[Atrial flutter with paroxysmal 1:1 atrioventricular conduction]. / Atrieflagren med paroksystisk 1:1 atrioventrikulaer overledning.

Three patients with "lone" paroxysmal atrial flutter complicated by paroxysms of 1:1 AV conduction are presented. One patient (42 years of age) had been misdiagnosed as an neurotic for 18 years. The mechanism, diagnosis and treatment of the condition are outlined. The most characteristic symptoms are dizzy spells and fainting. The recommended diagnostic procedures include long term ECG recording by telemetry or Holter, exercise-ECG and oesophageal-ECG.

Respiratory tract distribution and bioavailability of spiramycin in calves.

Pharmacokinetic determinants of spiramycin and its distribution into the respiratory tract were studied in 2 groups of calves, 4 to 10 weeks old. Group-A calves (n = 4) were used to determine pharmacokinetic variables of spiramycin after IV (15 and 30 mg/kg of body weight) and oral administrations of the drug (30 mg/kg) and to measure distribution of spiramycin into nasal and bronchial secretions. Group-B calves (n = 4) were used to determine distribution of spiramycin into lung tissue and bronchial mucosa. Spiramycin disposition was best described by use of an open 3-compartment model. Mean (+/- SD) elimination half-life was 28.7 +/- 12.3 hours, and steady-state volume of distribution was 23.5 +/- 6.0 L/kg. Bio-availability after oral administration was 4 +/- 3%. High and persistent concentrations of spiramycin were achieved in the respiratory tract tissues and fluids. Tissue-to-plasma concentration ratio was 58 for lung tissue and 18 for bronchial mucosa at 3 hours after spiramycin administration and 137 and 49, respectively at 24 hours. Secretion-to-plasma concentration ratio was 4 for nasal secretions and 7 for bronchial secretions, and remained almost constant with time. Thus, spiramycin penetrates well into the respiratory tract, although the value in bronchial secretions is lower than that in lung tissues and bronchial mucosa. Calculations indicate that a loading dose of 45 mg/kg, administered IV, followed by a maintenance dose of 20 mg/kg, IV, once daily is required to maintain active concentrations of spiramycin against bovine pathogens in bronchial secretions.

[Coronary arteriography after acute myocardial infarction]. / Koronararteriografi efter akut myokardieinfarkt.

On the basis of a population of 1,848 patients with acute myocardial infarction (AMI), prognostic stratification has been developed for detection of patients with high risks of death and repeated AMI in the first year after admission for coronary arteriography (KA). Patients with ischaemia at rest during hospitalization (17% of the patients, 18% one-year mortality), with previous AMI and cardiac failure during hospitalization (8%, 25% mortality), with positive exercise ECG (6%, 11% mortality) and patients with left ventricular ejection fraction (LVEF) between 0.22 and 0.44 (12%, 12% mortality) are recommended for coronary arteriography. Patients over the age of 75 years (31% mortality), patients with very low LVEF (less than 0.20) (33% mortality), patients with negative exercise ECG (3% mortality) and patients with normal LVEF (greater than 0.45) (5% mortality) are not recommended for investigation by coronary arteriography. These guidelines for coronary arteriography after AMI, based on recommendations from abroad should be considered in Denmark in relation to the capacity for carrying out this examination.

Echocardiography and cerebral computed tomography in chronic atrial fibrillation.

Chronic atrial fibrillation (CAF) may be complicated by asymptomatic small silent cerebral infarctions as well as by stroke. The echocardiographic findings in 29 patients with CAF and 29 controls in sinus rhythm are presented. The cerebral computed tomography (CT) findings in these patients were previously published and significantly more small low-density lesions, probably reflecting previous infarctions, were found in patients with CAF than in controls. The aim of the present study was to evaluate if patients with such cerebral lesions had characteristic echocardiographic abnormalities with special reference to patients with CAF. No significant differences could be detected between the groups with and without cerebral lesions regarding the occurrence of valvular heart disease, left ventricular dysfunction, end-diastolic diameter of the left ventricle, left atrial dimension and left ventricular fractional shortening. Only seven patients with CAF (24%) compared with 21 in sinus rhythm (72%) had normal echocardiograms (P less than 0.001). In conclusion, echocardiography gave no guidance to why some patients developed cerebral low-density areas on CT.

[Treatment of acute myocardial infarction--an elucidative report]. / Behandling af akut myokardieinfarkt--en klaringsrapport.

The present-day optimal treatment of patients with acute myocardial infarction (AMI) is reviewed. The prehospital phase should be as brief as possible. Emergency observation and treatment in hospital should be initiated without delay. Schematic stages for mobilization have been discarded and free mobilization is recommended. Routine acute intervention with thrombolysis is recommended for patients in whom symptoms have been present for 6-12 hours and treatment with Aspirin is recommended. Beta-blocking agents are recommended for patients with increased risk after discharge. Treatment of ventricular and supraventricular arrhythmias, block and cardiac failure are reviewed in detail. Patients without complications should be monitored for three to five days and may be discharged after seven to ten days. Exercise ECG should be carried out at discharge to assess the working capacity, ischaemia and subjective reaction. The importance of good patient information is emphasized. Cessation of smoking, control of lipids and blood pressure are important as secondary interventions. As far as possible, outpatient control should be offered after discharge. The criteria for referral to specialized cardiological departments are established both for emergency and elective referral. Patients under the age of 70 years with high risk for repeated AMI or death after discharge (with residual ischaemia) should possibly be referred for coronary arteriography.

Cerebral computed tomography in paroxysmal atrial fibrillation.

Atrial fibrillation (AF) is associated with an increased risk of stroke. In patients with chronic AF, without clinically known cerebrovascular disease, computed tomography (CT) has revealed a high frequency of abnormal low-density areas suggesting old asymptomatic infarcts. To investigate the frequency of such lesions in paroxysmal AF, 30 patients with paroxysmal AF and 30 controls matched in sinus rhythm, without history of cerebrovascular disease, were CT scanned. Four patients with paroxysmal AF (13%) and 3 controls (10%) had abnormal CT scans with areas of low density with sharp demarcation from surrounding tissue. The abnormal areas probably reflected small, clinically silent infarcts. There were no differences between paroxysmal AF and controls in number and size of abnormal areas with apparent tissue loss. In contrast to chronic AF, the risk of such lesions in paroxysmal AF does not seem to be increased compared with matched sinus rhythm controls. This is in agreement with the clinical experience of a low risk of stroke in paroxysmal AF.

Cardiac complications of intravenous digital subtraction angiography.

In a prospective study of 103 patients the incidence of cardiac events during intravenous digital subtraction angiography (i. v. DSA) was investigated. Of 103 patients 17 had known ischaemic heart disease. The examination was performed with an ionic contrast medium, Urografin 76% (sodium megluminediatrizoate), administered by bolus injection into the right atrium. Patients with severe cardiac disease were examined only if the procedure was considered of vital importance. Cardiac events were defined as ST-segment changes of more than 0.1 mV, changes in heart rate of more than 20%, arrhythmias and such symptoms as chest pain and dyspnoea. Ischaemic ST-segment changes during i. v. DSA were observed in approximately 20% of the patients and were not related to the presence of known ischaemic heart disease. Three patients developed angina during the procedure. Among 12 patients with known angina only one patient developed angina during the procedure. In this study chest pain was infrequent (3%), but there was a relative high frequency of ECG changes (20%) not related to patients with ischaemic heart disease only. It is concluded that there is a risk of cardiac events during i. v. DSA, but the risk is not increased in patients with known ischaemic heart disease (if they do not suffer from congestive heart failure) as compared with other patients without known ischaemic heart disease.

A decision scheme for coronary angiography after acute myocardial infarction.

It is important to select patients in the convalescent phase of acute myocardial infarction in whom knowledge of coronary anatomy may identify those potentially suitable for intervention aimed at improving prognosis. However, differing guidelines have been proposed, and by applying some of these guidelines to our large database of patients after acute myocardial infarction, several problem areas were identified. These include lack of considering patients with resting ischemia beyond day 5 of hospitalization, management of patients with reduced ventricular function or patients not exercise tested, and the role of coronary angiography in the elderly. Based on this experience and further analysis in 1,848 patients surviving beyond day 5 of hospitalization, a modified decision scheme for coronary angiography was developed and then tested in a second population (n = 780). In the new scheme, patients over 75 years of age are considered individually. Those under 75 years of age with severe resting ischemia in the hospital at any time beyond the first 24 hours (18% mortality between day 6 and year 1), and hospital survivors with a history of previous myocardial infarction and clinical or radiographic signs of left ventricular failure in the hospital (25% 1-year mortality after discharge), are recommended for coronary angiography. Among the remaining patients, some will perform an exercise test, and those with an ischemic response or poor workload (11% 1-year mortality) are also assigned to coronary angiography. When an exercise test is not performed, a resting radionuclide left ventricular ejection fraction is recommended, and coronary angiography is considered if the value lies between 0.20 and 0.44 (12% 1-year mortality). This relatively simple scheme does not make general recommendations in the elderly, considers patients with in-hospital left ventricular failure or reduced left ventricular function or both, and approaches the problem of patients who do not perform an exercise test. This general approach would avoid early coronary angiography in patients with an average 1-year mortality risk after discharge of 3% and recommend coronary angiography in those at increased risk (average mortality rate, 16%) who make up about 55% of this population under 75 years of age.

Right and left ventricular ejection fractions: relation to one-year prognosis in acute myocardial infarction.

Right and left ventricular ejection fractions (RVEF and LVEF) were measured by radionuclide angiography in 423 patients with acute myocardial infarction (AMI). All investigations were performed at hospital discharge. Of 304 patients with first AMI, 26% had normal ejection fractions, 10% had a decrease in RVEF only, 46% a decrease in LVEF only, and 18% decrease in both RVEF and LVEF. Death from cardiac causes occurred in 52 patients in a one-year follow-up period. A reduced RVEF at hospital discharge had little, if any, relation to one-year mortality. In contrast, there was an inverse curvilinear relationship between LVEF and one-year cardiac mortality.

Silent cerebral infarction in chronic atrial fibrillation.

Atrial fibrillation (AF) is associated with an increased risk of stroke. In AF patients with acute stroke, cerebral computed tomography (CT) often reveals old asymptomatic infarcts. To investigate the frequency of such lesions, 29 AF patients and 29 controls in sinus rhythm without history of cerebrovascular disease were CT scanned. Fourteen patients with AF (48%) had abnormal CT scans with areas of low density with sharp demarcation from surrounding tissue compared with 8 patients in sinus rhythm (28%) (p greater than 0.10). However, the number of abnormal areas with apparent tissue loss was significantly higher in the AF group (39 lesions) compared with the control group (16 lesions) (p = 0.033). The lesions were mainly located in the cortex with no significant difference in lesion size between AF patients and controls. The abnormal areas probably reflected small, clinically silent infarcts. We conclude that these lesions are present in AF patients without history of cerebrovascular events and occur more frequently than in controls without atrial fibrillation.

A study of tail tip necrosis in young fattening bulls on slatted floors.

A questionnaire sent to 78 producers revealed that tail tip necrosis was seen only in units with fattening bulls housed on slatted floors. Out of 43 such units, 20 (46.5 per cent) reported that tail tip necrosis was a herd problem. All 43 herds were visited, owners were interviewed and housing and management data recorded. It is concluded that tail tip necrosis is a multifactorial disease. The initial lesion is caused by tramping, but the following factors are essential in the development and severity of the disease, i) slatted concrete floors, ii) close confinement, iii) hot season and iv) body weight above 200 kg. The stocking density (expressed as kg bodyweight per square meter pen) was significantly higher in problem herds (210 kg/m2) than in control herds (165 kg/m2). There was a close relationship between high environmental temperature and tail tip necroses. The majority of incidents occurred during the warm season (May through September), very few cases were seen during the colder months. The general morbidity and mortality rates were significantly higher in problem herds than in control herds. Microbiology of affected tails revealed mixed infections in most cases, with Corynebacterium pyogenes and Bacteroides melaninogenicus as the most frequently isolated organisms. Principles of treatment and prevention are discussed. There is evidence to assume that a 10-20 per cent reduction in stocking density could be an efficient prophylactic measure.

Failure of transdermal nitroglycerin to improve exercise capacity in patients with angina pectoris.

Sixteen patients with stable angina pectoris were studied in a double blind crossover manner utilizing treadmill exercise testing with the direct measurement of total body oxygen uptake, 1 and 24 hours after application of a 20 cm2 transdermal nitroglycerin system and identical placebo. Testing was performed after a 3 day lead-in period of treatment with either an active patch or placebo. Points of analysis were peak angina and the submaximal work load occurring at 4 minutes of exercise. No statistically significant differences were observed between nitroglycerin and placebo treatment in any of the rest hemodynamic or peak angina variables at 1 or 24 hours. A significant increase in the rate-pressure product at the submaximal work load was observed 1 hour after transdermal nitroglycerin relative to placebo application. However, no significant differences were observed in any of the other measured variables at the submaximal work load, 1 or 24 hours after nitroglycerin application. The once daily application of a 20 cm2 transdermal nitroglycerin system was ineffective in altering the exercise capacity of patients with angina pectoris. The lack of efficacy at 1 hour appears to be due to inadequate nitroglycerin blood levels; at 24 hours it may be due to tolerance.

Dynamic evaluation of short-term prognosis after myocardial infarction.

The risk of cardiac arrest, cardiogenic shock or death in the first 44 days after myocardial infarction is evaluated using a version of the Cox regression model. The (time-dependent) covariates include complications that have occurred, making it possible to give an individual assessment of prognosis that can be updated each day. Low risk patients can be discharged from hospital after a few days, whereas high risk patients must remain in hospital until their risk has fallen to an acceptable level. For the former group of patients it is possible to reduce the number of days in hospital without increased mortality and for the latter group mortality can be reduced by longer hospitalization.

Characterization of Pasteurella species isolated from lungs of calves with pneumonia.

During routine bacteriological examination of pneumonic calf lungs it was experienced that many Pasteurella multocida-like isolates had a fermentation pattern different from what is generally accepted for P. multocida sensu stricto. Forty-one out of 50 strains selected for further investigation were phenotypically related and formed a group of indole-, mannitol-and sorbitol-negative P. multocida-like strains, which was tentatively designated taxon 13. Deoxyribonucleic acid/deoxyribonucleic acid hybridizations including both ornithine positive and ornithine negative strains of taxon 13 allowed the classification of the former as P. multocida biovar 6 and the latter as V factor independent strains of Haemophilus avium.

Usefulness of the chest x-ray for predicting abnormal left ventricular function after acute myocardial infarction.

We evaluated 229 patients discharged after a definite acute myocardial infarction. Pulmonary venous congestion determined from chest x-ray films during the hospitalization and at discharge and the cardiothoracic ratio at discharge were compared to the left ventricular ejection fraction measured at discharge by a gated radionuclide technique. During hospitalization, pulmonary venous congestion was found on at least one x-ray frame in 94 patients (41%). At discharge 134 patients (59%) had abnormal ejection fraction (less than 0.51) and 35 had pulmonary venous congestion (15%). The sensitivity of the x-ray for detecting an abnormal ejection fraction was 20% when pulmonary venous congestion was observed on the discharge x-ray film (specificity 92% and predictive value 77%), 52% if pulmonary venous congestion was present on any x-ray film during the hospitalization (specificity 74% and predictive value 73%), and 47% if the cardiothoracic ratio was abnormal (greater than or equal to 0.50) on the discharge x-ray film (specificity and predictive value 66%). We conclude that an abnormal x-ray film at discharge or during the hospitalization will identify approximately one-half of the abnormal ejection fractions at the time of hospital discharge. Therefore, to reliably assess left ventricular function, either for prognostic or therapeutic purposes in the individual patient, a more direct measure of left ventricular function such as radionuclide angiography must be obtained.