Cardiovagal autonomic dysfunction in relation to HIV-associated lipodystrophy

PURPOSE

Human immunodeficiency virus (HIV)-associated lipodystrophy (LD) may be mediated by changes in the autonomic nervous system. We examined the autonomic function among HIV-infected patients with LD compared to HIV-infected patients without LD (non-LD) and HIV-negative controls (controls).

METHOD

This cross-sectional study examined cardiovagal autonomic function among the three groups. LD was defined in HIV-infected patients as increased visceral adipose accumulation and peripheral lipoatrophy. Cardiovagal autonomic testing was assessed by measuring heart rate variability during rest, paced breathing, and upright tilt and was analyzed in time and frequency domains.

RESULTS

Cardiovagal testing was performed on 58 participants: 26 controls, 20 non-LD, and 12 LD. After adjustment for visceral fat, time domain analysis showed decreased heart rate variability in patients with LD compared to the other groups (p < .05). The frequency domain analysis showed decreased high-frequency power and increased low- to high-frequency power ratio in the LD group compared to both groups during rest and to non-LD during tilt (p < .05).

CONCLUSION

Patients with LD have altered cardiovagal modulation. Patients with LD had lower heart rate variability and higher sympathetic modulation compared to non-LD and controls. These alterations may be prognostic of increased cardiovascular disease morbidity and mortality.

Prospective Association Between Low and High Total and Low-Density Lipoprotein Cholesterol and Coronary Heart Disease in Elderly Men

OBJECTIVES

To examine the relationship between total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) and the incidence of coronary heart disease (CHD) in elderly men.

DESIGN

Prospective.

SETTING

Population based.

PARTICIPANTS

A sample of 2,424, Japanese-American men aged 71 to 93 was used.

MEASUREMENTS

Six years of data on incident fatal plus nonfatal CHD were examined.

RESULTS

Analysis revealed a significant U-shaped relationship between age-adjusted CHD rates and both TC and LDL-C. The ranges of TC and LDL-C with the lowest risk of CHD were 200 to 219 mg/dL and 120 to 139 mg/dL, respectively. As cholesterol concentrations declined and increased beyond these ranges, the risk of CHD increased. These U-shaped relationships remained significant after adjusting for age and other risk factors.

CONCLUSION

The U-shaped associations between TC and LDL-C and CHD imply a complex relationship between lipids and CHD in late life. The results indicate that elevated lipid levels should continue to be treated in healthy elderly individuals, as they are in those who are younger, although pharmacologically lowering lipids to excessively low levels in the elderly may warrant further study, as does the contribution of subclinical frailty to the relationship of lipids to CHD risk.

Crystal Methamphetamine‐Associated Cardiomyopathy: Tip of the Iceberg?

BACKGROUND

Crystal methamphetamine has become a drug of widespread use. Previous reports describe myocardial infarction, pulmonary edema, and aortic dissection related to methamphetamine use. Cardiomyopathy due to methamphetamine exposure has been rarely described.

METHODS

We identified 1640 patients admitted in a 4-yr period with a primary or secondary diagnosis of cardiomyopathy. We excluded patients with known cause of cardiomyopathy other than substance abuse. We found 120 patients had a diagnosis of substance abuse, including 21 patients with methamphetamine use. We retrospectively reviewed the medical records of these 21 crystal methamphetamine users.

RESULTS

Nineteen (84%) underwent echocardiography with consistent findings of dilated cardiomyopathy and global ventricular dysfunction. Of five who had a nuclear myocardial perfusion study, none had evidence of ischemia or infarct. Of six who underwent cardiac catheterization, only one had evidence of coronary stenosis.

CONCLUSION

Methamphetamine use appears to produce cardiomyopathy in some users. The pathogenesis is probably similar to that of cocaine and catecholamine-induced cardiomyopathy. Cellular, animal, and clinical data support the link between methamphetamine exposure and myocardial pathology.

The American Diabetes Association and World Health Organization classifications for diabetes: their impact on diabetes prevalence and total and cardiovascular disease mortality in elderly Japanese-American men

OBJECTIVE

To compare the prevalence of diabetes according to the American Diabetes Association (ADA) and World Health Organization (WHO) classifications in a sample of elderly Japanese-American men; to examine the association with total and cardiovascular mortality by diabetes status using both classifications; and to determine whether the fasting or 2-h glucose measurement is a stronger predictor of adverse outcomes.

RESEARCH DESIGN AND METHODS

Examinations given from 1991 to 1993 in the Honolulu Heart Program were used as baseline for these analyses. Subjects were 71-93 years of age at that time and were followed for total and cardiovascular disease mortality for up to 7 years.

RESULTS

A total of approximately 66% of individuals who had diabetes by WHO criteria were missed when the ADA definition was used. The relative risks of total and cardiovascular mortality for those with versus those without diabetes were similar for both definitions; however, when fasting and postload glucose measures were analyzed as continuous variables, the 2-h measurement was a superior predictor and was independent of fasting glucose. In contrast, fasting glucose was not an independent predictor of these outcomes in the presence of the 2-h measurement.

CONCLUSIONS

The prevalence of glucose metabolism abnormalities was very high among elderly Japanese-American men. The WHO classification was superior to the ADA classification in identification of subjects at high risk for adverse outcomes. Therefore, we conclude that the 2-h glucose measurement is valuable and should be retained in epidemiologic studies.

Abiotrophia endocarditis: a case report and review of literature

Nutritionally Variant Streptococci (NVS) were first grouped under viridans streptococci, although they differed from the latter by variant growth characteristics. NVS cause approximately 5% of cases of bacterial endocarditis. Infective endocarditis caused by NVS has a higher rate of complications than endocarditis caused by other viridans streptococci. Recently NVS were separated from other viridans streptococci to form a new genus Abiotrophia. Since then, only four case reports have described the clinical course of Abiotrophia endocarditis. Therefore, current knowledge on this disease derives from previous data on NVS endocarditis. We present the case of Abiotrophia endocarditis, followed by discussion of relevant literature.

The plasma membrane-associated protein RS1 decreases transcription of the transporter SGLT1 in confluent LLC-PK1 cells

Previously we cloned RS1, a 67-kDa polypeptide that is associated with the intracellular side of the plasma membrane. Upon co-expression in Xenopus laevis oocytes, human RS1 decreased the concentration of the Na(+)-D-glucose co-transporter hSGLT1 in the plasma membrane (Valentin, M., Kühlkamp, T., Wagner, K., Krohne, G., Arndt, P., Baumgarten, K., Weber, W.-M., Segal, A., Veyhl, M., and Koepsell, H. (2000) Biochim. Biophys. Acta 1468, 367-380). Here, the porcine renal epithelial cell line LLC-PK1 was used to investigate whether porcine RS1 (pRS1) plays a role in transcriptional up-regulation of SGLT1 after confluence and in down-regulation of SGLT1 by high extracellular D-glucose concentrations. Western blots indicated a dramatic decrease of endogenous pRS1 protein at the plasma membrane after confluence but no significant effect of D-glucose. In confluent LLC-PK1 cells overexpressing pRS1, SGLT1 mRNA, protein, and methyl-alpha-D-glucopyranoside uptakes were drastically decreased; however, the reduction of methyl-alpha-D-glucopyranoside uptake after cultivation with 25 mm D-glucose remained. In confluent pRS1 antisense cells, the expression of SGLT1 mRNA and protein was strongly increased, whereas the reduction of SGLT1 expression during cultivation with high D-glucose was not influenced. Nuclear run-on assays showed that the transcription of SGLT1 was 10-fold increased in the pRS1 antisense cells. The data suggest that RS1 participates in transcriptional up-regulation of SGLT1 after confluence but not in down-regulation by D-glucose.

Blood pressure dysregulation syndrome. The case for control throughout the circadian cycle

Blood pressure dysregulation syndrome is characterized by abnormal swings in blood pressure following postural changes, meals, exercise, and during sleep. Although the syndrome may occur in normotensive individuals, a growing body of evidence suggests an association between blood pressure dysregulation and hypertension. Diagnosis can be aided using 24-hour ambulatory blood pressure monitoring. Improved understanding of the syndrome and heightened awareness of its existence in older persons can help clinicians provide more effective management of hypertension. Adequate control of blood pressure throughout the circadian cycle should be a treatment objective.

Observations on recurrent syncope and presyncope in 641 patients

BACKGROUND

Syncope is a common disorder that is potentially disabling and affects both young and old. Once neurological, cardiological, and metabolic causes have been excluded, there remains a group in which diagnosis is unclear; some may have an autonomic basis. We therefore did a retrospective study on consecutive patients referred to our tertiary referral autonomic centres between 1992 and 1998 with recurrent syncope and presyncope, in whom non-autonomic causes, before referral, had been sought and excluded. The object was to find out whether autonomic investigation helped diagnosis.

METHODS

Data from case notes and from the autonomic database on 641 patients were analysed. Syncopal patients with a known or provisional diagnosis of autonomic failure were excluded from analysis. The role of screening tests in establishing or excluding an autonomic cause was assessed. Response to additional autonomic tests (such as head-up tilt with or without venepuncture, and food challenge and exercise) was documented. Some patients underwent further testing if non-autonomic neurological, psychiatric, and other disorders were considered.

FINDINGS

Screening autonomic function tests indicated orthostatic hypotension and confirmed chronic autonomic failure in 31 (4.8%) patients. Neurally mediated syncope was diagnosed in 279 (43.5%) on the basis of clinical features and autonomic testing. Most had vasovagal syncope (227 [35%]); other causes included carotid sinus hypersensitivity (37 [5.8%]), and a group of 15 (2.3%) were associated with rarer causes such as micturition and swallowing. Miscellaneous cardiovascular causes (systemic hypotension, arrhythmias), or drugs, contributed to syncope in 53 (8.3%). Non-autonomic neurological causes included vestibular dysfunction (32 [5%]) and epilepsy (11 [1.7%]). In 56 (8.7%) a psychiatric cause was thought to be contributory. In 179 (27.9%), syncope was of unknown cause.

INTERPRETATION

In recurrent syncope and presyncope, when cardiac, neurological, and metabolic causes have been excluded, autonomic investigation can aid management by making, confirming, or excluding various factors or diagnoses.

Postural hypertension in elderly men--the Honolulu Heart Program

Postural hypertension is a condition in which the blood pressure rises abnormally during standing. The aim of this study is to determine the prevalence of postural hypertension and its association with morbidity and subsequent mortality. At the fourth examination (1991-1993) of the Honolulu Heart Program longitudinal cohort, 3741 Japanese-American men aged 71-93 were examined. Prevalence of postural hypertension in this cohort was 39%. Although there was a high prevalence of postural hypertension in this cohort, its clinical significance is questionable as there were no significant correlations with morbidity and subsequent mortality.

[Consensus on the diagnosis of multi-system atrophy]

We report the results of a consensus conference on the diagnosis of multiple system atrophy. We describe the clinical features of the disease, which include four domains: autonomic failure/urinary dysfunction, parkinsonism and cerebellar ataxia, and corticospinal dysfunction. We set criteria to define the relative importance of these features. The diagnosis of possible multiple system atrophy requires one criterion plus two features from separate domains. The diagnosis of probable multiple system atrophy requires the criterion for autonomic failure/urinary dysfunction plus poor levodopa responsive parkinsonism or cerebellar ataxia. The diagnosis of definite multiple system atrophy requires pathological confirmation.

Consensus statement on the diagnosis of multiple system atrophy

We report the results of a consensus conference on the diagnosis of multiple system atrophy (MSA). We describe the clinical features of the disease, which include four domains: autonomic failure/urinary dysfunction, parkinsonism and cerebellar ataxia, and corticospinal dysfunction. We set criteria to define the relative importance of these features. The diagnosis of possible MSA requires one criterion plus two features from separate other domains. The diagnosis of probable MSA requires the criterion for autonomic failure/urinary dysfunction plus poorly levodopa responsive parkinsonism or cerebellar ataxia. The diagnosis of definite MSA requires pathological confirmation.

Consensus statement on the diagnosis of multiple system atrophy

We report the results of a consensus conference on the diagnosis of multiple system atrophy (MSA). We describe the clinical features of the disease, which include four domains: autonomic failure/urinary dysfunction, parkinsonism and cerebellar ataxia, and corticospinal dysfunction. We set criteria to define the relative importance of these features. The diagnosis of possible MSA requires one criterion plus two features from separate other domains. The diagnosis of probable MSA requires the criterion for autonomic failure/urinary dysfunction plus poorly levodopa responsive parkinsonism or cerebellar ataxia. The diagnosis of definite MSA requires pathological confirmation.

Consensus statement on the diagnosis of multiple system atrophy. American Autonomic Society and American Academy of Neurology

We report the results of a consensus conference on the diagnosis of multiple system atrophy (MSA). We describe the clinical features of the disease, which include four domains: autonomic failure/urinary dysfunction, parkinsonism and cerebellar ataxia, and corticospinal dysfunction. We set criteria to define the relative importance of these features. The diagnosis of possible MSA requires one criterion plus two features from separate domains. The diagnosis of probable MSA requires the criterion for autonomic failure/urinary dysfunction plus poor levodopa responsive parkinsonism or cerebellar ataxia. The diagnosis of definite MSA requires pathological confirmation.

Gunshot wounds in children under 10 years of age. A new epidemic

Before 1980 we had not treated any children with gunshot wounds who were younger than 10 years of age, but the number has increased dramatically each year since then. Thirty-four children younger than 10 years of age were treated for gunshot wounds from 1980 to 1987. Sociologic and epidemiologic data were assessed by a child-abuse team and police. Other studies have concluded that gunshot wounds in young children were usually caused by unintentional injury, child abuse, or neglect. From our present study we add a further, and very disturbing, category, that of attempted or intentional pediatric homicide. The children in this category were shot in retaliation for gang activities of their older siblings. This study demonstrates that the majority of our patients' childhood gunshot wounds were related to gang violence and retaliation, the availability of handguns in the home, and child neglect. The prevalence of childhood gunshot wounds in the inner city is increasing dramatically.

Wolff-Parkinson-White syndrome presenting in atrial fibrillation

A case of atrial fibrillation in a patient with Wolff-Parkinson-White (WPW) syndrome is presented. In this case, the patient's ECG initially was misread as ventricular tachycardia. The therapy was appropriate for the actual condition, although electrical cardioversion and defibrillation eventually were required. The treatment of WPW with atrial fibrillation in this case consisted of lidocaine and procainamide. Verapamil, propranolol, and digoxin, which normally are indicated for WPW with tachyarrhythmias, are contraindicated for WPW with atrial fibrillation.