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Biomedical subjects

K S Channer

Publications and source records attributed to K S Channer.

At least 109 records · Page 6Linked to original sources
PubMed1993

Intravenous enoximone or dobutamine for severe heart failure after acute myocardial infarction: a randomized double-blind trial.

Intravenous infusions of enoximone or dobutamine were given, using a double dummy technique, in a randomized, double-blind study, to 18 patients with acute myocardial infarction who had persisting signs of left ventricular failure after treatment with intravenous diuretics. Blood pressure, heart rate and cardiac output, by transcutaneous Doppler aortovelography, were measured and any arrhythmias recorded by Holter monitoring. Eight of the nine enoximone treated patients showed clinical improvement. One patient in the enoximone group failed to respond and subsequently died. Five of the nine dobutamine treated patients showed clinical improvement. The other four patients in the dobutamine group experienced tachyarrhythmias and were withdrawn from the study; one of these patients also deteriorated and died. There were no significant differences in systolic or diastolic blood pressure either within or between the two treatment groups during the study. Enoximone increased cardiac output by 32% (P = 0.003), and dobutamine by 46% (P < 0.001); there was no significant difference between groups. Dobutamine also significantly increased heart rate from a mean of 108 beats.min-1 to 117 beats.min-1 (P < 0.001). There was no difference between the two groups in ventricular ectopic counts, but dobutamine produced significantly more runs of supraventricular and ventricular tachycardia (P = 0.0003). Enoximone was better tolerated with fewer side-effects than dobutamine in doses which produced similar increases in cardiac output. In the setting of an acute myocardial infarction when inotropic therapy is indicated, enoximone is a better choice than dobutamine.

Adult↗
PubMed1993

Subcutaneous versus intravenous administration of heparin in the treatment of deep vein thrombosis; which do patients prefer? A randomized cross-over study.

Patient preference for intravenous or subcutaneous heparin in the treatment of deep venous thrombosis was assessed in a randomized cross-over study. Twenty patients with venographically proven deep venous thrombosis were randomized to receive subcutaneous or intravenous heparin for 3 days followed by 3 days of the other treatment. Discomfort at the injection site, assessed by visual analogue scale, was significantly less for the subcutaneous than the intravenous administration route (P < 0.001), mobility was thought to be better when receiving subcutaneous heparin (P < 0.005) and patients' overall preference was for subcutaneous treatment (P < 0.001).

Adult↗
PubMed1993

Thrombolysis in acute myocardial infarction: an audit of practice.

A retrospective casenote audit of the use of thrombolysis in 212 of 335 patients with acute myocardial infarction (63%) was carried out on the coronary care unit of a Sheffield teaching hospital. The overall inpatient mortality was 17%, 12% in the thrombolysis group and 26% in the remainder (p < 0.005). Patients aged 75 years or older were less likely to die if they received thrombolytics (p < 0.05) despite an excess of anterior myocardial infarctions in the thrombolysis group (p < 0.01). The infusion of streptokinase had to be stopped in five patients (4%) because of allergy or arrhythmias. Thrombolytic therapy was considered in all patients with acute myocardial infarction; it was withheld inappropriately in eight cases and given inappropriately in two. Thrombolysis produced clear benefits in mortality for all patients, including those over 75 years old. There was a high rate of use of thrombolysis which was generally safe and appropriate, although adjustments to the guidelines may allow even more patients to receive this therapy.

Adult↗
PubMed1992

Relative effects of fat-, carbohydrate- and protein-containing liquid diets on cardiac output in healthy adult subjects.

1. Nine healthy adult subjects consumed four types of proprietary liquid diet of similar volume and calorific value but of different nutritional composition. The effects on resting cardiac output, mean blood pressure and pulse rate were measured. 2. A significant rise in cardiac output occurred with the balanced, protein and carbohydrate diets but not with the fat diet. The greatest rise was seen with the balanced diet. Water alone had no effect on cardiac output. 3. The average time taken to reach peak cardiac output was shortest with the carbohydrate diet and longest with the fat diet. 4. The increases in cardiac output resulted from a rise in both pulse rate and stroke volume. The carbohydrate diet produced the most sustained rise in pulse rate but the least sustained elevation in stroke volume. 5. No significant changes were seen in mean blood pressure when each liquid meal was compared with water. 6. Our data show that the increase in cardiac output with liquid ingestion is related to the dietary components. These effects are additive.

Adult↗
PubMed1991

The drug treatment of atrial fibrillation.

1. Atrial fibrillation is an inefficient cardiac rhythm associated with impaired exercise tolerance, exertional dyspnoea, palpitation and a substantial risk of thromboembolism. 2. The first decision in management is to consider cardioversion which can be achieved in suitable cases electrically, or pharmacologically with a class Ic antiarrhythmic drug like flecainide or propafenone. 3. Prophylaxis in paroxysmal atrial fibrillation is best achieved with a class Ic drug or a class III drug such as sotalol or amiodarone. 4. Control of ventricular rate in chronic atrial fibrillation can be achieved by pharmacological manipulation of the atrioventricular node by digoxin alone, or in combination with the calcium channel blockers verapamil or diltiazem, or beta-adrenoceptor blockers with intrinsic sympathomimetic activity like pindolol or xamoterol. 5. In view of the considerable risk of thromboembolism in patients with chronic atrial fibrillation anticoagulation or at least treatment with aspirin should be considered.

Adrenergic beta-Antagonists↗
PubMed1991

Cardioversion of atrial fibrillation of recent onset with flecainide.

Twenty-eight patients with atrial fibrillation of less than 1 month's duration were given a single intravenous bolus of flecainide (2 mg/kg). Nineteen patients (68%) were successfully converted to sinus rhythm. Of the 19 patients with atrial fibrillation of less than 72 hours duration, 18 (95%) were successfully converted. Failure to cardiovert was associated with cardiomegaly on chest X-ray and larger left atrial diameter measured echocardiographically. Of the 9 patients who failed to convert, 2 had biochemical evidence of thyrotoxicosis and chronic obstructive pulmonary disease. Of the 19 patients successfully cardioverted, the atrial fibrillation complicated acute myocardial infarction in 3 cases and a pulmonary embolism in one. Six cases occurred post-operatively and in 3 out of 6 the patient was ventilated. No side effects were observed. The use of intravenous flecainide should avoid the need for electrical DC conversion even in sick patients. Failure of conversion is associated with covert underlying predisposing factors and duration of atrial fibrillation of more than 72 hours.

Adult↗
PubMed1990

The effect of oral dosing of xamoterol on systolic time intervals in man and xamoterol plasma concentrations in heart failure patients.

1. Six healthy male human volunteers of mean age 30.8 years (range 23-37) were given single oral doses of xamoterol (20, 50, 100 or 250 mg) and placebo with a 1 week interval between each dose. Xamoterol produced a significant decrease in systolic time intervals (QS2I, LVETI and PEPI) and a significant increase in systolic blood pressure indicating a positive inotropic effect on the heart at rest. The changes in QS2I were dose-related. Maximum decreases in QS2I were noted 1 to 2 h after dosing and were achieved with a dose of 100 mg. 2. In a second study, oral administration of xamoterol at 3 doses (100, 200 or 300 mg) and placebo were studied in 12 patients of mean age 60.4 years (range 52-73) with mild to moderate heart failure. Each dose was given twice daily for 7 days in a random order. Each dose of xamoterol produced a significant decrease in systolic time intervals indicating a positive inotropic effect on the heart at rest in patients with heart failure. It was not possible to distinguish between the effects of the three doses of xamoterol. 3. In heart failure patients, peak plasma concentrations of xamoterol occurred 1 to 2 h after dosing at all dosage levels and there was a linear relationship between dose and plasma concentration. 4. In both studies xamoterol was well tolerated and only minor adverse experiences were reported. 5. We conclude that, at rest, xamoterol has a positive inotropic effect on the heart when given orally to healthy volunteers or patients with mild to moderate heart failure.

Adult↗
PubMed1989

Myocardial bridging of the coronary arteries.

Of 1102 consecutive coronary angiograms 16 (1.4%) were found to have systolic narrowing typical of myocardial bridging on the left anterior coronary artery or its branches. Four cases of bridging had otherwise normal coronary arteriograms, four were associated with left ventricular hypertrophy (three in cases of aortic valve disease and one case of hypertrophic cardiomyopathy) and eight were found in association with fixed coronary artery stenoses. Bridging was seen more commonly than expected on normal angiograms. When bridging was associated with left ventricular hypertrophy it affected a longer segment and caused more severe compression. When bridging was found in patients with coronary artery disease, it was not associated with atheroma at its site. Evidence for a pathogenic role of myocardial bridging in ischaemic heart disease is discussed.

Adult↗