Left ventricular geometry in pregnancy-induced hypertension.

The changes induced by transient hypertension upon cardiac geometry (G) are unclear. Pregnancy-induced hypertension (PIH) offers a natural and spontaneous model of this condition. To assess geometric changes according to two-dimensionally guided M-mode echocardiography, we compared patients with PIH with normal pregnant women (NPW). Fifty-five women, aged 28.5 +/- 7.5 years, with PIH (defined as blood pressure >140/90 mm Hg in the third trimester of pregnancy and without a history of hypertension) were compared with 57 NPW aged 30.7 +/- 7.5 years. Left ventricular mass index (LVMI) (Devereux formula) and relative wall thickness (RWT) (Ganau formula) were calculated by means of echocardiography done in the left lateral decubitus 2 to 4 days postpartum. Subjects were considered to have: normal geometry (NG) if both LVMI and RWT fell below the mean +/- 1 SD or 2 SD; concentric hypertrophy (CH) if both were elevated; eccentric hypertrophy (EH) if LVMI was elevated and RWT was normal; and concentric remodeling (CR) if LVMI was normal and RWT was elevated. Comparisons were performed by the Student t test. Patients with PIH had higher LVMI (106 +/- 29.4 v 90.6 +/- 19.8 g/m2; P < .05) and RWT (0.41 +/- 0.07 v 0.38 +/- 0.05; P < .05). Considering the mean +/- 1 SD of NPW as the limit of normality the G pattern was NG in 26 (47%) and abnormal in 29 (53%), of which 14 (25.5%) had EH, 11 (20%) had CR, and four (7%) had CH. If we considered the mean +/- 2 SD, the G pattern was NG in 46 (84%) and abnormal G in nine (16%), EH in four (7%), CR in three (5%), and CH in 2 (4%). According to these data, women with PIH had higher LVMI and RWT compared with NPW. The most frequent abnormal G patterns were EH and CR.

Left ventricular function impairment in pregnancy-induced hypertension.

The changes induced by transient hypertension on cardiac structure and function are unclear. Pregnancy-induced hypertension offers a natural and spontaneous model of this condition. To assess the potential of echocardiographic Doppler to unmask left ventricular function impairment, we studied 28 women aged 26.4 +/- 7.2 years with pregnancy-induced hypertension defined as blood pressure higher than 140/90 mm Hg in the third trimester of pregnancy without a history of hypertension. Twenty normal pregnant women, aged 27.5 +/- 6.4 years, were the controls. Left ventricular diastolic diameter, fractional shortening, E velocity, A velocity, E/A ratio, isovolumetric relaxation time (IRT), isovolumetric contraction time (ICT), ejection time (ET), and the combined index of myocardial performance (Tei index = IRT + ICT/ET), were calculated by echocardiography Doppler 2 to 4 days postpartum. There were statistically significant differences between groups in the following parameters: E/A ratio: 1.3 +/- 0.3 in pregnancy-induced hypertension v 1.5 +/- 0.3 in normal pregnant women (P < .05), IRT: 104 +/- 14 msec v 84 +/- 7 msec (P < .000), and the Tei index: 0.51 +/- 0.15 v 0.35 +/- 0.04 (P < .00), respectively. According to this data pregnancy-induced hypertension evaluated 2 to 4 days after delivery showed left ventricular dysfunction, mainly diastolic. The IRT and the Tei index are the most useful echocardiographic parameters to unmask left ventricular dysfunction in pregnancy-induced hypertension.

Thermoluminescence measurements of neutron dose around a medical linac.

The photoncutron ambient dose around a 18 MV medical electron lineal accelerator has been measured with LiF:Mg,Ti chips of 3 x 3 x 1 mm inside moderating spheres. During the measurements a water phantom was irradiated in a field of 40 x 40 cm2. Two methods have been considered for comparison. In the first, a TLD-600/TLD-700 pair at the centre of a 25 cm diameter paraffine sphere was used, with the system behaving as a rem meter. In the second method, TLD-600/TLD-700 pairs, bare and at the centre of 7.6, 12.7, 20.3, 25.4, and 30.5 cm diameter polyethylene Bonner spheres were used to obtain the neutron spectrum. This was unfolded using the BUNKIUT code with the SPUNIT algorithm and the UTA4 and ARKI response functions. The neutron dose was followed by multiplying the unfolded neutron spectrum by the ambient dose equivalent to neutron fluence conversion factors. Both methods result in 0.5 mSv x Gy(-1) m away from the isocentre.