Teletherapy for subfoveal choroidal neovascularisation of age-related macular degeneration: results of follow up in a non-randomised study

AIM

A preliminary report indicated stable or improved vision in 12 of 19 patients with subfoveal choroidal neovascularisation treated with 12 or 15 Gy of 6 MV photons to the affected macula after an average follow up of 18 months. Here the prolonged follow up findings in this group of treated patients is reported which was further increased to 41.

METHODS

Forty one patients with subfoveal choroidal neovascularisation were treated with 10, 12, or 15 Gy of 6 MV photons to the macula of the affected eye. Thirteen eyes of 12 patients were also observed as a non-randomised comparison group.

RESULTS

At 12, 18, and 24 months of follow up the mean change in visual acuity in eyes treated with radiotherapy was less than 1 Bailey-Lovie line from that measured at presentation. By contrast, the eyes in the comparison group lost 3.7 lines of acuity at 12 months which increased to 4.5 at 24 months. These differences were highly significant at each of the time points. When initial visual acuity was taken into account, treated eyes lost on average 12% of baseline acuity throughout follow up, whereas eyes belonging to the untreated group lost 50% of baseline acuity at 1 year, and 75% at 2 years. There was no significant difference in visual outcome between the three dose regimens used, which may simply be a reflection of the small sample size in each group. There was no evidence of radiation induced retinopathy or optic neuropathy in any treated patients.

CONCLUSIONS

Teletherapy appeared to have a treatment effect in eyes with subfoveal choroidal neovascularisation resulting in maintained visual function without significant radiation induced morbidity.

Body surface ECG potential maps in acute myocardial infarction

An algorithm for the early detection of acute myocardial infarction (MI) using body surface electrocardiographic potential mapping has been developed. The mapping system consists of a 64-hydrogel electrode harness applied rapidly to the anterior chest, from which electrocardiographic signals are stored on a memory card and processed by computer. At each of the 64 points, QRS and ST-T isointegrals and 10 other features of the QRST segment are measured. Using these measurements, new variables are derived that express the shape of the three-dimensional geometric surface of the map. The isointegrals, features, and shape variables are used in a variety of techniques to discriminate between MI and control subjects. Maps were recorded from 69 patients at initial presentation of chest pain suggestive of acute MI and from 80 healthy control subjects. Using a multiple logistic regression technique, 14 variables were identified that correctly classified 79 of the 80 control subjects (specificity, 98.8%) and 65 of the 69 MI patients (sensitivity, 94.2%). The algorithm based on these 14 variables was applied prospectively to maps recorded on a further 48 control subjects and 59 patients with acute MI. Of the MI patients, 31 had inferior, 13 inferoposterior, 10 anterior, 2 posterior, 1 lateral, 1 inferior with right bundle branch block, and 1 anterior non Q wave MI. The algorithm correctly classified all 48 control subjects (specificity, 100%) and 57 of the 59 MI patients (sensitivity, 96.6%). Marked differences in the three-dimensional geometric map surfaces between the control subjects and MI patients were demonstrated. Variables derived from these surfaces form the basis of an algorithm with a high sensitivity and specificity for the automated detection of acute MI. The design of adaptive algorithms and their application to patients with chest pain and atypical electrocardiographic changes, particularly ST depression, may lead to the earlier detection of MI and greater numbers of patients receiving thrombolytic therapy.

Time delays to lytic therapy and outcome in 100 consecutive patients with a history suggestive of acute myocardial infarction in an area with access to a mobile coronary care unit

Time delays to fibrinolytic treatment and outcome were assessed in 100 consecutive patients, with suggestive symptoms and electrocardiographic changes of acute myocardial infarction, admitted to the coronary care unit of this hospital. All patients admitted from out-of-hospital had access to a mobile coronary care unit. Initially, 40 patients called a general practitioner, 30 called the '999' operator, 12 called the mobile coronary care unit, 10 reported directly to the Accident and Emergency Department, seven were in-hospital and one spoke to the general practitioner's receptionist. Subsequently, 59 patients were attended by the mobile coronary care unit, 34 were admitted via the Accident and Emergency Department and seven had symptoms in-hospital. Thrombolytic therapy was initiated in 45/59 (76%) patients by the mobile coronary care unit staff and in 29/34 (85%) patients in the Accident and Emergency Department by cardiac staff. The remaining 26 patients received thrombolytic treatment in the hospital coronary care unit or cardiac department. The mean (+/- SEM) time from symptom onset to the initiation of thrombolytic therapy was 127 (+/- 11 min) for those patients treated by the mobile coronary care unit staff and for those treated in the Accident and Emergency Department was 187 (+/- 13 min) (P = 0.005). Multiple regression analysis showed significant reductions in total time delay if patients received thrombolytic therapy by the mobile coronary care unit staff out-of-hospital, when chest pain began in-hospital, or if patients had a previous myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Portable cardiac mapping assessment of acute ischaemic injury

A portable cardiac mapping system is used to improve the accuracy of diagnosis of acute ischaemic injury outside hospital. Patients presenting chest pain suggestive of myocardial infarction (MI) were mapped by attendant medical personnel operating from a mobile coronary unit. These first MI maps were compared against average normal maps using QRS and ST-T isointegral values. Discriminant function analysis performed on the parameters achieved a sensitivity of 90% and a specificity of 96%.

Discriminant function analysis of body surface potential maps in acute myocardial infarction

Using a newly developed 64-electrode portable mapping device, QRS and ST-T isointegral maps were compared in 194 control subjects and 101 patients. One hundred ninety-four control subjects (mean age, 48 years; 120 men) with no history of cardiac disease were selected randomly and mapped. One hundred one patients (mean age, 62 years; 77 men) were mapped at presentation of chest pain suggestive of first myocardial infarction (MI); all patients had classic 12-lead electrocardiographic findings--46 with anterior and 55 with inferior MI. The diagnosis was confirmed in all cases by a significant rise in serial cardiac enzymes. The mean delay between onset of chest pain to map recording was 163 minutes. Of the 101 patients, 78 were first mapped outside the hospital. Applying discriminant function analysis to the isointegral measurements made on the control subjects and on the first map of MI patients achieved a correct classification of 97% of the control subjects (189 of 194) and 72% of the anterior (33 of 46) and 76% of the inferior (42 of 55) MI groups. This preliminary study suggests that discriminant function analysis, based on isointegral maps, not only provides a method of separating control subjects from MI patients but that it can also differentiate between types of infarct. Further studies are required to improve the predictive values of discriminant function and to extend the methodology to assess both the site and size of MI.

The incidence of child sexual abuse in Northern Ireland

This is part of a major epidemiological survey of the reported incidence (new cases) of child sexual abuse in Northern Ireland. Based on multi-source methodology, the study used computer-based record linkage techniques to find the number of incident cases occurring in the Province in 1987. Reporters involved with the incident cases were interviewed by OEV who recorded details of the child, the abuse, and the abuser using a specially designed questionnaire. Age-sex specific incidence rates adjusted for potential misclassification were computed and allowance made for under-ascertainment. Overall, 408 Established cases were reported during 1987. The corresponding incidence rate for Northern Ireland was 0.9 cases per 1000 children. When Suspected and Alleged cases were compared with Established cases, a further 119 cases were allocated by discriminant function analysis to the Established group, and the rate rose to 1.16 per thousand. Selected reporters were interviewed about ascertainment which was estimated to lie between 62% and 74%. If the lowest level of ascertainment applied the corresponding incidence rate for Northern Ireland would increase to 1.87. These figures are higher than those currently reported elsewhere in the UK, but methodological differences in study design hamper interregional comparisons. A number of relevant methodological problems are discussed.

Long-term survival after resuscitation from ventricular fibrillation occurring before hospital admission

Factors related to long-term (post-discharge) outcome following successful resuscitation from pre-hospital ventricular fibrillation by a physician-manned mobile coronary care unit were studied. Between 1 January 1966 and 31 December 1987, 190 patients were resuscitated from pre-hospital ventricular fibrillation (158 male; mean age 56 years). The aetiology of ventricular fibrillation was acute myocardial infarction in 131 patients (69 per cent), ischaemic heart disease without infarction in 48 (25 per cent) and other or unknown in 11 (6 per cent). Predicted actuarial survival rates at 1, 2, 5, 10 and 20 years were 76 per cent, 66 per cent, 41 per cent, 27 per cent and 12 per cent respectively. Of 128 recorded deaths over 20 years, 85 per cent were cardiac and 48 per cent were defined as sudden death outside hospital. Factors significantly associated with increased long-term mortality (p less than 0.05), based on analysis of 10 year actuarial life tables using the Lee-Desu statistic were ventricular fibrillation due to ischaemic heart disease without infarction rather than acute myocardial infarction, a history of previous myocardial infarction, a history of hypertension, digoxin and diuretic therapy before ventricular fibrillation and digoxin as discharge medication, and failure to stop smoking after discharge from hospital by patients who had been smoking prior to ventricular fibrillation. In addition, Cox's regression analysis showed that patient age greater than or equal to 60 years was significantly associated with increased long-term mortality. On multivariate analysis, factors independently associated with increased long-term mortality were ventricular fibrillation occurring before 1977, previous myocardial infarction or hypertension and digoxin as discharge medication.(ABSTRACT TRUNCATED AT 250 WORDS)

Thallium scintigraphy in patients with angina at rest

Sixty six patients with angina at rest were investigated by exercise electrocardiography, thallium scintigraphy, and coronary arteriography. A positive exercise electrocardiogram was highly predictive (93%) but poorly sensitive (52%) of coronary artery disease (greater than or equal to 50% stenosis). Thallium scintigraphy was as predictive of the presence of coronary artery disease (91%) but was also highly sensitive (91%). The diagnostic contribution of the thallium scan was greatest in those patients with an inconclusive exercise electrocardiogram without Q waves.

Effect of nifedipine on arrhythmias in the acute phase of myocardial infarction

In a double-blind placebo-controlled trial to study the effect of nifedipine on ventricular arrhythmias among patients with acute myocardial infarction, 434 patients with suspected myocardial infarction were randomized within 6 h from the onset of chest pain to treatment with nifedipine (p = 217) or placebo (p = 217). During the 48-h treatment period, a 10-mg capsule containing active drug or placebo was administered sublingually every 4 h for 24 h, then orally every 4 h for the next 24 h. Acute myocardial infarction was confirmed in 295 patients (146 in the nifedipine group and 149 in the placebo group). Twenty-four hour ECG tape analysis during 1-5 h from onset of chest pain showed that there was no significant difference in the number of patients with ventricular ectopics, ventricular couplets, ventricular tachycardia (3-9 beats), self terminating or sustained ventricular tachycardia between the two treatment groups. Also during the greater than 5-24 h from onset of chest pain, the numbers of patients with ventricular ectopics, multifocal, bigeminal or couplets, self-terminating ventricular tachycardia or sustained ventricular tachycardia did not differ significantly. However, there was a significant reduction in the number of patients with short runs of ventricular tachycardia (3-9 beats) in the nifedipine-treated group. There was no significant difference among patients with ventricular fibrillation between the two treatment groups.

Fatal ischaemic heart disease in Belfast: a comparison of two community surveys

Data from two community surveys in Belfast were used to compare all deaths attributed to ischaemic heart disease during two one-year periods (1965/66 and 1981/82). There was an increase in mortality in men of all ages from 3.3 to 4.4 per 1,000 population (33%) and in women from 1.6 to 3.1 per 1,000 population (94%). Only in men aged less than 70 years was the mortality rate unchanged (2.2 per 1,000 population). The proportion of deaths in persons whose fatal attack began outside the hospital was virtually unchanged (65% in 1965/66 compared with 69% in 1981/82). Survival time was markedly decreased in the later survey, as were delay times in initiating medical care. The increase in mortality probably is due to an increase in the incidence of acute myocardial infarction. The introduction of mobile coronary care in Belfast in 1965 seems to have had equal effects in reducing mortality inside and outside hospital.

Effect of nifedipine on enzymatically estimated infarct size in the early phase of acute myocardial infarction

In a double blind placebo controlled trial, 434 patients with suspected myocardial infarction were randomised to treatment with nifedipine (n = 217) or placebo (n = 217) within six hours from the onset of chest pain. During the treatment period of 48 hours, a 10 mg capsule containing nifedipine or placebo was given sublingually every four hours for 24 hours, then orally every four hours for the next 24 hours. Acute myocardial infarction was confirmed in 295 patients (146 in the nifedipine group and 149 in the placebo group). The median delay time to intervention with nifedipine in patients with acute myocardial infarction was 111 minutes. Infarct size was assessed by the estimation of release of creatine kinase isoenzyme MB and creatine kinase from blood samples taken every four hours for 48 hours. The total mean (SEM) creatine kinase MB released was 406.4 (27.2) IU/l in the nifedipine group and 345.7 (20.5) IU/l in the placebo group. Total mean (SEM) creatine kinase released was 2749.6 (165.1) IU/l in the nifedipine group and 2698.4 (145.9) IU/l in the placebo group. In hospital mortality was similar for both the nifedipine and placebo groups (6.6% and 5.8% respectively). Treatment with nifedipine in the early phase of acute myocardial infarction seems to have no effect on enzymatically measured infarct size.