24 ately horizontal. Rotation of the heart electrically in the combined groups was clockwise in 25 sub- jects and counterclockwise in 36, with about equal distribution between the exposed and unexposed groups. 4. RSTandT Waves. Abnormal variations were carefully noted for indications of coronaryor myocardial insufficiency and/or myocardial disease or damage. Deviations ofthe RST segment from the isoelectric line were found to be minimal; thev oc- curred in only five of the 84 unexposed subjects and in onlyone of the 38 exposed subjects. T wave abnormalities were of appreciable degree in only a few instancesin the older group. The abnormalities were chiefly in lower T waves and wererelated to hypertensive disease. T wave changes were most marked in a 51-year-old male ( #80) of the exposed group, who had arteriosclerotic heart dis- ease and auricular fibrillation. Marked RST and T wave changes were noted in an 81-year-old male (#46) of the exposed group, who had amount of arteriosclerosis was fairly well distributed between both populations, as can be seen in Table 14. [t was not observed in a degree premature or advanced for the given age. 2. Arterial Blood Pressures. Blood pressures greater than 140 systolic and 90 diastolic were considered abnormal. Onthis basis in the exposed group none of the 24 subjects <.50 ofage and seven of the 16 subjects >>50 had hypertension, but mostly of mild degree. There were 17 cases of hy- pertension in the unexposed group, 2 in those <(50 vears of age and 15 in those >50. The diastolic blood pressure showed only infrequent increase above the leve! of 90 mm; as would be expected, this occurred chiefly in the older group. The overall incidence of hypertension for the total popula- tion examined was 9.2%. Ed 3. Oscillometry Readings. Observations were taken on the legs at the mid-calf. In almost all subjects the pulstion was sufficient to indicate normal blood flow. Although the readings were lower in the Marshallese than might be expected in Caucasians, it appeared that peripheral vascu- marked hypertensive and arteriosclerotic cardio- vascular disease, and had prolonged auriculo- ventricular conduction time as noted above. Among the unexposed population there was evidence of myocardial insufficiency according to RST and T wave changes in a 51-year-old male (#947), a 64-year-old female { #861), a 55-yearold male ( #993), a 64-year-old female (#858), and a 64-year-old male (7884); the last had changes sufficient to indicate a healed anterior septal cardiac infarct. Other Cardiovascular Observations 1. Peripheral Vascular Findings. Clinical estimation was madeof the degree of arterial changes in the peripheral vessels (radial, brachial, and dorsalis pedis). The degree of abnormality was graded by 0 to 4+ sclerosis (see section on aging studies). Arterioscleraosis was seen chiefly in subjects >>50 year of age in both exposed and unexposed groups. It was not marked except in four individuals ~>70 Table 16 Ophthalmological Findings (% Incidence) Exposed Unexposed Pterygium Pinguecula Corneal pigment Corneal scars Arcus senilis Phthisis butbi Nvystagmus 23.0 24.0 12.0 9.0 38.0 1.3 1.3 21.0 22.0 2.6 3.4 26.0 0.0 0.7 Argyll-Robertson pupil Cataracts Aphakia Vitreous opacities Retinal arteriosclerosis Chorioretinal scars Macular degeneration Drusen Congenital anomalies 1.3 13.0 1.3 4.1 11.0 1.3 0.0 2.6 3.9 0.0 10.3 1.3 0.0 12.3 0.7 0.0 0.0 0.0 Strabismus 8.3 0.7 A group. The electrical position of the heartina gregt majority of both the unexposed and exposed subjects was vertical. In 22 subjects it was intermediate and in 9 (all unexposed) it was moder- > 70 vears of age for comparison, any assumption that the artertosclerosis was increased in these four individuals by their exposure to fallout radiation is unwarranted. Otherwise the presence and the wa unexposed group, and one in the older exposed vears of age in the exposed group, and thentoa degree compatible with age. Since there were no individuals examined in the unexposed group ann axis deviations normal or to the right in most individuals. Leftaxis deviation, and only of moderate degree, was present in six individuals, two in the younger unexposed group, three in the older