Comparison at Necropsy of Heart Weight in Women Aged 20 to 29 Years With Fatal Trauma or Chemical Intoxication Versus Fatal Natural Cause (A Search for the Normal Adult Heart Weight).

The present obesity epidemic makes determining the normal heart weight in adults difficult. This study examines the heart weight at autopsy in 104 women aged 20 to 29 years who died in 1978 to 1980 before the overweight epidemic ensued. Of the 104 cases, the hearts weighed ≤300 g in 86 (83%) and >300 g in 18 (17%). Of the 67 cases dying from an unnatural cause (trauma or chemical intoxication), only 3 (4%) had hearts weighing >300 g; of the 37 patients dying from a variety of natural causes, 15 (41%) had hearts weighing >300 g (p <0.001). The body mass index (BMI) was ≤25 kg/m2 in 82 cases (79%) and the hearts in them ranged from 120 to 400 g (mean 262 ± 51; median 257 g); of the 22 cases (21%) in whom the BMI was >25 kg/m2, the hearts ranged from 230 to 850 g (mean 351 ± 142; median 300 g). In conclusion, the cases dying from an unnatural cause had smaller mean heart weights than those women dying from a natural cause and those with a normal BMI (≤25 kg/m2) had smaller mean heart weights than those with a BMI >25 kg/m2. The normal heart weight in young women dying from an unnatural cause with few exceptions is <300 g.

Vascular endothelial growth factor in the cerebrospinal fluid of infants who died of sudden infant death syndrome: evidence for antecedent hypoxia.

OBJECTIVES: Recurrent hypoxemia has been proposed as an important pathophysiological mechanism underlying sudden infant death syndrome (SIDS). However, conflicting results emerged when xanthines were used as markers for hypoxia. The vascular endothelial growth factor (VEGF) gene is highly sensitive to changes in tissue partial oxygen tension, and changes in genomic and protein expression occur even after changes in oxygenation within the physiologic range. METHODS: For determining whether hypoxia precedes SIDS, VEGF levels were measured using an enzyme-linked immunosorbent assay in the cerebrospinal fluid (CSF) of 51 SIDS infants and in 33 additional control infants who died of an identifiable cause. In addition, 6 rats that had a chronically implanted catheter in the lateral ventricle were exposed to a short hypoxic challenge, and VEGF concentrations were measured in CSF at various time points for 24 hours. Another set of 6 rats were killed with a pentobarbital overdose, and VEGF CSF levels were obtained at different time points after death. RESULTS: Mean VEGF concentrations in CSF were 308.2 +/- 299.1 pg/dL in the SIDS group and 85.1 +/- 82.9 pg/dL in those who died of known causes. Mean postmortem delay averaged 22 hours for both groups. In rat experiments, hypoxic exposures induced time-dependent increases in VEGF, peaking at 12 hours and returning to baseline at 24 hours. Postmortem duration in the animals was associated with gradual increases in VEGF that reached significance only at 36 hours. CONCLUSIONS: We conclude that VEGF CSF concentrations are significantly higher in infants who die of SIDS. We postulate that hypoxia is a frequent event that precedes the sudden and unexpected death of these infants.

A comparison of respiratory symptoms and inflammation in sudden infant death syndrome and in accidental or inflicted infant death.

Upper respiratory infection and pulmonary inflammation are common in sudden infant death syndrome, but their role in the cause of death remains controversial. Controlled studies comparing clinical upper respiratory infection and inflammation in sudden infant death syndrome with sudden infant deaths caused by accidents and inflicted injuries (controls) are unavailable. Our aim was to compare respiratory inflammation and upper respiratory infection within 48 hours of death and postmortem culture results in these two groups. A retrospective analysis of upper respiratory infection and pathologic variables in the trachea and lung of 155 infants dying of sudden infant death syndrome and 33 control infants was undertaken. Upper respiratory infection was present in 39% of sudden infant death syndrome cases and 40% of control cases. Upper respiratory infection was more likely to have occurred in association with more severe lymphocytic interstitial pneumonitis when sudden infant death syndrome cases and control cases were combined ( P=.04). Proximal and distal tracheal lymphocytic infiltration was more severe in control cases than in sudden infant death syndrome cases ( P=.01 and.01, respectively). Lymphocytic infiltrations of the bronchi, bronchioles, and pulmonary interstitium were similar between groups. Bronchial associated lymphoid tissue was more prominent in control cases ( P=.04). Cultures were positive in 80% of sudden infant death syndrome cases, 78% of which were polymicrobial. Among control cases, 89% were positive, with 94% being polymicrobial. This study confirms that microscopic inflammatory infiltrates in sudden infant death syndrome are not lethal.

Medial smooth muscle thickness in small pulmonary arteries in sudden infant death syndrome revisited.

Increased relative medial thickness (RMT) of smooth muscle in small pulmonary arteries, peripheral extension of smooth muscle into the alveolar wall arteries, and right ventricular hypertrophy (RVH), in response to purported prolonged hypoxia, have been reported in sudden infant death syndrome (SIDS). Prone sleep position, an important risk factor for SIDS, predisposes infants to hypoxia from airway obstruction or rebreathing. Since publication of the earlier pulmonary artery studies, the SIDS definition has been expanded, and sudden infant death investigational protocols have been implemented. Our aims in this study were to (1) compare RMT in preacinar arteries (PA), intra-acinar arteries accompanying small airways (SIA), and alveolar wall arteries (AW) in SIDS infants and controls; (2) correlate RMT with postmortem variables; (3) determine if peripheral extension occurred more often in SIDS infants than in controls; and (4) determine if RVH occurred in SIDS. Movat-stained sections from standardized tissue blocks taken prospectively from the apex of the right upper lobe from 88 SIDS cases and 17 controls were evaluated using a computer-assisted digitizing system with images obtained from a microscope with an attached video camera. When adjusted for age, the RMT values for the SIA arteries were significantly greater in controls, while the PA and AW arteries were not statistically different between the SIDS cases and controls. Peripheral medial smooth muscle extension did not differ between the groups, and RVH was not seen in SIDS cases. Given the recent identification of brain stem abnormalities interfering with protective cardiorespiratory responses against acute life-threatening hypoxia perhaps precipitated by prone sleeping, our data suggest that SIDS is an acute event not preceded by recurrent or prolonged apnea and hypoxia.