Restrictive left ventricular filling pattern and risk of new-onset atrial fibrillation after acute myocardial infarction

Mechanisms for atrial arrhythmias that occur in the context of acute myocardial infarction (AMI) have not been well characterized. AMI often leads to alterations in left ventricular (LV) filling dynamics, which may result in advanced diastolic dysfunction. Diastolic dysfunction may produce increased left atrial (LA) pressure and initiate LA remodeling, promoting the progression to atrial fibrillation (AF). We studied 1,169 patients admitted with AMI. Advanced diastolic dysfunction was defined as a restrictive filling pattern (RFP), defined as ratio of early to late transmitral velocity of mitral inflow >1.5 or deceleration time <130 ms. The relation between RFP and the primary end point of new-onset AF occurring within 6 months was analyzed using multivariable Cox models. Of 1,169 patients (70% men, mean ± SD 64 ± 10 years of age), 110 (9.4%) developed new-onset AF (19.6% and 7.5% in patients with and without RFP, respectively, p <0.0001). RFP was associated with a hazard ratio of 2.72 for AF (95% confidence interval 1.83 to 4.05, p <0.0001). After multivariable adjustments for clinical variables, LV ejection fraction (EF) and LA size, RFP remained an independent predictor of AF (hazard ratio 2.17, 95% confidence interval 1.42 to 3.32, p <0.0001). Risk of AF was higher in patients with RFP for preserved (≥45%, hazard ratio 2.14, 95% confidence interval 1.09 to 4.20, p = 0.03) or decreased (hazard ratio 2.80, 95% confidence interval 1.63 to 4.82, p <0.0001) LVEF. In contrast, decreased LVEF in the absence of RFP was similar to that of patients with preserved LVEF and without RFP. In conclusion, in patients with AMI, presence of advanced diastolic dysfunction was independently associated with new-onset AF, suggesting that increased filling pressures may contribute to the development of AF after AMI.     

Migration is associated with lower total, but not free testosterone levels in South Asian men

OBJECTIVE: Serum testosterone measurement is an integral part of the endocrine assessment of men. Little is known about its variation in relation to migration. We examined within a South Asian group the effect of migration to the UK on androgen levels. DESIGN: Circulating testosterone and SHBG concentrations were measured in 97 Gujarati men resident in India and in 79 men from the same villages of origin living in Birmingham, UK. Free testosterone was calculated by Vermeulen's method. Insulin sensitivity (HOMA-S) was determined from paired fasting plasma intact insulin and glucose values. RESULTS: Circulating testosterone was significantly lower in UK Gujarati men (17.2 nmol/l [15.7-18.7]) vs. Indian Gujarati men (21.7 [20.0-23.5]) (P = 0.0002) (age-adjusted median [95% CI]). There was no difference by migration status in circulating free testosterone. Sex hormone binding globulin (SHBG) levels were lower in UK migrants (16.8 nmol/l [15.5-18.1]) than in nonmigrants (21.9 nmol/l [20.5-23.3]) (P < 0.0001). Testosterone level correlated positively with insulin sensitivity (HOMA-S) (rho 0.16, P = 0.04). In multivariate analysis, total testosterone was independently and positively associated with logSHBG (normalized beta (beta) = 0.29, P = 0.002) and independently and negatively with waist circumference (beta = -0.19, P = 0.04), in a model also including height, age, migration status, leptin and fasting insulin. CONCLUSION: Lower circulating testosterone in UK Gujarati men and its association with markers of insulin sensitivity suggest a profound influence of body composition change with migration on testosterone levels. The lower SHBG in this group restores parity in free testosterone. Account should be taken of SHBG in interpreting testosterone levels in men, as well as in women.     

Platelet-free calcium and vascular calcium uptake in ethanol-induced hypertensive rats

This study examined the effect of moderate ethanol intake on systolic blood pressure, platelet cytosolic free calcium, aortic calcium, and rubidium-86 uptake in Wistar-Kyoto rats. Twelve Wistar-Kyoto rats, aged 6 weeks, were given 5% ethanol in drinking water the first week followed by 10% ethanol in drinking water for the next 6 weeks. Twelve control animals were given regular tap water. Systolic blood pressure in the ethanol-treated rats was significantly higher (p less than 0.05) than that in controls after 1 week and remained higher throughout the study. At 13 weeks of age, platelet cytosolic free calcium and calcium uptake by aortas were significantly higher (p less than 0.001) in ethanol-treated animals as compared with those in controls. Ethanol intake did not affect aortic ouabain-sensitive 86Rb uptake. The in vitro effect of ethanol on calcium-45 and 86Rb uptake was also investigated in aortas of untreated Wistar-Kyoto rats at 13 weeks of age. In vitro ethanol (2.5-20 mmols/l) did not significantly affect 45Ca and 86Rb uptake in rat aortas. The increases in systolic blood pressure, platelet cytosolic free calcium, and vascular calcium uptake suggest that increases in cytosolic free calcium and calcium uptake mechanisms are associated with ethanol-induced hypertension.     

Diffusion of cancer education information through a Latino community health advisor program

OBJECTIVE: To examine diffusion of breast and cervical cancer screening information through a community health advisor program targeting Latino women of low socioeconomic level and low level of acculturation in San Diego, California. METHOD: Seventeen community health advisors ("consejeras") were recruited and trained to conduct educational group sessions. Each consejera recruited peers from the community to participate in the 12 sequential weekly sessions (i.e., primary participants). In addition, each of the primary participants identified up to two friends and/or family members (i.e., "learning partners") with whom they intended to share the cancer education information received. Pretest and posttest telephone surveys were conducted between 1996 and 1997. A total of 311 primary participants completed the pretest and 285 the posttest. Among the learning partners, 269 completed the pretest and 222 the posttest. RESULTS: Knowledge about breast and cervical cancer and self-reported use of screening tests increased among primary participants and learning partners. However, the increase was not statistically significant in mammography screening among participants 40 years old or older. Overall, increases in knowledge were more pronounced among primary participants when compared to learning partners. CONCLUSION: The utilization of the learning partner model represents a promising diffusion tool to enhance cancer early detection programs relying on community health advisors.     

Why might South Asians be so susceptible to central obesity and its atherogenic consequences? The adipose tissue overflow hypothesis

The rates of coronary disease have accelerated dramatically amongst South Asians, driven to an important extent by the atherogenic dyslipidemia and type 2 diabetes that have become so common amongst them. These precursors of vascular disease appear at lower absolute amounts of adipose tissue in South Asians than in whites. In this paper, we set out a new hypothesis--the adipose tissue overflow hypothesis--to account for these findings. The adipose tissue mass within our bodies can be divided into three different compartments: superficial subcutaneous adipose tissue, deep subcutaneous adipose tissue and visceral adipose tissue. The superficial subcutaneous adipose tissue compartment is the primary compartment, is present throughout the body, and constitutes the vast majority of the adipose tissue in the lower limb. With energy excess, the secondary adipose tissue compartments--the deep subcutaneous (mainly upper body) and the visceral adipose tissue compartments--become more prominent. Superficial subcutaneous adipose tissue is relatively inert metabolically, whereas the other two compartments are characterized by higher transmembrane fatty acid flux rates and thus are more closely linked to dyslipidemia and dysglycemia. We hypothesize that the superficial subcutaneous adipose tissue compartment is larger in whites than in South Asians. If so, as obesity develops, South Asians exhaust the storage capacity of their superficial subcutaneous adipose tissue compartment before whites do and that is why they develop the metabolic complications of upper body obesity at lower absolute masses of adipose tissue than white people.     

Application of lot sampling of sputum AFB smears for the assessment of microscopy centres.

SETTING: Designated microscopy centres (DMC) and additional microscopy centres (AMC) performing sputum acid-fast bacilli (AFB) microscopy, the District TB Centre (DTC) and a reference laboratory (RL). OBJECTIVES: To ascertain the feasibility of adopting lot sampling of AFB smears and to assess the performance of MCs employing Senior Tuberculosis Laboratory Supervisors (STLS) with no knowledge about the principles of quality assurance of AFB microscopy and RL-based laboratory technicians with training on quality assurance for blinded checking of AFB smears. METHODS: Slides from MCs were transported to the DTC and the RL; 20 smears per month per MC were selected systematically; 1547 slides from DMCs and 726 from AMCs were checked, respectively, by STLSs at the DTC and by RL laboratory technicians. Discrepancies were resolved by referee. RESULTS: The discrepancy between MC laboratory technicians and STLSs at the DTC was 4.7%, compared to 1% at the RL. The STLSs and RL-based laboratory technicians had 70 and 2 errors, respectively. CONCLUSIONS: Lot sampling of AFB smears is feasible under field conditions. Assessment of MCs was more valid with RL-based technicians trained in principles of quality assurance of sputum AFB microscopy than with STLSs with no such training and working in the field.     

Bidirectional Glenn shunt for right ventricular endomyocardial fibrosis

A 25-year-old man in New York Heart Association functional class IV with right ventricular endomyocardial fibrosis received a palliative bidirectional Glenn shunt. Despite a stormy postoperative convalescence the bidirectional Glenn shunt provided good long-term palliation.