Prognostic value of exercise EKG testing in asymptomatic normotensive subjects. A prospective matched study

We prospectively studied 135 asymptomatic normotensive subjects with exercise-induced ST ischemic depression of 1 mm or more and compared them with 379 controls. At least two controls with negative responses on the exercise electrocardiographic (EKG) test were selected for each case and were matched for age, sex, work, community, and coronary-risk-factors index. The end points considered were the following coronary events: angina pectoris, myocardial infarction, and sudden death. After a median follow-up period of 6.0 years for the cases and 6.4 years for the controls, the relative risk was 5.55 (95 per cent confidence limits, 2.75 to 11.22). Coronary events occurred significantly earlier in the cases than in the controls. Our data also suggest that the exercise EKG response is a particularly good prognostic indicator for myocardial infarction. In addition, our analysis has confirmed the predictive roles of age, smoking, blood pressure, and the coronary-risk-factors index and suggests that the exercise EKG response is an additional independent risk indicator for coronary events.

Comparison of mediastinal width, mediastinal-thoracic and -cardiac ratios, and "mediastinal widening" in detection of traumatic aortic rupture

This study was undertaken to determine whether direct measurement of mediastinal width or computation of ratios of measurements of easily detectable mediastinal structures is more effective than the subjective impression of "mediastinal widening" in selecting trauma patients for aortography. A group of five surgeons and radiologists individually read in blinded fashion 149 chest films of trauma victims who had undergone aortography to rule out traumatic rupture of the aorta (TRA). Each made a subjective interpretation of "mediastinal widening," as well as direct measurement of mediastinal width (MW), thoracic width at the level of the mediastinum, cardiac width, and maximum thoracic width. Mediastinal-cardiac (MC), mediastinal-thoracic (MT), and mediastinal-mediastinothoracic (MMT) ratios were calculated. Statistically significant differences were found in all parameters of direct measurement between cases with and without TRA (P from .0001 for MT to .01 for MMT). The critical measurement for mediastinal width separating positive from negative cases was 8.0 cm; the critical ratios were MT = 0.275, MC = 0.555, and MMT = 0.36. Application of these parameters to detect TRA yielded sensitivities of .75 for MW, .68 for MC, .66 for MMT, and .62 for MT. Statistically significant differences between observers' measurements were seen. None of these measurements was as effective as subjective interpretation of mediastinal widening, which had a sensitivity of .91 (P = .0000). We conclude that the subjective impression of mediastinal widening is superior to "objective" direct measurement of mediastinal structures for identification of trauma patients with aortic rupture.

Assessment of mediastinal widening associated with traumatic rupture of the aorta

In order to best determine the reliability and usefulness of widening of the mediastinum (WMED) and other radiographic abnormalities in the selection of trauma patients for aortography to detect traumatic rupture of the aorta (TRA), we designed a blind study in which a panel of radiologists and surgeons reviewed 149 chest films of trauma victims who subsequently underwent aortography to rule out TRA. Sixteen patients had TRA. Panelists identified mediastinal widening (WMED) in 83 of 93 observations on films in cases of TRA (89%). There was a significant association between WMED and TRA found both for the panel as a whole and for each panelist individually (p = 0.0000), making this an extremely reliable sign both in terms of detectability and in signalling the need for aortography. Significant associations with TRA were also found overall for six other radiographic abnormalities but none of these was reliable for all panelists or was as sensitive as WMED in the detection of TRA. Despite the reliability of these signs, panelists making decisions based on the chest film alone failed to recommend aortography in seven of 93 instances of TRA. Direct mediastinal measurements varied by at least 2 cm among panelists in one half of the cases of TRA, and 25% of these (4/16) had at least two measurements of mediastinal width of 7 cm or less. Of all the radiographic signs associated with TRA, widening of the mediastinum is the most reliable, but in this study all observers would not have detected all cases of ruptured aorta using radiographic signs alone. Clinical judgment and consideration of the forces involved in the injury must continue to play an important role in the selection of patients for aortography.

[Electro-vectorcardiographic study in Duchenne de Boulogne progressive muscular dystrophy]

Electrocardiographic changes are well known in Duchenne's muscular dystrophy (DMD). Their cause is still controversial. The aim of this study was: to verify the genetic theory of these changes to improve our understanding of their pathogenesis, by studying the distribution and characteristics of the mother carriers; to determine whether electro-vectocardiography could be of value in detecting carriers of the disease. Fourteen patients aged from 7 to 17 years old with DMD underwent ECG and VCG. ECG changes were recorded in 13 of the 14 cases: increased amplitude of the R wave in the right precordial leads or deep Q waves (amplitude greater than or equal to 2 mm, duration less than 0,04 msec) in the peripheral or left precordial leads. The algebraic sum of R--S in V1 was greater than normal in 6 carriers. VCG criteria of posterior myocardial infarction were fulfilled in 11 patients. "Bites" were recorded in 4 patients and 8 carriers. Electrical changes were therefore found in both patients and carriers with equal significance: in the first group the main appearances were of pseudo-infarction, principally involving the posterior wall; in the second group, less specific changes, best recorded on VCG, suggesting foci of myocardial fibrosis were observed. We think that the "bites" recorded in 66 p. 100 of mothers, could be a useful parameter for detecting carrier subjects.

[Evaluation of systolic intervals in Duchenne cardiomyopathy]

Patients with progressive muscular dystrophy rarely survive beyond the second or third decades: the commonest causes of death are respiratory failure and cardiac failure. An easily repeatable method for early recognition of cardiac dysfunction and its follow-up would therefore be valuable. We performed a polycardiographic study of systolic time intervals in 11 patients with dystrophy (each subject representing an age from 7 to 17 years) in a group comprising 10 of their mothers and in control groups matched for age and sex. The mean values of QS2, PEP and QS1 were significantly higher in patients compared to controls (QS2 : 543 +/- 26 msec compared to 519 +/- 19 msec; PEP : 142 +/- 21 msec compared to 123 +/- 18 msec, and QS1 : 105 +/- 22 msec compared to 75 +/- 12 msec) whilst mean ICT was shorter (36 +/- 11 msec, compared to 49 +/- 5 msec). Mean LVET was comparable in patients and control. These results indicate a reduction in compliance and an increase in end diastolic left ventricular tension. When the systolic time intervals were analysed in each child, an increase in PEP and reduction in LVET were characteristic of the more serious phases of the disease with cardiac failure. It is emphasized that early stages of the disease are characterised by restrictive changes resulting in a reduction in ICT whilst terminal stages with reduced cardiac output cause a reduction in LVET and an increase in PEP. No significant changes were found in the mothers of patients compared to the control group. These results indicate that systolic time intervals may be useful in following up patients with Duchenne's cardiomyopathy.

Mass carbon monoxide poisoning: clinical effects and results of treatment in 184 victims

An epidemiologic and clinical investigation of 184 persons exposed to toxic levels of carbon monoxide (CO) in a public high school has been carried out. Exposure to 500 ppm of CO for periods up to 150 minutes resulted in carboxyhemoglobin (COHb)levels as high as 30% and symptomatic illness in 87% of persons exposed before the possibility of mass CO poisoning was recognized. Severity of symptoms was a reliable basis for triage of victims for immediate hospital treatment, and correlated both with duration of exposure and the length of time it took for victims to feel normal. Therapy consisting of oxygen delivered by mask achieved a half-life for COHb of 137 minutes in hospital-treated patients (compared to 320 minutes with no treatment), but did not fully reverse the symptoms of CO toxicity.

Abdominal aortic aneurysm rupture: statistical analysis of factors affecting outcome of surgical treatment

One hundred sixteen patients underwent surgery for ruptured abdominal aortic aneurysms with intraoperative and overall mortality rates of 20.7% and 51.7%, respectively. The correlation of multiple factors to morbidity and mortality was assessed with detailed statistical analysis. Eight preoperative factors were identified as predictors of mortality. Increased intraoperative mortality rates were associated with heart disease (29%), hypertension (30%), flank ecchymoses (57%), and pulsatile abdominal mass (24%). Increased intraoperative and overall mortality rates were associated with preoperative hypotension (39%, 78%) and BUN levels higher than 30 mg/dl (47%, 82%). Increased overall mortality rates were associated with creatinine levels higher than 3 mg/dl (71%) and a hematocrit of 30.0 to 32.5 vol% (75%) (P less than 0.05). Seven intraoperative factors were identified as predictors of mortality. Increased postoperative mortality rates were associated with a duration of operation of more than 400 minutes (100%), hypotension lasting longer than 110 minutes (88%), estimated blood loss more than 11,000 ml (75%), blood transfusion more than 17 U (68%), fluid administration in excess of 7000 ml (70%), and a blood pressure lower than 100 mm Hg at the conclusion of the operation (88%). Cardiac arrest was associated with increased intraoperative and overall mortality rates (77%, 82%) (P less than 0.05). In general these factors cannot be controlled by the surgeon, and future significant reduction in the operative mortality rate may be possible. These findings support the general concept of aggressive elective resection of abdominal aortic aneurysms.

Comparison of media and culture techniques for detection of Streptococcus pneumoniae in respiratory secretions

We compared the relative efficacy of three methods for the isolation of Streptococcus pneumoniae in lower respiratory secretions. Based on results from 294 clinical specimens, we found that S. pneumoniae was isolated at a frequency of 65% with 5% sheep blood agar or 5% sheep blood agar containing 5 micrograms of gentamicin per ml, both incubated in 5% CO2. Anaerobic incubation of 5% sheep blood agar enhanced the recovery rate of S. pneumoniae to 93%. The improved efficacy with anaerobic incubation is due to the greater ease of recognition of the larger and more mucoid colonies of S. pneumoniae, and to the suppression of the growth of other oral bacteria present in the respiratory sections.

The deficiency of soluble proteins and plastid ribosomal RNA in the albino pollen plantlets of rice

The components of soluble protein and ribosomal RNA in green and albino pollen plantlets of rice were studied by means of polyacrylamide gel electrophoresis. The results were as follows: (1) Soluble protein: the soluble proteins in green pollen plantlets may be fractionated into 15 bands of varying intensities in which the highest content and the most prominent one is band 3 (fraction I protein). Band 3, however, is nearly absent in albino pollen plantlets. (2) Ribosomal RNA (rRNA): rRNA of high molecular weight in green pollen plantlets may be fractionated into 4 bands, i.e. 25S RNA and 18S RNA in cytoplasmic ribosomes, and 23S RNA and 16S RNA in plastid ribosomes. Little or no 23S RNA and 16S RNA, however, is found in albino pollen plantlets. Together with the evidence obtained by other workers, it is suggested that albino forms of pollen plantlets is caused by the impairment of DNA.