Measuring vision with temporally modulated stripes in infants and children with ROP.

PURPOSE: To determine differences in preferential looking (PL) acuities using stationary and temporally modulated stripe patterns in patients with various stages of retinopathy of prematurity (ROP). METHODS: We measured the PL acuities of 134 patients (ages 4 mo to 13 yr) with various stages of ROP. Patients were divided into six subgroups according to PL vision measured with stationary stripes: (1) equal to or better than 20/200 (n = 24); (2) worse than 20/200 to 20/400 (n = 10); (3) worse than 20/400 to 20/800 (n = 15); (4) worse than 20/800 to 20/1600 (n = 13); (5) worse than 20/1600 to 20/6400 (n = 26); and (6) worse than 20/6400 (n = 46; no stationary vision). RESULTS: In the group with PL acuity equal to or better than 20/200, no difference in vision was apparent between the two methods. In patients with acuities worse than 20/200 to 20/400, the temporally modulated PL acuities were 0.23 octave better than the PL acuities measured with the stationary stripes. The difference increased to 0.86 and 1.12 octaves in the groups with visual acuities worse than 20/400 to 20/800 and worse than 20/800 to 20/1600, respectively. The difference in the group with PL acuities worse than 20/1600 to 20/6400 was 1.69 octaves. The 46 patients with no stationary vision detected only the temporally modulated stripes. CONCLUSIONS: The results suggest that the PL acuity difference between the temporally modulated and stationary stripes increases with visual impairment. Measuring PL acuity with temporally modulated stripes is an important addition to the evaluation of severely visually impaired subjects.

Left atrial abnormality in acute myocardial infarction.

This study assessed left atrial abnormality by electrocardiogram as a predictor of left ventricular dysfunction during acute myocardial infarction. Hemodynamic, angiocardiographic, echocardiographic, and serial creatine kinase-MB studies revealed the electrocardiogram to be a significant predictor of location of acute myocardial infarction, prevalence of occlusive disease in coronary vessels, myocardial contractility, low ejection fraction, increased left ventricular end-diastolic pressure, and serial creatine kinase-MB.

Usefulness of left atrial abnormality for predicting left ventricular hypertrophy in the presence of left bundle branch block.

The objective of this study was to identify left atrial (LA) abnormality on the electrocardiogram and other related variables as predictors of left ventricular (LV) hypertrophy in the presence of left bundle branch block (LBBB). In the presence of complete LBBB, the diagnosis of electrocardiographic abnormalities is problematic and that of LV hypertrophy remains difficult. The usual electrocardiographic criteria applied for the diagnosis of LV hypertrophy may not be reliable in the presence of LBBB. Therefore, noninvasive criteria will help physicians diagnose LV hypertrophy with electrocardiography. LA abnormality on the electrocardiogram was assessed by 2 independent observers as predictor of LV hypertrophy in the presence of LBBB in 120 patients, and data were compared with those of 100 patients without LA abnormality. LV mass was calculated from echocardiographic data. Besides LA abnormality, the other variables studied for prediction of LV hypertrophy were gender, age, body surface area, body mass index, frontal axis, and QrS duration. Of the 6 criteria analyzed, the P terminal force was found to be the most common and consistent criterion to detect LA abnormality. LV hypertrophy was confirmed by echocardiographic determination of LV mass in both groups. Observers reliably differentiated between the hypertrophied and normal-sized left ventricle in the presence of LBBB by correlating LA abnormality with LV mass determined by echocardiography. Observer 1 detected LA abnormality in 89% and observer 2 in 84% of patients. False-positive results were present in 11% and 16%. The observer's recognition of LA abnormality in the present study was 91%. The 2 observers showed a sensitivity of 81% and 79% and a specificity of 91% and 88%, respectively, when diagnosis of LV hypertrophy was determined. LV mass increased significantly and was diagnostic of LV hypertrophy in 92% of patients with LA abnormality. In the remaining 11 patients (8%), the LA abnormality was of marginal abnormal magnitude. Each 0.01-mV/s increase in LA abnormality gave an increase of 30 g of LV mass. LV mass was increased in 86% of patients when corrected by body surface area. LV hypertrophy in the presence of LBBB on electrocardiography was found in only 13 patients (10%) when the 6 frequently used conventional criteria for diagnosis of LV hypertrophy by electrocardiography were used. Regression analysis revealed LA abnormality to be a strong independent predictor of increased LV mass. Multivariate analysis also revealed age, body mass index, body surface area, frontal axis, and QrS duration to be significant predictors of LV mass. This noninvasive study correlates LA abnormality by electrocardiogram and LV hypertrophy with echocardiography to conclude that LA abnormality was significantly diagnostic of LV hypertrophy in the presence of LBBB. Age, body mass index, body surface area, frontal axis, and QrS duration were also significant predictors of LV mass.

Vision in stage 5 retinopathy of prematurity after retinal reattachment by open-sky vitrectomy.

Performing vitrectomy in stage 5 retinopathy of prematurity is controversial, partially due to limited anatomical and poor reported visual results. Fifty-five eyes of 50 patients whose retinas were reattached by open-sky vitrectomy in stage 5 retinopathy of prematurity and who were followed up for more than 12 months were analyzed retrospectively to ascertain clinical factors that may influence visual outcome. Vision was evaluated by preferential looking. Visual ability to discriminate stationary objects was obtained in 32 (58.2%) eyes, 18 (32.7%) had motion perception, and five (9.1%) had light stimulus perception. Although visual acuities were relatively low, they were useful to these patients. Age at the time of vitrectomy and the shape of the retinal detachment were found to be important factors in predicting visual prognosis.

Development of vision in retinopathy of prematurity.

Serial measures (range, two to eight) of preferential-looking grating acuities of 52 infants with retinopathy of prematurity were made. Group 1 patients (n = 11), who had little or no macular displacement, had normal preferential-looking acuity except for two who had mild acuity deficits. None of the group 2 patients (n = 12), who had dragged maculas, ever had normal acuity. On the average, their acuities, which ranged from 1 to 6 octaves less than normal, gradually increased at a rate not significantly different from normal. Group 3 patients (n = 29), who had undergone open-sky vitrectomy, had significantly lower acuity despite reattachment of the retina.

Retinal detachments in incontinentia pigmenti.

We report on retinal detachments in six eyes of four patients with incontinentia pigmenti. These nonrhegmatogenous traction retinal detachments are characterized by extensive preretinal and vitreous fibrous organization that pull the retina anteriorly behind the lens. The clinical course and fundus appearance of the retinal detachments, beginning with the avascular peripheral retina and leading to traction retinal detachment, are similar to those of cicatricial retinopathy of prematurity. Vitreous surgery was performed on three eyes (two patients), with partial reattachment of a total retinal detachment in one eye and complete reattachment of a partial retinal detachment in a second eye. These cases represent the first successful surgical interventions reported for retinal detachment in incontinentia pigmenti.

Pattern reversal visual-evoked response as a prognostic indicator in macular gliosis.

We recorded the preoperative pattern reversal visual-evoked responses in 16 subjects (16 eyes) with macular gliosis who underwent membrane-peeling operations. A postoperative visual improvement of one octave or more was observed in 11 of 16 eyes (68.8%). Preoperatively, ten eyes had peak amplitudes greater than or equal to 2 microV, all 11 eyes had either lowpass or bandpass curve shapes, and ten eyes had recordable responses to 20- or 10-minutes of an arc check sizes. Each of the three preoperative criteria was significantly associated with a postoperative visual improvement of one octave or more (P = .01, .02, and .02, respectively). These results demonstrate that the preoperative pattern reversal visual-evoked response can objectively assess the function of the underlying macula in patients with macular gliosis and, consequently, is helpful in determining which patient would most likely benefit from a membrane-peeling operation.

Early repolarization on scalar electrocardiogram.

Sixty thousand electrocardiograms were analyzed for 5 years. Six hundred (1%) revealed early repolarization (ER). Features of ER were compared with race-, age-, and sex-matched controls (93.5% were Caucasians, 77% were males, 78.3% were younger than 50 years, and only 3.5% were older than 70). Those with ER had elevated, concave, ST segments in all electrocardiograms (1-5 mv), which were located most commonly in precordial leads (73%), with reciprocal ST depression (50%) in a VR, and notch and slur on R wave (56%). Other results included sinus bradycardia in 22%, shorter and depressed PR interval in 38%, slightly asymmetrical T waves in 96.7%, and U waves in 50%. Sixty patients exercised normalized ST segment and shortened QT interval (83%). In another 60 patients, serial studies for 10 years showed disappearance of ER in 18%, and was seen intermittently in the rest of the patients. The authors conclude that in these patients with ER: 1) male preponderance was found; 2) incidence in Caucasians was as common as in blacks; 3) patients often were younger than 50 years; 4) sinus bradycardia was the most common arrhythmia; 5) the PR interval was short and depressed; 6) the T wave was slightly asymmetrical; 7) exercise normalized ST segment; 8) incidence and degree of ST elevation reduced as age advanced; 9) possible mechanisms of ER are vagotonia, sympathetic stimulation, early repolarization of sub-epicardium, and difference in monophasic action potential observed on the endocardium and epicardium.

Combined effects of cocaine and nicotine on cardiovascular performance in a canine model.

BACKGROUND: With the proliferation of cocaine abuse, increased incidence of catastrophic cardiovascular events such as angina pectoris, myocardial infarction, ventricular arrhythmias, or sudden death are reported. Many of these patients also smoke cigarettes before and after cocaine use, leading to a high frequency of simultaneous exposure to both drugs. Cocaine's and nicotine's independent effects on cardiodynamics are well documented, but combined effects of both on complete cardiovascular hemodynamics remain unknown. HYPOTHESIS: The study aimed to determine whether these effects are additive, synergistic, or antagonistic and was therefore designed to investigate the cardiovascular changes produced as a result of combined administration of cocaine and nicotine in a canine model. METHODS: Initially, in phase 1, 30 experiments were performed to study the dose-response curve of both drugs. In phase II and III, 12 dogs were subjected to 30 experiments. In phase II, cocaine was given intravenously (IV) followed by nicotine. In phase III, sequence of drug administration was reversed to study the effects on hemodynamics and coronary artery blood flow reserve. RESULTS: Hemodynamic parameters observed were Phase I: Dose-response curve established the IV bolus dose of cocaine 2 mg/kg and nicotine 50 microg/kg. Phase II: Cocaine increased heart rate, blood pressure, and dP/dt, but nicotine administration after cocaine produced marked significant synergistic excitatory effects: dP/dt increased from 1,810 +/- 210 to 6,300 +/- 460 (p < 0.003). Phase III: Nicotine significantly increased heart rate, mean arterial pressures, left ventricular end-diastolic pressure, pulmonary artery, pulmonary capillary wedge, and right atrial pressures. Nicotine increased dP/dt (1,810 +/- 192 to 5,000 +/- 160 mmHg/s; p < 0.004). These excitatory effects of nicotine were attenuated by cocaine when administered as a second drug (dP/dt decreased to 1,925 +/- 144 from 5,000 +/- 160 mmHg/s;p < 0.004). CONCLUSIONS: Cocaine, when administered alone, caused increase in heart rate, blood pressure, and dP/dt, but nicotine showed a significant increase in all the hemodynamic parameters. Both drugs reduced coronary blood flow reserve. In combination, cocaine plus nicotine administration had synergistic excitatory effects in dogs. A reversed drug combination, that is, nicotine plus cocaine, attenuated the excitatory effects of nicotine.

Left atrial abnormality by electrocardiogram predicts left ventricular hypertrophy by echocardiography in the presence of right bundle-branch block.

BACKGROUND: Left ventricular hypertrophy (LVH) on the electrocardiogram (ECG) may be masked in the presence of complete right bundle-branch block (RBBB). Left bundle-branch block on the ECG is associated with LVH at autopsy in 93% of hearts studied. However, RBBB does not predict LVH and the usual ECG criteria applied for LVH may not be reliable in the presence of RBBB. HYPOTHESIS: The study was undertaken to evaluate left atrial (LA) abnormality as a criterion for the diagnosis of LVH in the presence of RBBB. METHODS: Left atrial abnormality in the ECG was assessed by two independent observers as a criterion of LVH in the presence of RBBB in 100 patients, and data were compared with those of 50 patients without LA abnormality. RESULTS: Left ventricular hypertrophy was confirmed by echocardiographic determination of left ventricular (LV) mass in both groups. Observers reliably differentiated between hypertrophied and normal-sized LV in the presence of RBBB by using LA abnormality as an ECG criterion when correlated with LV mass determined by echocardiography. Observer 1 correctly detected LVH in 88% and Observer 2 in 82% of patients. False positive diagnosis was made in 12 and 18% of patients by Observers 1 and 2, respectively. Observers' performance of recognition of LA abnormality in the present study was 94%. Results showed sensitivity of 76 and 70% and specificity of 84 and 92% for Observers 1 and 2, respectively. Left ventricular mass increased significantly and was diagnostic of LVH in 92% of patients with LA abnormality. Left ventricular mass was high in 84% of patients when corrected by body surface area. LVH in the presence of RBBB by the ECG was found in only seven patients (5%) when six commonly used conventional criteria of diagnosis of LVH by ECG were employed. Regression analysis found LA abnormality to be a strong independent predictor of increased LV mass. Multiple regression analysis revealed that age, body mass index, body surface area, and frontal axis are also significant predictors of LV mass. CONCLUSION: The results obtained by the correlation of LA abnormality by ECG and LVH by echocardiography conclude that LA abnormality by ECG was significantly diagnostic of LV hypertrophy in the presence of RBBB.

Caffeine and cardiac arrhythmias. An experimental study in dogs with review of literature.

In spite of widespread belief among clinicians that caffeinated drinks are linked with palpitations, tachycardia and dysrhythmia there is paucity of documentary evidence. We investigated the arrhythmogenic activity of caffeine in canine model. The alkaloid was given i.v. to perform 51 experiments in 13 anesthetized dogs in three different doses. The Low dose generated significant Sinus (S) bradycardia (70%; p < 0.006, S. arrhythmia (70%; p < 0.02), S. arrest (50%; p < 0.04), Atrial (A) ectopics (40%; p < 0.016), Wandering of pacemaker (WPM) (50%; p < 0.04), and Ventricular premature contractions (VPC--unifocal 40%; p < 0.05) as compared with control ECGs. Medium dose induced significant S. arrhythmia (62%; p < 0.001), A. ectopics (25%; p < 0.01), A. tachycardia (25%; p < 0.01), WPM (25%; p < 0.01), VPCs--unifocal (50%; p < 0.002), multifocal (25%; p < 0.01), couplets (25%; p < 0.01) and interpolated (25%; p < 0.01). High dose of caffeine revealed significant S. arrhythmia (56%; p < 0.002), A. ectopics (44%; p < 0.005), A. tachycardia (32%; p < 0.01), WPM (32%; p < 0.01) and VPCs--unifocal (64%; p < 0.001), multifocal (32%, p < 0.01), couplets (32%, p < 0.01), interpolated (32%; p < 0.01) and Ventricular tachycardia (VT) (20%; p < 0.01). A. flutter and fibrillation each were observed in two experiments only. In conclusion, these data indicate a dose dependent arrhythmogenecity of caffeine. Small dose, mostly, generated, benign arrhythmias due to vagal stimulation. More severe arrhythmias like VT, multifocal VPC. A. flutter and A. fibrillation were generated with higher dose of caffeine. Mechanism remains uncertain as caffeine has multiple actions. Further studies in human beings with normal and compromised myocardium may elucidate arrhythmogenic effects of caffeine.

Alpha-1-antitrypsin in leprosy.

Estimation of Alpha-1-antitrypsin (AAT) levels was carried out in 52 patients of various types of leprosy. Fifty age and sex matched healthy individuals served as controls. The mean level of AAT in controls was 290.12 +/- 59.56 mg/dl. In patients of tuberculoid leprosy (TT), borderline tuberculoid leprosy (BT) and borderline leprosy (BB), the AAT levels were found to be 284 +/- 47.03, 314.37 +/- 31.56 and 324.44 +/- 32.05 mg/dl respectively. These were statistically insignificantly raised when compared with controls. In borderline lepromatous leprosy (BL), lepromatous leprosy without erythema nodosum leprosum (LL without ENL) and in LL with ENL there was a statistically significant rise in AAT levels. The maximum levels of AAT were observed in patients of LL with ENL (mean 500.8 +/- 93.44 mg/dl. P less than 0.001).

Correlation of electroretinographic and fluorescein angiographic findings in unilateral central retinal vein obstruction.

BACKGROUND: In central retinal vein obstruction (CRVO), electroretinogram (ERG) abnormalities and extensive retinal capillary dropout (CD) in the fluorescein angiogram (FA) are good indicators of retinal ischemia. We retrospectively studied patients with unilateral CRVO and compared the ERG and FA results. METHODS: Single white flash ERG, photopic ERG, scotopic ERG and flicker ERG were recorded in 30 cases of unilateral CRVO. We analyzed the correlation between the ERG results and the presence/absence of extensive CD. RESULTS: The ERG b/a-wave amplitude ratios, photopic and scotopic b-wave amplitudes, and flicker amplitudes were significantly smaller (P < 0.05) in eyes with extensive CD (n = 12, 40%), than in eyes without (n = 18, 60%). When the photopic or scotopic b-wave amplitudes were normal or supernormal, extensive CD on FA was absent in all eyes. When the b/a-wave ratios were > or = 1.0 or when the b-wave amplitudes with white flash or flicker amplitudes were normal or supernormal, extensive CD was present in less than 32% of eyes. CONCLUSION: These results suggest that the ERG results, especially the b/a-wave amplitude ratio, are significantly correlated with the presence/absence of CD on FA in CRVO.

Combined effects of caffeine and nicotine on cardiovascular hemodynamics in canine model.

The independent effects of caffeine and nicotine on cardiodynamics are well documented, but combined effects of both are not reported. Initially, in phase I, 18 experiments were performed to study the dose-response curve of both the drugs. In phases II and III, 13 mongrel dogs were subjected to 30 experiments. In phase II, caffeine, 5 mg/kg, was given i.v. followed by nicotine, 50 micrograms/kg, and in phase III, the sequence of drug administration was reversed to study the effects on hemodynamics. In phase II, caffeine did not show significant changes in all the cardiovascular parameters, but nicotine administration after caffeine produced marked significant synergistic excitatory effects: the rate of increase of the first derivative of left ventricular pressure (dP/dt) increased from 1,101 +/- 111 to 3,194 +/- 872 (p < 0.003). In phase III, nicotine significantly increased heart rate, mean arterial pressures; left ventricular end-diastolic pressure (LVEDP); and pulmonary artery, pulmonary capillary wedge, and right atrial pressures. Nicotine increased dP/dt (964 +/- 182 to 1,639 +/- 60 mm Hg/s; p < 0.004). The excitatory effects of nicotine were attenuated by administration of caffeine (dP/dt, 918 +/- 140 reduced to 715 +/- 144 mm Hg/s; p < 0.04). Caffeine and nicotine, alone, caused nonsignificant and significant increases in hemodynamics, respectively. In combination, caffeine + nicotine administration produced significant synergistic excitatory effects in dogs. On the other hand, the nicotine + caffeine combination caused attenuation by caffeine of the excitatory effects produced by nicotine.