Surgery for control of recurrent life-threatening ventricular tachyarrhythmias within 2 months of myocardial infarction.

Twenty-seven patients (mean age 57 +/- 7 years) underwent surgery for control of recurrent drug-refractory ventricular tachyarrhythmias (uniform ventricular tachycardia alone in 9 patients, ventricular tachycardia and ventricular fibrillation in 15 and ventricular fibrillation alone in 3) within 2 months of acute myocardial infarction. The mean number of major arrhythmic episodes per patient was 15 (range 2 to 200) and of drug failures 4 +/- 2. Left ventricular function was severely impaired in the majority (ejection fraction 29%; range 14% to 47%) and 18 patients (66%) had a left ventricular aneurysm. Endocardial resection guided by a combination of endocardial activation mapping during tachycardia and fragmentation mapping during sinus rhythm was performed in all patients. All electrically abnormal left ventricular endocardium was excised. Eight patients (29.6%) died within 30 days of surgery. Death was not related to age, time of surgery after infarction, ventricular function, bypass time or type of arrhythmia. Patients requiring emergency surgery had a higher early postoperative mortality rate than did those undergoing planned surgery (43% versus 15%). During a follow-up period of 32 +/- 20 months, there have been no arrhythmic deaths and only three patients (16%) have required antiarrhythmic drug therapy. When required in the early weeks after infarction, surgery for ventricular arrhythmias offers a high cure rate at a risk related to the patient's preoperative arrhythmia frequency, which in turn relates to the risk of arrhythmic death.

Internal resection of posterior uveal melanomas.

AIMS: To evaluate the safety and efficacy of internal resection in the treatment of malignant melanoma of the choroid. METHODS: 32 consecutive patients with histopathologically proved malignant choroidal melanomas were treated with internal resection. 29 of the 32 (90.6%) tumours were within 2 disc diameters of the optic nerve or fovea. The surgery was performed at two university centres by one of the authors. Follow up was between 1 and 85 months (mean 40.1 months). RESULTS: Three patients developed distant metastases and died of malignant melanoma (metastatic and mortality rate 9.4%). In one case, distant metastases developed in association with an intraocular recurrence. There have been no other intraocular recurrences. The most common postoperative complication was vitreous haemorrhage, which occurred in 12 patients (37.5%); cataract occurred in eight eyes; and three patients developed retinal detachment postoperatively. Three of the operated eyes have been enucleated (9.4%); a total of four (12.5%) have lost light perception. 10 patients (31.2%) had visual acuities of 6/60 or better and 18 of 32 (56.3%) were between 6/120 and light perception. CONCLUSION: These data suggest that the internal resection of posterior uveal melanomas is a reasonable globe saving management option. This treatment modality is particularly well suited to elevated tumours in close proximity to the optic nerve or fovea.

Management of submacular hemorrhage with intravitreal sulfur hexafluoride: a pilot study.

BACKGROUND: Some success has been reported with the intravitreal use of tissue plasminogen activator (tPA) and perfluoropropane gas in the management of large submacular hemorrhages. However, the dosage of tPA that has been used (100 micrograms) has a narrow margin of safety, and it remains to be shown that intravitreal tPA can cross the retina and effect subretinal clot lysis. We carried out a pilot study to evaluate the efficacy of intravitreally administered sulfur hexafluoride (SF6) gas alone in the management of large submacular hemorrhages secondary to age-related macular degeneration (AMD). METHODS: Three patients with large submacular hemorrhages secondary to AMD seen at a university-affiliated teaching hospital in Ottawa were treated with an intravitreal injection of 0.6 mL of SF6 gas. They were instructed to assume a prone position for 7 to 10 days. The patients were followed 3, 7, 14 and 28 days after the procedure and monthly thereafter for at least 6 months. Colour photography and fluorescein and indocyanine green angiography were performed immediately before and 2 weeks after the procedure and, thereafter, at the discretion of the treating ophthalmologist. RESULTS: In all three cases significant inferior displacement of the submacular blood was observed. Two patients showed an improvement of vision from counting fingers to 20/70 and to 20/200. In one case the submacular blood was displaced such that laser photocoagulation of a juxtafoveal choroidal neovascular membrane became possible. INTERPRETATION: The results suggest that intravitreally administered SF6 alone may have a role in the management of selected cases of neovascular AMD complicated by significant submacular hemorrhage. These results call into question the utility of adjunctive intravitreal tPA in such cases.

Toxicity of intravitreal interferon alpha-2b in the rabbit.

OBJECTIVE: To investigate the toxicity of single doses of intravitreally administered interferon alpha-2b in the New Zealand white albino rabbit. INTERVENTIONS: One eye each of six rabbits received an intravitreal injection of 1000, 10,000, 100,000, 500,000, 1 million or 2 million units of interferon alpha-2b reconstituted in 0.1 mL of balanced salt solution. The fellow eye of the first three rabbits received an intravitreal injection of the same volume of balanced salt solution. OUTCOME MEASURES: Media opacities, toxic effects to the retina, optic nerve or other ocular structures. RESULTS: The injection of 2 million units of interferon alpha-2b elicited an immediate dense vitreous haze that largely cleared within 24 hours as well as numerous intraretinal hemorrhages that were no longer visible 7 days after injection. Histopathological study of this eye 14 days after injection showed a diffuse mixed inflammatory cell infiltrate with retinal vacuolation and ganglion cell dropout. In the remaining eyes, to dosages of 1 million units, the agent produced no clinically or pathologically evident toxic ocular effects. CONCLUSIONS: Interferon alpha-2b appears to be safe and well tolerated up to dosages of 1 million units.

Use of a macular buckle in the treatment of exudative age-related macular degeneration.

BACKGROUND AND OBJECTIVE: To evaluate a macular buckle for exudative choroidal neovascularization secondary to age-related macular degeneration (ARMD). PATIENTS AND METHODS: Forty-two eyes with choroidal neovascular membranes (CNVM) secondary to ARMD underwent surgical placement of a macular buckle. A Gore-Tex strip (2.0-2.5 mm wide) was button-holed through a 5 mm diameter silicone sponge (9 mm long) and placed behind the macula underneath the CNVM by the same surgeon (Dr Peyman) in all cases. Follow-up ranged from 7-76 months (mean, 20.9 months). RESULTS: Of 12 eyes with classic subfoveal CNVM: 4 (33%) gained 2 or more lines of Snellen visual acuity; 3 (25%) gained 1 line, remained the same, or lost 1 line; and 5 (42%) lost 2 or more lines (range + 6 to - 6 lines). Of 22 eyes with ill-defined subfoveal CNVM: 12 (54%) gained 1 line, remained the same, or lost 1 line; and 10 (46%) lost 2 or more lines (range + 1 to - 8 lines). Eight eyes with ill-defined juxtafoveal CNVM had the following visual acuity outcomes: 5 eyes (62%) maintained the same level of Snellen visual acuity (gained 1, 0, or lost 1 line); and 3 (38%) got worse (lost 2 or more lines of Snellen visual acuity, range + 1 to - 6 lines). Ten eyes (24%) bled subretinally during the follow-up period (average 11.5 months, range 14 days to 27 months), all outside the area of indentation of the macular buckle. CONCLUSIONS: The macular buckle treatment for exudative subretinal choroidal neovascular membranes in ARMD stabilized visual decline and displaced significant subfoveal hemorrhage.

Radiofrequency catheter ablation. A new, curative therapy for supraventricular tachyarrhythmias.

Radiofrequency catheter ablation is a major advance in the treatment of tachyarrhythmias, particularly SVT. It offers the chance of permanent cure, without the need for major surgery, for a condition that is usually life-long and necessitates years of drug treatment. At present the risks of RF ablation are low, although not insignificant; potential subjects must be given the opportunity of making an informed choice. With improvements in technique and equipment, the indications for this procedure are likely to widen.

Permanent cardiac pacemakers. Indications and current trends.

In Australia, most patients requiring permanent cardiac pacing have either high grade atrioventricular block or sick sinus syndrome. Many receive simple ventricular demand pacemakers, but more 'physiological' systems are now available that allow changes in pacing rate depending on metabolic needs. The indications for pacemakers and the types available are discussed in this article.

Management of dry retinal folds.

BACKGROUND: To describe the surgical technique used in the management of two cases of dry retinal folds which occurred following retinal detachment surgery. METHODS: Two patients with persistent dry retinal folds. RESULTS: Patients underwent complete vitrectomy and membrane peeling, followed by injection of perfluorocarbon liquid. The retina was prodded and massaged flat with a silicone-tipped cannula under the perfluorocarbon liquid. The folds disappeared and the retina remained flat. CONCLUSION: The use of gentle manipulation under heavy perfluorocarbon liquids is an effective strategy for managing longstanding dry posterior retinal folds.

Primary cardiac amyloidosis in a young man presenting with angina pectoris.

A 32 year old man presenting with typical angina pectoris was found to have primary cardiac amyloidosis. Myocardial infiltration was strongly suggested by echocardiography, and a histological diagnosis was confirmed by renal biopsy. Nevertheless, technetium pyrophosphate myocardial scanning, recently proposed as a sensitive non-invasive test, showed negative results despite widespread cardiac involvement confirmed at necropsy after unexpected sudden death. Postmortem findings also showed subintimal amyloid material in a severely narrowed right coronary artery. This case highlights several unusual clinical features in a patient with advanced primary cardiac amyloidosis.

Cost effectiveness of radiofrequency catheter ablation in the treatment of symptomatic supraventricular tachyarrhythmias.

BACKGROUND: The recent advent of radiofrequency (RF) catheter ablation as a curative therapy for supraventricular tachyarrhythmias has challenged the role of long term drug treatment, which is essentially a palliative therapy. To date, however, no data have been published on the cost-effectiveness of RF ablation as compared with drug treatment in the Australian setting. AIMS: The study aimed to compare actual and projected costs of these two treatment options in a consecutive group of patients having RF ablation as treatment for symptomatic tachyarrhythmias. METHODS: The cost effectiveness of RF catheter ablation was assessed in 26 patients having RF ablation, using a hypothetical model of continued drug therapy in the same group of patients. A 'cost saving' criterion was used for cost effectiveness. Actual costs for the RF ablation and for continued drug therapy were based on data from medical records and from the answers to a detailed patient questionnaire. Analysis included costs of prior diagnostic electrophysiology (EP) study (17/26 patients), general anaesthesia (GA: 20/26 patients), post-ablation echocardiography (10/26 patients), and late follow-up EP study (7/26 patients). The in-hospital stay for the RF ablation was two days in all cases, and no patient required implantation of a permanent pacemaker. The RF ablation procedure was successful in 23/26 patients (88.5%) with late recurrence of tachycardia in one patient. After a median follow-up of nine months, 22/26 patients no longer require antiarrhythmic drug therapy. RESULTS: The mean per patient cost of RF ablation was $4067 in the study group. This reduces to $2546 if prior EP study and GA are excluded. The mean per patient cost of continued medical therapy was $700 per year. Extrapolating over 20 years and allowing for an annual 5% inflation factor, RF ablation becomes cost saving in 5.5 years (3.8 years if prior EP and GA are excluded). Over 20 years, continued drug therapy would be four to five times more expensive than RF ablation in the patient study group. We consider RF ablation to be a cost-effective alternative to long term drug therapy in patients with supraventricular tachyarrhythmias.

Delayed ventricular depolarization--correlation with ventricular activation and relevance to ventricular fibrillation in acute myocardial infarction.

Signal averaging to detect abnormalities in the terminal phase of ventricular depolarization has been performed in several groups of patients with various manifestations of ischaemic heart disease. Late potentials were common in patients with VT and in a group of patients having cardiac surgery. Findings in the surgical group highlighted the close correlation of late potentials with delayed, fragmented epicardial activation supporting the hypothesis that late potentials reflect a myocardial substrate which would support re-entrant VT. The findings in the surgical group allowed a definition of late potentials which could be applied to other patients in the study, and also demonstrated a spectrum of late depolarization abnormalities. Signal averaging is technically feasible in the noisy CCU environment but late potentials were detected in few patients early in AMI. Late potentials were also rarely seen in patients with VF and therefore cannot be construed as a predictive index of this arrhythmia.

Influence of left ventricular function on signal averaged late potentials in patients with coronary artery disease with and without ventricular tachycardia.

Left ventricular dysfunction has been suggested as a cause of late potentials on the signal averaged ECG of patients with coronary artery disease. We compared the averaged surface ECG with angiographic findings in 57 patients with coronary artery disease and left ventricular dysfunction. Sixteen patients had sustained ventricular tachycardia and 41 had no documented arrhythmia. These two patient groups were comparable with respect to age, mean ejection fraction, and wall motion score. Late potentials, defined as voltage less than 25 microV in the last 40 msec of the filtered QRS complex, were found in 10 of 16 patients with ventricular tachycardia and in 6 of 41 patients without arrhythmia (p less than 0.005). However, late potentials were independent of ejection fraction, wall motion score, or presence of dyskinesis in both groups. There was no correlation between the total filtered QRS duration and ejection fraction or wall motion score in either patient group. In patients with coronary artery disease, late potentials are associated with ventricular tachycardia but are independent of global or regional left ventricular function. This finding has important implications for studies of the prognostic value of late potentials following myocardial infarction.

The management of giant retinal tears using perfluoroperhydrophenanthrene. A multicenter case series. Vitreon Collaborative Study Group.

OBJECTIVE: The purpose of the study was to determine the predictors of success and evaluate the use of perfluoroperhydrophenanthrene as an intraoperative and postoperative tool in the management of giant retinal tears in a multicentered collaborative study. DESIGN: Multicentered prospective case series. PARTICIPANTS: Twenty-three centers consecutively enrolled 162 eyes of 161 patients with retinal tears 90 degrees or greater in circumferential extent. INTERVENTION: Perfluoroperhydrophenanthrene was used as an intraoperative surgical adjunct in all cases and left after surgery in 16 eyes (9.9%). MAIN OUTCOME MEASURES: Retinal reattachment and visual acuity. RESULTS: Intraoperative reattachment was achieved in 158 eyes (97.5%); 147 eyes (90.7%) remained attached at their most recent follow-up. Seventy-nine eyes (48.8%) experienced an improvement in their visual acuity, 26 eyes (16.0%) remained unchanged, and 57 (35.2%) worsened. Recurrent retinal detachment occurred in 80 patients (49.4%). Other significant postoperative complications included cataract formation in 20 (39.2%) of 51 eyes, macular pucker in 12 (7.4%), corneal decompensation in 10 (6.2%), and hypotony (intraocular pressure equal to or less than 5 mmHg) in 9 (5.6%). A chi-square analysis of preoperative characteristics showed that hypotony (P = 0.007), macular detachment (P = 0.020), a history of cataract extraction (P = 0.003), poor visual acuity (P = 0.000), giant tear extent greater than 180 degrees (P = 0.004), and higher grade proliferative vitreoretinopathy (P = 0.000) all predicted a poor visual outcome. Vitreon (Vitrophage, Inc., Lyons, IL) was left in 16 eyes (9.9%) for an extended postoperative retinal tamponade for between 3 and 1034 days (mean, 87.2 days). The Vitreon was well tolerated, and these eyes experienced a similar outcome and rate of retinal reattachment to the rest of the group. CONCLUSIONS: Vitreon is a safe and useful adjunct to pars plana vitrectomy in the management of giant retinal tears and may, additionally, be the perfluorocarbon liquid that can be used most safely as a temporary postoperative tool for extended retinal tamponade, reinforcing its role as a useful adjunct in the management of these complex retinal detachments.