulation of rat pituitary growth hormone by 670 nm light

In rat pituitary somatotrophs, cytochrome oxidase is co-packaged with growth hormone (GH) in some storage granules. Because this enzyme is thought to be the molecular photoacceptor of red-near infrared light, and because exposure of diverse tissue systems to 670 nm visible light affects their biological responses (e.g., wound healing), we tested the idea that exposure of rat pituitary cells, rat hemi-pituitary glands and rat pituitary homogenates to 670 nm light in vitro might alter GH storage and/or release. In this report we offer evidence to show that light treatment (670 nm, 80 s, intensity 50 mW/cm², energy density 4 J/cm²) up-regulates GH release, in part by breakdown of intracellular, oligomeric GH as determined by gel filtration chromatography.     

The behavioral pharmacology of olanzapine, a novel "atypical" antipsychotic agent.

Olanzapine (LY170053, 2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno[2,3-b][1,5] benzodiazepine) is a novel "atypical" antipsychotic agent with 5-hydroxytryptamine2.dopamine D1/D2 antagonist activity and anticholinergic properties. In behavioral studies, olanzapine (1.25-10 mg/kg, p.o.) antagonizes apomorphine-induced climbing behavior in mice, demonstrating that the compound possesses D1/D2 antagonist activity in vivo. Olanzapine (0.3-20 mg/kg, p.o.) antagonizes 5-hydroxytryptophan-induced head twitches in mice at doses much lower than those required to block the climbing response, confirming that in vivo, the compound is a more potent 5-hydroxytryptamine2 antagonist than dopamine antagonist. Olanzapine (2.5-10 mg/kg, p.o.) also antagonized oxotremorine-induced tremor in mice. In a conditioned avoidance paradigm in rats, olanzapine inhibits the avoidance response with an ED50 of 4.7 mg/kg p.o; however, unlike other antipsychotic agents, catalepsy is only observed at much higher doses (ED50 39.4 mg/kg, p.o.). These data would suggest that the compound will be less likely to produce undesirable extrapyramidal symptoms. Unlike "typical" antipsychotics, olanzapine (1.25-5 mg/kg p.o.) increases responding during the conflict component of a modified Geller Seifter test, demonstrating that the compound may also possess anxiolytic activity. In another series of experiments, olanzapine (1.25 mg/kg, i.p.) produced clozapine-appropriate responding in a drug discrimination model in which animals had been trained to discriminate clozapine (5 mg/kg, i.p.) from vehicle. On the basis of these results, it would therefore be predicted that olanzapine will have an atypical profile and will be less likely to induce undesirable extrapyramidal symptoms than currently available drugs.     

Recurrent pulmonary embolism after Greenfield filter placement

Three patients with documented recurrent pulmonary embolism with an inferior vena cava (IVC) Greenfield filter in place were examined with contrast-material-enhanced cavography. Mechanisms for recurrent pulmonary embolism were found to be propagation of thrombus through the filter struts, occlusion of the IVC at the level of the filter, and loss of contact of the filter hooks with a portion of the caval wall.     

A prospective analysis of the accuracy and cost-effectiveness of digital subtraction angiography for living-related renal donor evaluation

From 1982 to 1984, we conducted a prospective study to evaluate the usefulness of i.v. renal digital subtraction angiography (DSA) for living-related donor (LRD) evaluation. Twenty-eight LRDs were evaluated with the traditional approach of intravenous pyelography (IVP) and standard catheter arteriography (SCA) (group 1). During the same period, 33 LRDs underwent renal DSA and IVP from a single i.v. contrast injection (group 2). If renal arterial imaging with DSA was considered satisfactory, no further radiographic studies were done (group 2-A, n = 23). If renal arterial imaging with DSA was not satisfactory, SCA was then obtained (group 2-B, n = 10). DSA alone accurately defined the number and location of renal arteries in 21 of 23 patients from group 2-A, and in 5 of 10 patients from group 2-B. The major limitation of DSA was in patients with multiple renal arteries; accurate imaging was obtained in only 7 of these 13 patients (54%). In group 2 overall, preoperative renal imaging was not accurate in 2 of 33 patients (6%); in both cases, an unsuspected polar artery was found at nephrectomy. The mean cost per patient of all radiographic renal imaging studies was $953.00 for group 2 and $1721.00 for group 1. These data suggest that the approach of preferentially evaluating LRDs with DSA-IVP, and obtaining SCA only if DSA yields poor visualization, is more cost-effective but not as accurate as the traditional policy of obtaining SCA and IVP in all cases.     

Intra-arterial chemotherapy as an adjuvant to surgery in transitional cell carcinoma of the bladder

Regional chemotherapy with intra-arterial cis-platinum and doxorubicin as an adjuvant to total cystectomy and urinary diversion has been evaluated in a phase I to II study. In the first 17 patients chemotherapy consisted of 40 to 75 mg. per m. cis-platinum intra-arterially during 30 minutes, 30 to 40 mg. per m. doxorubicin intra-arterially during 60 minutes (11 patients) or 12 hours (6 patients) and 400 to 500 mg. per m. cyclophosphamide intravenously. The remaining 8 patients received 70 to 100 mg. per m. cis-platinum intra-arterially during 30 minutes. Intra-arterial chemotherapy was administered through a percutaneous catheter placed in the hypogastric artery before each course. Courses were repeated at 4-week intervals. A total of 25 patients received 58 courses (median 2 per patient). Clinical stages of disease in the patients entering the protocol were T3aNxMo (8), T3bNx-2Mo (12) and T4a-bNxMx-1 (5). Clinical response was assessed in 24 of 25 patients: 6 achieved a complete clinical response, 12 had a partial response and 7 had no response. Of 25 patients 16 underwent total cystectomy and urinary diversion with pathological staging as follows: ToNoMo in 3, T1NoMo in 1, T3aNoMo in 5, T3bNo-2Mo in 6 and T4NoMo in 1. Intra-arterial chemotherapy can produce a complete pathological response in patients with locally advanced bladder cancer and is tolerated well by most patients.