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Biomedical subjects

T Crake

Publications and source records attributed to T Crake.

65 records · Page 4Linked to original sources
PubMed1987

Medical treatment of patients with severe exertional and rest angina: double blind comparison of beta blocker, calcium antagonist, and nitrate.

The role of medical treatment of patients who had resting nocturnal angina as well as exertional angina was investigate. The effects of atenolol 100 mg a day, nifedipine 20 mg three times a day, and isosorbide mononitrate 40 mg twice a day were investigated in a double blind, triple dummy randomised study. Nine patients with coronary artery disease, early positive exercise tests, and transient daytime and nocturnal ambulatory ST segment changes were initially assessed off all antianginal medication. They were then treated with each drug for three five day periods. Angina diaries were reviewed and maximal treadmill exercise tests and 48 hour ambulatory ST segment monitoring were performed at the end of each treatment period. Resting and exercise heart rate and blood pressure were significantly lower on atenolol than on either isosorbide mononitrate or nifedipine. The duration of exercise to 1 mm ST segment depression was significantly greater on atenolol than on isosorbide mononitrate. Only one patient had an improvement in exercise tolerance on nifedipine that was greater than the improvement on atenolol; this patient had single vessel disease. The total number and duration of episodes of ST segment change during ambulatory monitoring were significantly lower with atenolol than on either isosorbide mononitrate or nifedipine. Nocturnal ST segment changes were abolished in six patients on atenolol, in six patients on nifedipine, and in five patients on isosorbide mononitrate. When nocturnal ST segment changes occurred, their frequency was reduced with all three drugs. Pain was abolished in four patients on atenolol and pain relief was significantly better on atenolol than on isosorbide mononitrate. There was no significant difference in pain relief between isosorbide mononitrate and nifedipine. Thus beta receptor blockade with atenolol was the most effective means of reducing myocardial ischaemia both during exercise and at rest at night without causing deterioration in any patient. Nocturnal myocardial ischaemia in patients with severe coronary artery disease can be effectively treated with beta receptor antagonists and vasodilators.

Aged↗
PubMed1987

Coronary sinus pH during percutaneous transluminal coronary angioplasty: early development of acidosis during myocardial ischaemia in man.

Coronary sinus pH was measured continuously in eight patients undergoing angioplasty to the left anterior descending coronary artery. A catheter tip pH sensitive electrode with a response time of less than 300 ms and an output of greater than or equal to 57 mV/pH unit was placed high in the coronary sinus. Recordings were obtained during a total of 24 balloon occlusions of the left anterior descending coronary artery varying in duration from 5 to 45 s. Continuous 12 lead surface electrocardiograms were recorded. During or after balloon inflation of greater than or equal to 12 s (n = 4) there was no change in coronary sinus pH or the electrocardiogram. During balloon inflation of greater than or equal to 15 s (n = 20) coronary sinus pH was unaltered but between 4 and 6 s after balloon deflation coronary sinus pH fell transiently by between 0.010 and 0.120 pH units before returning to the control value within 65 s. Ischaemic changes were seen on the electrocardiogram during 15 balloon occlusions. In individual patients the peak fall in coronary sinus pH was related to the duration of occlusion of the left anterior descending coronary artery. A rise in coronary sinus pH (alkalosis) was never seen. In man acidosis occurs in the myocardium after short periods (greater than or equal to 12 s) of ischaemia. The fall of pH precedes ischaemic changes on the surface electrocardiogram and occurs concurrently with the earliest reported changes in contractile function.

Acidosis↗
PubMed1987

Treatment of angina pectoris with nifedipine: a double blind comparison of nifedipine and slow-release nifedipine alone and in combination with atenolol.

The relative efficacy of nifedipine and slow-release nifedipine (Adalat Retard) in the treatment of stable exertional angina pectoris was evaluated in a double blind randomised crossover study in eight patients on no concomitant antianginal treatment and in 10 patients who were additionally on atenolol. Patients were assessed by angina diaries and exercise testing. Slow-release nifedipine was as effective as nifedipine in the treatment of these patients, both alone and in combination with atenolol.

Angina Pectoris↗
PubMed1986

Six minute walking test for assessing exercise capacity in chronic heart failure.

Twenty six patients, mean age 58 years (range 36-68), with stable chronic heart failure, New York Heart Association class II-III, and 10 normal subjects of a similar age range were studied. Exercise capacity was assessed by determining oxygen consumption reached during a maximal treadmill exercise test and by measuring the distance each patient walked in six minutes. There were significant differences in the distance walked in six minutes between normal subjects, patients with heart failure, class II, and those with class III heart failure (683 m, 558 m, and 402 m, respectively (p less than 0.003)). The relation between maximal oxygen consumption and the distance walked in six minutes was curvilinear; thus the distance walked varied considerably in those with a low maximal oxygen consumption but varied little in patients and normal subjects with a high maximal oxygen consumption. All subjects preferred performing the six minute walking test to the treadmill exercise test, considering it to be more closely related to their daily physical activity. The six minute test is a simple objective guide to disability in patients with chronic heart failure and could be of particular value in assessing patients with severe heart failure but less useful in assessing patients with mild heart failure.

Adult↗
PubMed1986

Importance of "reciprocal" electrocardiographic changes during occlusion of left anterior descending coronary artery. Studies during percutaneous transluminal coronary angioplasty.

ST-segment depression remote from the region of acute myocardial infarction was investigated in three groups of patients undergoing left anterior descending coronary angioplasty. Ten patients had single-vessel disease, nine concomitant stenoses in one or more other major coronary arteries, and two myocardial infarction after occlusion during angioplasty. Continuous surface electrocardiograms were recorded from leads I, II, III, v2, and v5, before, during, and after coronary angioplasty and ST-segment changes were measured to 0.1 mm. All ten patients with single-vessel disease had ST-segment elevation in lead v2 and nine also had changes in lead III. All nine patients with multivessel disease had ST-segment changes in lead v2; eight of them had concomitant changes in lead III. Both patients with myocardial infarction had elevation in lead v2 and depression in lead III. ST-segment changes began simultaneously in all leads where they occurred. Most (70%) patients with single-vessel disease who had inferior ST-segment depression had a right-dominant coronary circulation. Therefore, the presence of inferior ST-segment depression during left anterior descending coronary artery occlusion does not indicate the presence or absence of multivessel disease. Furthermore, it is unlikely that this change always represents ischaemia remote from the site of infarction; it is merely an electrical phenomenon.

Aged↗
PubMed1986

The incidence and morphology of ischaemic ventricular tachycardia.

Ventricular arrhythmias are a frequent cause of sudden death in patients with coronary artery disease. The incidence and relationship of ventricular tachycardia to periods of myocardial ischaemia in these patients has not been fully investigated. Ambulatory ST-segment monitoring was performed in 100 consecutive patients with chest pain, of whom 74 had significant coronary artery disease. Recordings were analysed for ST-segment changes and episodes of ventricular tachycardia (greater than 3 beats, rate greater than 100 beats min-1). None of the 26 patients with normal coronary arteries, one of the 22 patients (4.5%) with single vessel disease, one of the 22 patients (4.5%) with double vessel disease and four of the 30 patients (13%) with triple vessel disease, had episodes of non-sustained ventricular tachycardia. Four of these six patients had episodes of reversible ST-segment change but ventricular tachycardia was related to these episodes in only two patients. These two patients had multiple episodes of tachycardia which occurred after the onset of ST-segment change and terminated before the ST-segment returned to baseline; they occurred in clusters with a mean of 12 episodes in each cluster. ST-segment change did not follow episodes of ventricular tachycardia in any patient. The number of ventricular complexes in each episode varied between three and 24 beats and were uniform in three of the six patients. The mean heart rate before the onset of tachycardia was 79 +/- 8 beats per minute and the rate of tachycardia had a mean of 170 +/- 34 beats a minute. Less than 10% of the episodes had a prematurity index of less than 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1986

Value of the bipolar lead CM5 in electrocardiography.

Only bipolar lead recording are available during ambulatory monitoring. Their sensitivity in detecting ST segment changes in relation to standard electrocardiographic leads is not known. The magnitude and direction of ST segment changes in the bipolar lead CM5 were compared with those in standard electrocardiographic leads in patients during exercise testing and percutaneous transluminal coronary angioplasty. Thirty patients with coronary artery disease were studied during exercise tests in which ST segment depression (greater than 0.5 mm) occurred in one or more standard electrocardiographic leads and 13 patients were studied during angioplasty that resulted in ST segment change in one or more leads (I, II, III, V2, V5, and CM5). Lead CM5 was the most sensitive lead (93%) during exercise testing and also showed the greatest magnitude of ST segment change below the isoelectric line in 93% of the patients. Only two patients, one with ST segment elevation in inferior leads and one with changes restricted to septal leads, had no ST segment depression in lead CM5. When ST segment shift from the baseline electrocardiogram was measured the magnitude of depression was greatest in lead CM5 in only 63% of the patients. During angioplasty of the left anterior descending coronary artery, lead CM5 showed ST segment depression in seven patients, ST segment elevation in two, and a biphasic response in one. Two of the three patients with balloon inflation in right coronary artery developed ST segment elevation in lead CM5. Thus lead CM5 is a reliable lead for detecting subendocardial ischaemia experienced during everyday activities in anginal patients. During total occlusion of coronary arteries (as in variant angina or myocardial infarction) lead CM5 commonly shows ST segment depression and changes due to right coronary artery occlusion may not be detected.

Coronary Disease↗
PubMed1985

Gallium scanning by conventional imaging and emission computed tomography in the pretreatment evaluation of lung cancer.

Gallium 67 citrate was evaluated with conventional scanning and emission computed tomography (CT) scanning as a method of pretreatment staging of the intrathoracic, especially mediastinal, spread of lung cancer. Of 31 patients with tumours of various histological types, the isotope was concentrated in the primary lesion in all but one. In 10 out of 12 patients who underwent surgical exploration conventional gallium scanning correctly indicated the mediastinum to be clear and identified two other patients with a tumour of the mediastinum not recognised by chest radiography or emission CT gallium scanning. Neither conventional nor emission CT gallium scanning produced false positive images. Conventional gallium scanning can give information about the mediastinum not available from chest radiographs or bronchoscopy.

Gallium Radioisotopes↗
PubMed1984

Effect of intraluminal hydrocortisone on solute and water absorption in the human jejunum.

To compare the effects of intravenous and intraluminal hydrocortisone on jejunal transport, the proximal jejunum was perfused with glucose (28 mmol/l) in saline in two groups of normal subjects. In the first group of seven subjects, compared with the control period results there were no changes in sodium, water and glucose absorption during the intravenous administration of hydrocortisone. In contrast, intraluminal hydrocortisone (100 mg/l) increased sodium, water and glucose absorption by 169%, 223% and 81% respectively (P less than 0.001 in each case) above the control values, when peripheral plasma cortisol levels were similar to those achieved with intravenous hydrocortisone. In the second group of three subjects, intraluminal hydrocortisone (10 mg/l and 30 mg/l), followed by an intravenous infusion of hydrocortisone, had no effects on sodium, water and glucose absorption. In a third group of six normal subjects perfused with fructose (28 mmol/l) in saline and bicarbonate (28 mmol/l) in saline intraluminal hydrocortisone (100 mg/l) had no effect on solute and water absorption. These results suggest that intraluminal hydrocortisone stimulates glucose-coupled sodium transport by exerting a topical effect on the apical membrane of the jejunal mucosa.

Adult↗
PubMed1983

Constrictive pericarditis and intestinal haemorrhage due to Whipple's disease.

Two months after a pericardectomy for constrictive pericarditis a 37-year-old man presented with diarrhoea, abdominal pain and weight loss. During the course of investigation he developed brisk rectal bleeding and emergency angiography revealed a bleeding site related to an area of abnormal vasculature in the caecum. At laparotomy, the small bowel was found to be inflamed and the mesenteric lymph nodes enlarged. The overall histological appearances, confirmed later on endoscopic duodenal biopsies, were those of Whipple's disease. His symptoms resolved promptly after starting tetracycline therapy. The clinical features of Whipple's disease are protean and often bizarre. We report here a case where the diagnosis was made after the onset of profuse rectal bleeding.

Adult↗