Interval In Women Research Articles

Interconceptional Antibiotics to Prevent Spontaneous Preterm Birth: A Randomized Clinical Trial

A large number of very early spontaneous preterm births are ascribed to bacterial infection of the upper genital tract or chorioamnionitis, without symptoms in either instance. Many believe that ascending infection by bacteria initially present in the cervix and vagina leads to microbial colonization of the chorioamnion and amniotic fluid. This study was an attempt to determine whether antibiotic treatment during the interpregnancy interval in women having a previous preterm birth before 34 weeks gestational age might lower the risk of spontaneous preterm birth in a subsequent pregnancy. A total of 241 women with a history of spontaneous birth before 34 weeks gestational age were randomized, in a double-masked trial, to receive either 2 1-g doses of azithromycin orally 4 days apart plus 750 mg daily of sustained-release metronidazole for 1 week or identical-appearing placebos. The regimen was repeated at 4-month intervals until a subsequent pregnancy began, as was the case for 124 women, 59 of whom received antibiotics. The antibiotic-treated and control women were similar in most respects, but the actively treated women were significantly more compliant in keeping study appointments and taking their assigned medications. Approximately 80% of women in both groups received a course of treatment within 6 months before the subsequent conception. Positive endometrial cultures at the time of randomization were comparably frequent in the antibiotic and placebo groups: 86% and 91%, respectively. Median numbers of individual microbial species isolated from the endometrium also did not differ significantly. Plasma cell endometritis was found in 31% of the antibiotic group and 47% of placebo recipients. Repeat endometrial cultures taken 2 weeks later showed a lower number of individual bacterial species in 49% of women given antibiotics and 31% of the control group. There was no apparent difference in the resolution of endometritis. The risk of a subsequent preterm birth did not differ significantly between the 2 groups, and the same was the case for miscarriage before 15 weeks gestation. Although not statistically significant, average gestational age at delivery was 2.4 weeks shorter in the antibiotic group, and average birth weight was 418 g lower than in the placebo group.

THE CLASSIC: Quantitative Computed Tomography of Vertebral Spongiosa: A Sensitive Method for Detecting Early Bone Loss after Oophorectomy

THE CLASSIC: Quantitative Computed Tomography of Vertebral Spongiosa: A Sensitive Method for Detecting Early Bone Loss after Oophorectomy

Normal Standards for QT and QT Subintervals Derived from a Large Ethnically Diverse Population of Women Aged 50 to 79 Years (the Women’s Health Initiative [WHI

Available normal standards for rate-adjusted QT intervals in women are based on samples that include only whites, and no normal standards are available for QT subintervals. This study derived normal limits from percentile distributions for QT as well as QT and T-wave subintervals in 22,311 participants in the Women's Health Initiative (WHI), including 19,059 white, 1,771 African-American, 819 Hispanic, 82 American Indian, and 580 Asian women. Excluded were women with cardiovascular disease or who were using cardioactive drugs at baseline and cardiovascular morbidity or death during the subsequent mean 6.3-year follow-up. Normal limits for QT adjusted by Bazett's formula were strongly rate dependent, invalidating their use in practical applications. QT adjusted as a linear function of RR (QTrr) or by power functions of RR with exponent 0.5 (QTsqr) or 0.42 (QT0.42) using an appropriate regression function produced rate-invariant upper and lower normal limits for rate-adjusted QT. Adjusted QT is preferable to adjusted JT because the latter requires the incorporation of QRS duration as a covariate with RR. Normal limits were also derived for T-wave subintervals. Normal limits of QTrr in Asian women were 10 ms longer than in other ethnic groups. In conclusion, QT adjusted for rate as a linear function of RR is preferable to JT and other QT subintervals in the evaluation of QT prolongation. The adaptation of considerable revisions of the currently used limits for prolonged QT in women is suggested, with an additional race-specific adjustment in Asian women. Bazett's formula is inappropriate for testing new drugs or other applications.

Sonographic myometrial thickness predicts the latency interval of women with preterm premature rupture of the membranes and oligohydramnios

Term labor is associated with global thinning of the myometrium. We hypothesized that a thickened myometrium at the time of preterm premature rupture of membranes (PPROM) predicts less myometrial wall stress and, consequently, a longer latency interval. Myometrial thickness was measured prospectively in 76 pregnant women enrolled in the following groups: PPROM (n=28, mean [range], gestational age [GA]: 29.5 weeks [w] [21.0 w-33.0 w]), preterm nonlabor control group (P-CTR), (n=21, GA: 27.5 w [23.0 w-32.0 w]) and term nonlabor control (T-CTR) (n=27, GA: 38.6 w [37.0 w-41.6 w]). All PPROM women had oligohydramnios (AFI: 1.4 cm [0.0 cm-5.1 cm]). MT was measured ultrasonographically at the midanterior, fundal, posterior, and lower uterine segment wall in cases and controls with an intraoperator variability <10%. Women in the PPROM group displayed uniform thickness of the uterine body (mean +/- SEM, anterior: 10.6 +/- 0.6 mm, fundal: 10.7 +/- 0.7 mm, posterior: 8.9 +/- 0.5 mm, P=.078). At midanterior site the myometrium of the PPROM group was thicker compared to both P-CTR (P < .001) and T-CTR (P=.025) groups. This difference was preserved at the fundus (PPROM vs P-CTR, P < .001; PPROM vs T-CTR, P=.015). There was a positive correlation between fundal MT and latency period (r=0.43, P=0.02) that persisted after adjusting for GA (P=.04). A fundal MT less than 12.1 mm was 93.7% sensitive and 63.6% specific for the identification of women whose latency period was less than 120 hours. Significant thickening of the anterior and fundal walls of the uterus follows PPROM. A thick myometrium in nonlaboring patients with PPROM is associated with longer latency interval. Sonographic evaluation of MT may represent an alternative clinical tool for the prediction of a short latency interval in women with PPROM.

The effect of vaginal pH on labor induction with vaginal misoprostol

Objective. To estimate the association of vaginal pH on the induction to vaginal delivery interval in labor induction with vaginal misoprostol.Methods. Women presenting at term with intact membranes for labor induction were recruited. The pH of the vagina was measured during a digital examination of the cervix to determine the Bishop Score. Labor was induced with 25 μg of vaginal misoprostol placed every 6 h until spontaneous rupture of membranes or active labor occurred. The primary outcome was the induction to vaginal delivery interval in the lower pH ( < 5) versus higher pH ( ⩾ 5) group. Secondary outcomes assessed maternal and neonatal morbidities. Sample size calculated a priori estimated 120 subjects were required for a power of 95% and a 2-tailed α of 0.05.Results. 120 women met inclusion criteria and had available pH data. There was no difference in the induction to vaginal delivery interval in the lower pH (1455 min) versus higher pH group (1295 minutes, Mean difference 160[−147,468] P =. 30). No difference was observed for operative delivery rates or neonatal outcomes.Conclusion. The pH of the vagina may not affect the length of the induction to vaginal delivery interval in women undergoing labor induction with vaginal misoprostol. Further research is required to determine factors that may influence the efficacy of vaginal misoprostol when used for labor induction.

Whole abdominal radiotherapy in the adjuvant treatment of patients with stage III and IV endometrial cancer: A gynecologic oncology group study

Objective To evaluate toxicity, survival, and recurrence-free interval in women with loco-regionally advanced endometrial carcinoma treated with postoperative whole abdominal radiation therapy. Methods Whole abdominal irradiation with pelvic plus or minus para-aortic boost was initiated within 8 weeks of total abdominal hysterectomy, bilateral salpingo-oophorectomy, pelvic washings, and selective pelvic and para-aortic node sampling in eligible, consenting patients. Results Of 180 evaluable patients entered on the study with surgically staged III and IV endometrial carcinoma maximally debulked to less than 2 cm, 77 had typical endometrial adenocarcinoma and 103 had high-risk histology, either papillary serous or clear cell carcinoma. Patients with typical endometrial adenocarcinoma were significantly younger and had significantly fewer poorly differentiated cancers. Proportionally, there were twice as many non-Whites with high-risk histologies as non-Whites with typical endometrial adenocarcinoma. Forty-five percent of patients with typical endometrial adenocarcinomas had positive pelvic nodes compared to 51% of those with high-risk histologies. Both histologic groups had similar distribution for performance status, para-aortic node positivity, site and extent of disease, and International Federation of Gynecology and Obstetrics (FIGO) stage. The frequency of severe or life-threatening adverse effects among 174 patients evaluable for radiation toxicity included 12.6% with bone marrow depression, 15% GI, and 2.2% hepatic toxicity. The recurrence-free survival rates were 29% and 27% (at 3 years) for the typical endometrial adenocarcinoma and high-risk histologies, respectively. The survival rates were 31% and 35%, respectively. No patient with gross residual disease survived. Conclusion Whole abdominal irradiation in maximally resected advanced endometrial carcinoma has tolerable toxicity, and it is suggested that the outcome may be improved by this adjunctive treatment in patients with completely resected disease.

ALCOHOL CONSUMPTION AND MIDLIFE COGNITIVE CHANGE IN THE BRITISH 1946 BIRTH COHORT STUDY

Cross-sectional studies suggest that alcohol consumption benefits cognitive function. However, more longitudinal studies are required to confirm that alcohol has an effect on cognitive change and to rule out the possibility that those of higher ability engage in a lifestyle that protects against cognitive decline. We investigated the association between self-reported alcohol consumption and change in memory, speed and concentration in midlife, in 903 men and 861 women enrolled in the MRC National Survey of Health and Development (the British 1946 birth cohort). After controlling for educational attainment, occupational social class and general cognitive ability, it was found that alcohol consumption was associated with a slower memory decline from 43 to 53 years in men, but a more rapid decline in visual search speed for the same interval in women. These effects were not explained by a further control for health status (body water weight, smoking, exercise, cardio-respiratory disease and affective state). Our data suggest that alcohol consumption is associated with a slower memory decline. However, the negative association between alcohol and psychomotor function in women is a potential cause for concern.

Changes in saccadic latencies over the human menstrual cycle.

The study assessed differences in sensorimotor processing as reflected in measurements of saccadic latencies at 3 different stages in the menstrual cycle (menstruation, early luteal, and premenstruation) in naturally cycling women (n = 13), and at the same time intervals in women taking an oral contraceptive (n = 6), and male controls (n = 8). Subjects (M age = 22.0 yr., SD = 2.2 yr.) were recruited by questionnaire from the student population of the University of Cambridge. Latencies were measured using a portable infrared scleral oculometer. Changes in latency across the menstrual cycle occurred only in the naturally cycling women (F(2.11) = 5.95, p < .05). Premenstrual latencies were greater (199.3 +/- 12.7 msec., M +/- SD) compared to those during menstruation (191.9 +/- 11.1 msec.) or midcycle (196.9 +/- 12.7 msec.). These findings could account for the loss of musculoskeletal coordination reported by some women prior to menstruation and suggests that administration of an oral contraceptive may alleviate this effect.

Risk of proarrhythmia with class III antiarrhythmic agents: sex-based differences and other issues

Although men have a higher risk of atrial fibrillation compared with women, the absolute number of women with atrial fibrillation is greater. Congestive heart failure increases the risk of developing atrial fibrillation in women more than in men, and the prognosis for women with atrial fibrillation is worse than for men. The longer baseline corrected QT interval in women is well known. The mechanism is likely the result of increased circulating androgens, causing the QT interval to shorten in men after puberty. Female sex is associated with an increased risk of torsades de pointes in the setting of potassium antagonists. Class III antiarrhythmic drugs are frequently used for the treatment of atrial fibrillation in heart failure patients because of their neutral effect on mortality and their tolerance by patients with low ejection fractions. Although amiodarone and azimilide carry a low potential for producing torsades de pointes compared with sotalol and dofetilide, the prevalence of torsades de pointes in women is at least twice that in men for all these drugs. Careful monitoring of the QT interval and potassium level, as well as control of congestive heart failure, can help reduce the risk of proarrhythmia. Avoidance of polypharmacy with other potassium antagonists and unmonitored drug formulation changes are important in the management of all patients taking class III agents, but they are particularly crucial in women with additional risk factors for torsades de pointes.

Inhibin-A and superimposed preeclampsia in women with chronic hypertension

Objective To determine if maternal serum inhibin-A can be used as a marker for subsequent development of superimposed preeclampsia in women with chronic hypertension. Methods Serum for measurement of inhibin-A was obtained at monthly intervals in women with chronic hypertension requiring antihypertensive medications. Superimposed preeclampsia, the primary outcome of interest, was diagnosed when hypertensive women developed proteinuria (at least 300 mg per 24-hour urine specimen). Serum inhibin-A was considered abnormally elevated when the value exceeded the mean plus two standard deviations of the log for chronically hypertensive women who did not develop preeclampsia. Results A total of 61 women were enrolled in this study, and 21 (34%) developed superimposed preeclampsia. Inhibin-A levels increased with advancing gestational age. Ten women had abnormally increased inhibin-A levels; eight (80%) developed superimposed preeclampsia, compared with 13 of 51 (26%) women with normal inhibin-A levels ( P < .001). Sensitivity and specificity were 38% and 95%, respectively, whereas the positive and negative predictive values were 80% and 75%, respectively. Conclusion Although inhibin-A was abnormally increased an average of 3 weeks before the clinical onset of superimposed preeclampsia, the sensitivity of the test as a screen was too limited to be clinically useful.

Biologic and molecular mechanisms for sex differences in pharmacokinetics, pharmacodynamics, and pharmacogenetics: Part I.

There are pharmacological differences between women and men that have important clinical consequences. For several drugs, there is a higher incidence in women of drug-induced QT prolongation and a potentially fatal arrhythmia, torsades de pointes. This may be a reflection of the longer baseline QT interval in women. A difference in cardiovascular disease between women and men is that women have a higher mortality rate after myocardial infarction (MI). Women also have a higher rate of hemorrhagic stroke after receiving thrombolytic therapy for an MI. Differences in effectiveness of analgesics have been demonstrated, with kappa opioids providing pain relief for women but not men. Drugs may have different pharmacokinetics in women and men because of differences in phase I and phase II enzymes that metabolize drugs. Conflicting results about biological sex differences have been reported for the major drug metabolizing enzyme, cytochrome P450 3A4 (3A4) and may be related to a role for P-glycoprotein, a cell membrane transporter, reported as two times higher in male livers than those of females. It has been reported that boys need a higher dose of 6-mercaptopurine, which is metabolized by thiopurine methyltransferase (TPMT). TPMT is reported to be 14% higher in male human liver biopsies than those from females. Verapamil, a drug for angina and hypertension, has different clearance and side effects in men and women. Ethnic/racial variations have also been demonstrated with the drug metabolizing enzymes, CYP2C9, 2C19, and 2D6.

The effect of extending the pill-free interval on follicular activity: triphasic norgestimate/35 μg ethinyl estradiol versus monophasic levonorgestrel/20 μg ethinyl estradiol

This study was designed to evaluate follicular activity in women taking oral contraceptives with imposed imperfect compliance. After completing a 28-day cycle of either triphasic norgestimate/EE (NGM/EE) (Ortho Tri-Cyclen, Ortho-McNeil Pharmaceutical, Raritan, NJ) or monophasic levonorgestrel/EE (LNG/EE) (Alesse, Wyeth-Ayerst Laboratories, Philadelphia, PA), women were instructed to intentionally “miss” the first two active pills of the next pack. The first two tablets in the second treatment cycle were deliberately omitted, thereby extending the pill-free interval from 7 days to 9 days. Subjects were randomized to take NGM/EE (n = 40) or LNG/EE (n = 39) for two consecutive cycles. The mean maximum follicular diameter was significantly greater in women taking LNG/EE than in those taking NGM/EE (16.4 ± 7.1 mm vs. 12.6 ± 8.3 mm, p = 0.047). The LNG/EE group had significantly higher median serum estradiol concentrations compared to women taking NGM/EE on pill Days 10 [29.5 pg/mL (range: 10.0–540.0 pg/mL) vs. 2.5 pg/mL (range: 2.0–6.0 pg/mL), p < 0.001] and 14 [11.0 pg/mL (range: 2.0–416.0 pg/mL) vs. 2.0 pg/mL (range: 2.0–3.0 pg/mL), p = 0.001]. Two women in the NGM/EE group and three women in the LNG/EE group had at least one progesterone level ≥3 ng/mL; none of these women demonstrated a maximum follicular diameter >13 mm. Significantly greater follicular activity was observed after an extended pill-free interval in women taking LNG/EE compared to those taking triphasic NGM/EE. The clinical implications of these findings require further study.

Laminaria versus extra-amniotic saline solution infusion for cervical ripening in second-trimester labor inductions

Objective: The aim of this study was to determine which cervical ripening method, laminaria placement or extra-amniotic saline solution infusion, was associated with the shorter interval from induction to delivery in the second trimester. Study Design: Women admitted for indicated second-trimester labor induction with an unfavorable cervix were randomly assigned to receive either intracervical placement of laminaria (n = 25) or extra-amniotic saline solution infusion (n = 25) with concurrent concentrated oxytocin and vaginally administered prostaglandin E2 (10 mg every 6 hours). Treatment success was defined as an interval from induction to delivery of ≤24 hours. Results: Maternal age, race, parity, gestational age, and initial cervical dilatation were similar between the groups. Indications for uterine evacuation were also similar and included fetal death (n = 7), aneuploidy (n = 20), fetal structural anomaly (n = 18), and maternal indications (n = 4). There was no difference in the mean intervals from induction to delivery (laminaria, 16 ± 8 hours, vs extra-amniotic saline solution infusion, 17 ± 10 hours) or the number of treatment successes (laminaria, n = 23, vs extra-amniotic saline solution infusion, n = 21). Retained placenta, live birth, and hemorrhage occurred with similar frequencies in the two groups. Conclusion: Relative to laminaria, extra-amniotic saline solution infusion did not shorten the induction-to-delivery interval in women undergoing indicated second-trimester labor induction with concentrated oxytocin and low-dose vaginally administered prostaglandin E2. (Am J Obstet Gynecol 2001;184:1145-8.)

Effects of estrogen on action potential and membrane currents in guinea pig ventricular myocytes.

To explore a possible ionic basis for the prolonged Q-T interval in women compared with that in men, we investigated the electrophysiological effects of estrogen in isolated guinea pig ventricular myocytes. Action potentials and membrane currents were recorded using the whole cell configuration of the patch-clamp technique. Application of 17beta-estradiol (10-30 microM) significantly prolonged the action potential duration (APD) at 20% (APD(20)) and 90% repolarization (APD(90)) at stimulation rates of 0. 1-2.0 Hz. In the presence of 30 microM 17beta-estradiol, APD(20) and APD(90) at 0.1 Hz were prolonged by 46.2 +/- 17.1 and 63.4 +/- 11.7% of the control (n = 5), respectively. In the presence of 30 microM 17beta-estradiol the peak inward Ca(2+) current (I(CaL)) was decreased to 80.1 +/- 2.5% of the control (n = 4) without a shift in its voltage dependence. Application of 30 microM 17beta-estradiol decreased the rapidly activating component of the delayed outward K(+) current (I(Kr)) to 63.4 +/- 8% and the slowly activating component (I(Ks)) to 65.8 +/- 8.7% with respect to the control; the inward rectifier K(+) current was barely affected. The results suggest that 17beta-estradiol prolonged APD mainly by inhibiting the I(K) components I(Kr) and I(Ks).

Maternal age-specific risk of Down syndrome in an Asian population: a report of the Taiwan Down syndrome screening group

This study is a novel approach in establishing the maternal age-specific risk for Down syndrome screening in an Asian population. The relative frequency by one-year maternal age interval in women who had live births in the Taiwan area between 1975 and 1995 was used as the age-specific distribution of women who had unaffected pregnancies. Data about Down syndrome live births were obtained from the Taiwan Down Syndrome Association to establish the age distribution of women who had Down syndrome live births. The relative frequencies and the likelihood ratio by one-year maternal age interval was calculated and smoothed by running median and moving average smoothing methods. The age-specific risk was established by multiplying the total population risk by the likelihood ratio of the specific maternal age. The total live births in the Taiwan area between 1975 and 1995 were 7,232,689. A total of 527 cases of Down syndrome live births were registered in the Taiwan Down Syndrome Association. A total of 466 cases (88.43 per cent) of Down syndrome live births occurred before age 35, which was higher than occidental reports. This study established the first sizeable database of maternal age-specific risk for Down syndrome in an Asian population.

Effects of gender on cardiac arrhythmias.

The purpose of this study is to review published data regarding gender differences in cardiac electrophysiology and in the occurrence of clinical arrhythmias. ECG differences between men and women include a faster resting heart rate in women, a longer corrected QT interval, and a lower QT dispersion than in men. The faster resting heart rate in women appears to be primarily related to differences in physical conditioning. The mechanism for the longer corrected QT interval in women is not completely known, but does not appear to be related to acute effects of estrogen or progesterone or differences in autonomic innervation. Women also appear to have a lower incidence of atrial fibrillation, a difference in the age distribution of supraventricular tachycardia, and a lower incidence of sudden death than men. Much of the lower incidence of sudden death in women may relate to a difference in the prevalence of coronary artery disease, but other factors such as inherent differences in repolarization, which may be reflected by a gender difference in the corrected QT interval, also may be operative. The paradox of a longer corrected QT interval and higher incidence of torsades de pointes, but lower population-based incidence of sudden death in women, has not been completely resolved. Further studies will be required to help better understand the basic mechanisms involved in gender differences in electrophysiology and arrhythmias and determine the extent to which these differences have implications for clinical management of cardiac arrhythmias.

Reference intervals for serum cystatin C and serum creatinine in adults.

The aim of this study was to establish reference intervals for cerum cystatin C and serum creatinine in adults. Blood samples were collected from 270 healthy blood donors (135 men and 135 women between 20 and 65 years old with 15 men and 15 women in each five-year-interval). Serum cystatin C was analyzed using an automated particle-enhanced immunoassay (DAKO Cystatin C PET kit) on the Cobas Mira S analyzer. Serum creatinine was analyzed using the Vitros Creatinine Slide, an enzymatic method on the Vitros 950 chemistry analyzer. The calculated reference intervals for serum cystatin C were 0.62-1.15 mg/l in women (median 0.84 mg/l, range 0.56-1.29 mg/l) and 0.51-1.25 mg/l in men (median 0.87 mg/l, range 0.42-1.39 mg/l). The Mann-Whithey U-test revealed no gender-related difference for cystatin C (p = 0.48). A common reference interval in women and men was calculated to be 0.54-1.21 mg/l (median 0.85 mg/l, range 0.42-1.39 mg/l). The non-parametric reference interval for serum creatinine was 57-95 mumol/l in women (median 72 mumol/l, range 44-105 mumol/l) and 69-111 mumol/l in men (median 89 mumol/l, range 58-123 mumol/l).

Dimeric Inhibin Serum Values as Markers of Ovarian Activity in Pill-Free Intervals

Levels of inhibin A and B as well as other hormones in serum samples obtained during the pill-free interval in women taking combined oral contraceptives (OC) were measured to asses the extent of ovarian activity during that period. Type of pill and day of pill-free interval were recorded during routine gynecologic check-ups, if patients were in the pill-free period and had taken their pills regularly in the previous cycle. In addition to inhibin A and B, serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E 2), and progesterone were also quantified. Inhibin B levels rise significantly in parallel with rising levels of FSH, LH, and E 2. Progesterone levels were completely suppressed and inhibin A levels rose slightly but insignificantly. Inhibins are sensitive biochemical markers of ovarian activity in pill-free intervals.

Effect of obesity and regional adiposity on the QTc interval in women

To determine whether differences in body fat composition and body fat distribution patterns are associated with a prolongation of the corrected QT interval for heart rate (QTc) on the electrocardiogram (EKG) during rest and exercise. Cross-sectional evaluation of the Qtc interval in three groups of premenopausal women during rest and two exercise conditions (50% VO2 max and VO2 max). Thirty-one healthy women with a mean age of 35 y (27-44 y) were classified as either obese (n = 22; percent body fat [%BF] > 30%) or nonobese (NO; n = 9; %BF < or = or 27%) by hydrostatic weighing. Obese subjects matched for age and %BF were grouped by waist to hip ratio (WHR) into two groups: upper body obesity (UBO; n = 11; WHR > or = 0.85) and lower body obesity (LBO; n = 11; WHR < or = 0.75. RR and QT intervals were measured in a double-blind design with the aid of calipers and magnifying lens for seven consecutive beats in lead II from a 12-lead EKG at a paper speed of 25 mm/sec. Five consecutive cardiac cycles excluding the longest and shortest RR and QT intervals were averaged and calculated for QTc interval using Bazett's formula. Mean QTc intervals were significantly different (P < 0.001) across the groups for each condition. For all conditions, UBO had the longest QTc interval as compared to LBO and NO respectively (i.e., Rest: 0.426; 0.413; 0.399sec1/2, Mid50%: 0.447; 0.426; 0.409sec1/2; Max: 0.390; 0.374; 0.357sec1/2). The QTc interval is positively associated with UBO even at the same level of body fat in moderately obese women. It is clear that abdominal obesity may be one of the risk factors for a prolonged QTc interval in premenopausal women.

Heart rate-independent prolongation of QTc interval in women with syndrome X

Cardiac syndrome X is usually diagnosed in the presence of typical exertional chest pain, a positive response to exercise testing, and normal coronary angiograms. The underlying pathogenic mechanisms are speculative, but myocardial ischemia and increased sympathetic activity have been implicated. The present study examined whether QTc interval is prolonged in women with syndrome X when confounding factors such as heart rate, gender, and environmental conditions are accounted for. Maximum QTc interval and its relationship to clinical and exercise variables were evaluated in 32 women with syndrome X (exertional chest pain, positive exercise testing, and completely normal coronary arteries) and 34 normal controls. Patients with syndrome X had significantly longer QTc interval (440 +/- 24 ms) than normal subjects (410 +/- 26 ms, p < 0.004). However, this QTc prolongation appears to be heart rate-independent as patients with syndrome X showed longer QT and QTc intervals than controls despite an identical heart rate. No relation was found between QTc prolongation and clinical or exercise test variables in patients with syndrome X. Although increased sympathetic drive is present in syndrome X, and this variable is likely to modulate QTc duration, the mechanism and clinical implications of QTc interval prolongation in syndrome X remain speculative.