[The effects of nifedipine and captopril on blood pressure, clinical chemical parameters and general health]. / Nifedipins og captoprils effekt på blodtrykket, klinisk-kemiske parametre samt almenbefindendet.

The anti-hypertensive effects of slowly absorbable nifedipin in doses of 20-40 mg twice daily and 25-50 mg captopril twice daily were investigated in a randomized cross-over trial on 19 patients with slight to moderate hypertension. Both of these preparations caused significant reduction in the diastolic blood pressure (BT) measured two and 12 hours after the last dose. Nifedipin caused 5% reduction of the diastolic blood pressure measured 12 hours after the last dose more frequently than did captopril. Where both preparations were concerned, the blood pressure measured two hours after the last intake of medicine was significantly lower than after 12 hours. Neither of the two anti-hypertensive preparations resulted in changes in the clinical-chemical variables measured here. No changes in weight of over 5% were observed. Treatment with nifedipin frequently resulted in headache and flushing during the first days of treatment. Three of the patients did not wish to continue nifedipin treatment and one did not wish to continue captopril treatment after the period of observation. Six patients experienced considerably improved general health during captopril treatment and three during nifedipin as compared with their condition prior to treatment.

Lower chronic stimulation threshold in the carbon-tip than in the platinum-tip endocardial electrode: a randomized study.

Seventy-nine patients admitted for VVI pacemaker treatment were randomly given a Siemens-Elema 412 S endocardial electrode (tip material vitreous carbon, tip area 12 mm2) (41 patients) or a Siemens-Elema 415 S endocardial electrode (tip material platinum, tip area 12 mm2) (38 patients). The groups did not differ in age, sex, magnitude of intracardiac signal or indication for pacemaker treatment. Pacing threshold was measured by the vario technique at 3 and 15 months after the implantation. In the group of carbon-tip electrodes and in the group of platinum-tip electrodes stimulation thresholds at implantation were 0.49 +/- 0.10 V and 0.54 +/- 0.14 V (ns), at months 31.40 +/- 0.45 V and 1.57 +/- 0.53 V (ns), and at months 15 1.12 +/- 0.33 V and 1.37 +/- 0.38 V (P = 0.003), respectively. After 1 year, 88% of the patients in the carbon-tip group and 66% (P = 0.04) in the platinum-tip group fulfilled our criteria for reducing pacemaker output from 5.0 V to 2.5 V. In comparable platinum-tip and carbon-tip pacing electrodes, the chronic stimulation threshold was lower in the carbon-tip than in the platinum-tip electrode.

[Thyrotoxicosis in patients hospitalized because for atrial fibrillation]. / Tyreotoksikose hos patienter indlagt med atrieflimren.

The thyroid parameters were investigated in 99 out of 167 patients with atrial fibrillation as the main diagnosis during a period of two years. Out of these, 22 had current or previous thyrotoxicosis. Sixteen patients with thyrotoxicosis out of 93 (17%) had raised thyroid parameters in connection with the present admission with atrial fibrillation. The mean age was 72 years. The indication for measurement of the thyroid parameters in the 16 patients with thyrotoxicosis and atrial fibrillation was the clinical suspicion of thyrotoxicosis in half of the patients while the remaining half had monosymptomatic atrial fibrillation. Thus, in eight out of 85 patients, the diagnosis of thyrotoxicosis was established solely by screening. Thyrotoxicosis should always be considered as a possible precipitating cause in patients with atrial fibrillation. On account of the frequency (15-20%) and the uncharacteristic symptoms, the thyroid parameters should always be examined routinely.

[Amylase-producing lung tumors]. / Amylaseproducerende lungetumorer.

Raised serum amylase associated with pulmonary tumours is a rare phenomenon. On the basis of two cases, the literature is reviewed and the case histories are compared. The majority of tumours associated with raised serum amylase are adenocarcinomata and, in all of the cases in which determinations of isoenzymes were undertaken, the amylase-isoenzyme was of salivary gland type. In one of the authors' cases, immunhistochemical investigation revealed that the tumour cells contained amylase. In cases of hyperamylasaemia of unknown origin with increased amylase of salivary gland type, adenocarcinoma in the lungs should be considered as a possible diagnosis.

The effect of nifedipine and captopril on platelet activation and prostanoid production in essential hypertension.

Sixteen patients with mild to moderate essential hypertension were randomly allocated to 6 weeks of treatment with nifedipine and captopril in a crossover trial. Nifedipine and captopril lowered blood pressure significantly both 2 and 12 h after the last dose. Apart from an increased heart rate 2 h after the last dose of nifedipine, the heart rate did not change. Platelet factor 4, thromboxane B2, 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) and cyclic (c)AMP did not change during either therapy. There was no correlation between the plasma concentration of nifedipine measured 2 and 12 h after the last dose and the platelet variables described above. The findings show that nifedipine and captopril in therapeutic doses do not affect platelet activity in patients with mild to moderate essential hypertension.

Transseptal left heart catheterization with a Swan-Ganz flow-directed catheter: review of 173 studies.

Of 178 transseptal left heart catheterizations performed, 173 successful cases are reported, with the use of a Swan-Ganz, flow-directed, balloon-tipped catheter. By means of a modified Brockenbrough technique, which is described in detail, a 10F Teflon tube (3.3 mm outside diameter) was inserted into the left atrium. Through the tube, which was continuously flushed with saline solution, a 5F Swan-Ganz catheter was introduced into the left atrium. In all cases where left atrial puncture was possible (n = 173), the left ventricle was easily entered, even in the presence of mitral stenosis. Two major complications with signs of cerebral embolism occurred in this series. The method is technically reliable and acceptably safe in cases where the transseptal route of left heart catheterization is required.

Short-latency ventilatory responses to sudden withdrawal of hypoxia at normal and raised body temperature in man.

Approximately isopnoeic conditions (VE=40 l/min) were achieved by the inhalation of asphyxial gas mixtures (PA,O2 60 torr, PA,CO2 40-45 torr) in normothermia after a rise in rectal temperature of 1.6 degrees C had been induced by a heated flying suit. Arterial chemoreceptor drive was transiently reduced by either isocapnic removal of hypoxia (type (1) tests: two breaths of CO2 in O2) or simultaneous withdrawal of both hypercapnia and hypoxia (type (2) tests: two breaths of O2). 8-13 tests of each type were performed at both temperature conditions in 6 expts. on 4 healthy human subjects. Expired volume, total breath duration and inspiratory time were recorded, and minute ventilation and expiratory time subsequently computed breath by breath. In hyperthermia the steady-state ventilation of 40 l/min (at a relatively higher respiratory frequency and a correspondingly lower tidal volume) was achieved at a PA,CO2 which was 5 torr lower than in normothermia. Ventilation decreased significantly in all tests. Tested with a 3-way analysis of variance significant differences between the ventilatory responses at the two temperature conditions, and between the two test types were found. The rate of change of ventilation was greater in hyperthermia than in normothermia, and also greater in type (2) tests than in type (1) tests. Since isopnoeic conditions existed prior to the tests, this implies that the arterial chemoreceptor contribution to the total ventilatory drive is increased in hyperthermia. In type (2) tests a significant lengthening of expiratory time was observed in the first test breath. This finding confirms the effect in man of changes in airway PCO2 on lung stretch receptor discharge.

Effects of body temperature on ventilatory response to hypoxia and breathing pattern in man.

The ventilatory response to hypoxia (PAO2 55 and 45 Torr) at each of four levels of PACO2 was studied in five healthy subjects before and after a rise in rectal temperature of 1.4 degrees C had been induced by means of a heated flying suit. At a given level of chemical drive both ventilation and mean inspiratory flow increased after heating, frequency relatively more than tidal volume. In isoventilation comparisons mean inspiratory flow was identical in normo- and hyperthermia, whereas the durations of inspiration (TI) and expiration (TE) were proportionately shortened. It is suggested that a rise in temperature shortens TI by affecting a central "clock" and that TE changes are secondary to changes in end-inspiratory volume. The euoxic CO2 response in hyperthermia was suggestive of multiplication between CO2 and temperature. Hypoxic sensitivity was significantly increased, indicating a temperature effect on the arterial chemoreceptors. The breathing pattern was in either temperature condition identical in euoxia and in hypoxia.

Breathing in man during steady-state exercise on the bicycle at two pedalling frequencies, and during treadmill walking.

1. The breathing pattern, that is the changes in tidal volume (VT), and in inspiratory (TI) and expiratory (TE) durations, has been studied as ventilation increases in exercise. 2. Five healthy subjects were studied in steady-state exercise on a bicycle ergometer, breathing air, at two speeds of pedalling and at six different loads. The pattern was recorded for single breaths. Two of the subjects were also studied while walking on a treadmill with four combinations of speed and gradient. 3. In bicycle exercise, as the CO2 output increased mean VT increased, and mean TI and TE decreased, the absolute decrease in TI being small. The pedalling speed did not affect these relationships. 4. Individual breath durations showed no tendency to group around multiples of the period of rotation of the pedals. 5. In treadmill exercise, no clear influence of stride rate on respiratory rate could be found. The pattern was similar to that found in bicycle exercise. Again no grouping could be found. 6. No evidence of an effect of frequency of limb movement on breathing pattern in submaximal exercise has been found. The selection of breathing pattern seems to be unrelated to the nature of the stimulus but closely geared to the metabolic needs of the body.

Mean and breath-by-breath pattern of breathing in man during steady-state exercise.

1. The breathing pattern, that is the relation between tidal volume (VT) and the inspiratory (TI) and expiratory (TE) durations, has been studied for individual breaths (forty in each steady state). 2. Five healthy subjects were studied in steady-state exercise on a bicycle ergometer breathing air; three of them were also studied in hypercapnia, at rest and during exercise, and two of them also during exercise on a treadmill. 3. Tidal volume and respiratory frequency both increased with work load. The increase in frequency was largely due to a progressive decrease in TE; TI also decreased. 4. At any constant level of respiratory drive (constant work load or chemical load) VT was positively correlated with both TI and TE in more than 95% of cases. 5. A simple model of the respiratory cycle which fits both the observed mean and breath-by-breath patterns and which involves no new assumptions is presented.