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Biomedical subjects

C Bass

Publications and source records attributed to C Bass.

At least 73 records · Page 4Linked to original sources
PubMed1988

Value of measuring end tidal partial pressure of carbon dioxide as an adjunct to treadmill exercise testing.

The end tidal partial pressure of carbon dioxide (PCO2) was measured during treadmill exercise in 30 normal controls and 113 patients referred for assessment of chest pain. Among the 92 patients without significant ST depression hypocapnia occurred more often in those reporting "typical" than "atypical" chest pain (17 of 22 patients compared with 29 of 70; p less than 0.01). Hypocapnia was uncommon in patients with significant ST depression whether reporting typical or atypical chest pain (one of 10 patients and two of 11, respectively). Hypocapnia at rest (PCO2 less than 4 kPa) occurred in 16 (14%) patients but in only one control. Hypocapnia occurred during or after exercise in only one control and three of the 21 patients with significant ST depression on exercise (group 1). The remaining 92 patients were divided into those with a history suggestive of hyperventilation (group 2; n = 30) and those without (group 3; n = 62). Hypocapnia developed significantly more often in both these groups (21 and 25 patients respectively) than in controls or patients with significant ST depression. An abnormal response of the PCO2 to exercise provided objective data to support a clinical suspicion of chest pain induced by hyperventilation in 24 cases, suggested a cause for equivocal ST depression other than coronary stenosis in five patients, and led to the diagnosis of previously unsuspected respiratory disease in 14 patients. Measurement of end tidal PCO2 gives additional valuable diagnostic information during the conventional treadmill exercise test in patients with both typical and atypical chest pain.

Carbon Dioxide↗
PubMed1988

Panic anxiety and hyperventilation in patients with chest pain: a controlled study.

We studied the relation between mood disorder and hyperventilation (hypocapnia) before and during exercise treadmill testing in 113 chest pain patients attending a cardiac clinic and 30 healthy controls. In most patients end-tidal PCO2 (PCO2) rose in the normal way on exercise but in a subset of 24 (21 per cent) there was no rise: these patients with initial hyperventilation had significantly higher anxiety scores than those with a normal exercise-induced rise in PCO2. Two of the 24 had ischaemic heart disease and 10 (42 per cent) complained of recent panic anxiety compared with 12 (13 per cent) of the 89 with normal rise in PCO2 (p less than 0.05). Rates of psychiatric morbidity were similar in patients with 'typical' and 'atypical' chest pain. Resting hypocapnia occurred more often in patients with panic anxiety than in either anxious or non-anxious patients without panic. Panic patients also reported more symptoms of breathlessness and hyperventilation-related complaints than those without panic. Our findings confirm the important association between panic and hyperventilation in patients with chest pain. Furthermore, patients with exercise-induced hyperventilation are more likely to have a psychiatric than a cardiac disorder. Early detection and treatment of these patients may reduce the potential morbidity associated with unnecessary invasive investigations.

Adult↗
PubMed1987

Does atenolol improve physical and psychological function after coronary artery bypass surgery: a controlled study.

A double-blind prospective randomized trial of atenolol (100 mg once daily) was carried out on 88 patients (78 men) awaiting coronary artery bypass graft surgery. Standardized ratings of both psychiatric morbidity and functional capacity were made before, 3 months (n = 82) and 12 months (n = 81) after surgery. One year after surgery men in the atenolol group had a significantly shorter treadmill exercise time than those on placebo (7.21 +/- 0.28 min vs 8.32 +/- 0.40 min; p less than 0.05), but the frequency of reported anginal attacks during the year was similar in both drug groups. Improvement in functional capacity (measured in exercise time) in the 71 men following surgery was related to both physical and psychological variables assessed before the operation. Men with more severe occlusive disease, lower neuroticism and higher extraversion scores pre-operatively showed greater percentage improvement in exercise time after surgery. Women had significantly levels of psychiatric morbidity and shorter treadmill exercise time than men both before and after surgery. Of the psychiatric and psychological variables, only ratings of Type A behaviour fell significantly in the atenolol group (170.9 +/- 5.3 vs 163.0 +/- 5.2; p less than 0.05). This change, which is probably not clinically important, occurred independently of any reduction in either overall psychiatric morbidity score or ratings of somatic symptoms mediated by beta-adrenergic receptors. The atenolol group reported more side-effects of both psychological and physical symptoms than the placebo group. We do not recommend the routine use of atenolol after bypass graft surgery. Our findings failed to support the suggestion that Type A characteristics may reflect an underlying sympathetic nervous system reactivity.

Angina Pectoris↗
PubMed1987

Physical and psychological correlates of severe heart disease in men.

Seventy eight men were assessed one month before coronary artery bypass graft surgery using standardized measures of psychiatric morbidity and personality as well as a measure of emotional expression (the CECS). All patients had at least one coronary vessel occluded by 75% or more of its diameter, and functional capacity was assessed by calculating the exercise treadmill time (in seconds) for each patient. Most of the variance in exercise treadmill time was accounted for by the following variables: young age, short duration of symptoms, and less severe angina. Only one of five men was designated a psychiatric 'case'. The only psychological measure significantly associated with atherosclerosis was expression of fear (on the CECS). A measure of Type A behaviour (Bortner score) was related to exercise treadmill time, but not to any of the angiographic or clinical indices of coronary heart disease (CHD). Like other measures of Type A behaviour, the Bortner scale is psychometrically impure and has doubtful validity. More valid behavioural variables (such as those measured by the CECS) require further investigation. Future studies on the relation between psychological factors and the extent of CHD should take account of not only sex differences but also patients without significant CHD: high rates of psychiatric morbidity in such patients confound the relation between psychological trait measures and atherosclerosis.

Adult↗
PubMed1986

Controlled study of respiratory responses during prolonged measurement in patients with chronic hyperventilation.

The respiratory responses of 17 patients with chronic hyperventilation but without demonstrable organic disease (group H) to various manoeuvres were compared with those of 21 healthy controls (group C). The responses were tested according to a 60 min protocol in which periods of rest were replaced by exercise, voluntary hyperventilation (VHV), reading, and CO2 inhalation. 5 patients with severe resting hypocapnia were investigated overnight during sleep. Chronic hyperventilation was of two types--persistent or provoked by exercise or VHV. It was due to modest increases in tidal volume and respiratory frequency but was generally not conspicuous. End-tidal PCO2 levels were gradually corrected to near normal during sleep but not by inhalation of CO2.

Adult↗
PubMed1986

Psychosocial problems following coronary artery bypass surgery.

Most patients undergoing bypass graft surgery derive psychological and social benefits from it. Those who fare badly are likely to have evidence of psychological maladjustments before surgery and to suffer forced retirement (for whatever reason) after it. A sizeable minority develop CNS complications. More prospective controlled studies are needed to determine whether these lead to long-term neuropsychological impairment.

Body Weight↗
PubMed1985

Factitious plumbism.

Explore the source record for details and available documents.

Factitious Disorders↗
PubMed1985

Respiratory and psychiatric abnormalities in chronic symptomatic hyperventilation.

Many physicians believe that the hyperventilation syndrome is invariably associated with anxiety or undiagnosed organic disease such as asthma and pulmonary embolus, or both. Twenty one patients referred by specialist physicians with unexplained somatic symptoms and unequivocal chronic hypocapnia (resting end tidal Pco2 less than or equal to 4 kPa (30 mm Hg) on repeated occasions during prolonged measurement) were investigated. All but one complained of inability to take a satisfying breath. Standard lung function test results and chest radiographs were normal in all patients, but histamine challenge showed bronchial hyper-reactivity in two of 20 patients tested, and skin tests to common allergens were positive in three of 18. Ventilation-perfusion scanning was abnormal in a further three of 15 patients studied, with unmatched perfusion defects in two and isolated ventilation defects in one. None of the 21 had thyrotoxicosis, severe coronary heart disease, or other relevant cardiovascular abnormalities. Ten of the 21 patients were neurotic and suffered from chronic psychiatric disturbance characterised by anxiety, panic, and phobic symptoms. The remainder had no detectable psychiatric disorders but reported proportionately more somatic than anxiety symptoms. Severe hyperventilation can occur in the absence of formal psychiatric or detectable respiratory or other organic abnormalities. Asthma and pulmonary embolus must be specifically excluded.

Adult↗
PubMed1984

Type A behaviour in patients with chest pain: test-retest reliability and psychometric correlates of Bortner scale.

Ninety-nine patients with chest pain and a presumptive diagnosis of coronary heart disease were assessed within 24 hr of angiography using a standardised psychiatric interview, personality inventory and Bortner Type A questionnaire. Ninety-six of the 99 patients completed the Bortner scale 4 months later, when test-retest reliabilities were 0.84 for both the 65 men and 31 women. There were significant correlations between Bortner score and measures of both psychiatric morbidity and neuroticism in men; and those items on the Bortner scale denoting speed and impatience were most highly correlated with neuroticism. None of these associations were noted in women. Men with normal or near-normal coronary arteries had higher measures of extraversion, neuroticism and Type A score than those with important occlusions, suggesting an association between insignificant coronary artery disease, "complaint behaviour" and raised Type A score. The findings question the unitary nature of Type A behaviour, and suggest an important association between the behaviour pattern and the personality dimension of neuroticism in men.

Angina Pectoris↗