Biomedical subjects

J H Atterhög

Publications and source records attributed to J H Atterhög.

36 records · Page 2Linked to original sources

PubMed1977

P-R interval in relation to heart rate during exercise and the influence of posture and autonomic tone.

P-R interval (PR) in relation to heart rate (HR) during exercise was studied in healthy men. When subjects were in a recumbent position, mean PR between HR 90-140 beats/min (bpm) decreased linearly from 167 +/- 8 ms to 136 +/- 5 ms. (Regression line: PR = 0.287 HR + 182.9, r = 0.40). PR did not decrease further at HR up to 180 bpm. When subjects were in a sitting position, a further decrease occurred after HR 150-160 bpm. The shortest PR observed during exercise was 100 ms. The decrease of PR between HR 90-140 bpm was affected by atropine but not by propranolol. Higher HR was not achieved after propranolol, and after atropine there was no difference in PR in either exercise position compared to the two exercises without any drug. Thus, exercise induces a decrease in PR which is for the most part completed at HR 140-150 bpm and is mainly achieved by a withdrawal of the parasympathetic tone. PR at HR 90 bpm was correlated to body surface area, indicating that the PR duration is related to the body and heart dimensions.

Adult↗

PubMed1977

Hemodynamic effect of long--term treatment with pindolol in essential hypertension with special reference to the resistance and capacitance vessels of the forearm.

Ten patients with essential hypertension have been studied at rest, during and after exercise following oral treatment for on an average 16 months with a beta-adrenoreceptor blocking agent, pindolol. The study was a direct continuation of an earlier, performed after 2 months' treatment. The hypotensive effect of pindolol was highly significant after 2 as well as 16 months of treatment. Heart rate was similarly lowered at 2 and 16 months, while carciac output, which was significantly lower during exercise after 2 months, had increased to the pretreatment level after 16 months. Peripheral vascular resistance, which was not affected after 2 months, had decreased significantly during and after exercise in the long-term study. A comparison between the hemodynamic situations after 2 and 16 months thus suggests that while a decrease in cardiac output is an early mechanism in the lowering of BP, changes in systemic vascular resistance seem to be more important after long-term treatment with pindolol.

Administration, Oral↗

PubMed1977

Haemodynamic effects of pindolol in hypertensive patients.

Five men and five women, mean age 48 years, with hypertension in stages I or II of the WHO classification, were given preoral treatment with pindolol. The pindolol treatment lead a significant decrease in the systolic and diastolic blood pressure, at rest and during work both after 2 months and after 16 months treatment. Three mechanisms seem to be involved in the antihypertensive effect of pindolol: 1) a negative chronotropic effect on the heart, 2) a decrease in peripheral vascular resistance and 3) an increase in venous capacitance affecting the venous return. Comparison of the results after 2 and after 16 months of treatment suggests that a decrease in cardiac output is an early mechanism in the lowering of the blood pressure, while a decrease in vascular resistance seems to be more important after long-term treatment with pindolol.

Cardiac Output↗

PubMed1977

The significance of AV block I in asymptomatic young men. Variability, some anthropometric data, orthostatic test reaction and physical work capacity.

Twenty-nine young men with AV block I (P-R interval greater than 0.22 sec), without any history of heart disease, have been compared with 112 randomly selected healthy men of the same age. In 24 subjects who were free from concomitant ECG changes the P-R interval was normalized during orthostatic test and/or physical exercise. This group did not differ from the controls regarding anthropometric data and physical work capacity except for a higher heart rate at rest, thus suggesting that in these subjects an occurrence of AV block I has no pathological significance. However, it cannot be excluded that the block is a sequela, for instance, to myocarditis. Three subjects with AV block I and inverted T waves in the precordial leads and two subjects with unchanged P-R intervals to increased sympathetic tone had on average a smaller body size, a higher HR and systolic BP in recumbent position and smaller blood volumes.

Adolescent↗

PubMed1976

Experience with pindolol, a betareceptor blocker, in the treatment of hypertension.

Ten patients, mean age 48 years, with essential hypertension of stage I and II according to the WHO classification, were studied at rest and during work before and after an average of two and 16 months of oral treatment with the beta-adrenergic blocking agent, pindolol. The pindolol treatment caused a significant decrease in the systemic systolic and diastolic blood pressure, both at rest and during work. Three mechanisms seem to be involved in the antihypertensive effect of pindolol: (1) a negative chronotropic effect on the heart, (2) a decrease in peripheral vascular resistance, and (3) an increase in venous capacitance affecting the venous return. However, the significance of these mechanisms seems to differ when the situations after two months of treatment are compared with those after 16 months of treatment. In the beginning, a decrease in cardiac output seems to be the main cause of the lowering of the blood pressure; later, a decrease in systemic vascular resistance might be of greater importance.

Adrenergic beta-Antagonists↗

PubMed1976

On-line computer processing of pressure data from cardiac catheterizations.

A flexible program system for on-line analysis of pressure data from cardiac catheterizations is described. The programs are implemented on an IBM 1800 computer, equipped with remote oscilloscope/keyboard terminals. The current computer system can handle any combination of up to 4 pressure signals. During catheterization, measurement specifications (i.e. calibration levels or sites of pressure recordings) are entered via the keyboard immediately before each recording. As an option the whole expected measurement sequence may be stored on disk before the catheterization starts. This method will minimize the necessary interaction with the computer when the same catheterization procedure is used on several occasions. Changes from the predetermined scheme may, however, be undertaken before each recording to meet with unexpected events that may arise during the catheterization. After computer detection of calibration levels, the recorded signals are digitized during 20 seconds and analysed beat-by-beat. Calculated values are averaged and presented on the terminal oscilloscope in tabular and/or graphic form. The waveform analysis performed by the program system is validated in a statistical comparison between manually and automatically computed values.

Cardiac Catheterization↗

PubMed1976

Measurement of cardiac output by impedance cardiography in patients with myocardial infarction. Comparative evaluation of impedance and dye dilution methods.

The cardiac output was measured simultaneously by the impedance cardiography and dye dilution methods in 10 patients with acute myocardial infarction 2-3 weeks after admission to the Coronary Care Unit. The impedance cardiac output was on the average 9.7% higher than the dye dilution cardiac output. The reproducibility of impedance cardiac output 4.1%, compared with 5.1% for the dye dilution method. The study showed a satisfactory reliability of impedance in predicting the relative changed of cardiac output in response to tilting from the supine to the 30 degrees head-up position, to a 10 degrees head-down position, and to the intravenous administration of propranolol.

Acute Disease↗

PubMed1976

Hemodynamic effect of pindolol in essential hypertension with special reference to the resistance and capacitance vessels of the forearm.

Ten patients, mean age 48 years, with essential hypertension of stage I and II according to the WHO classification, have been studied at rest and during work before and after on average 8 weeks oral treatment with a beta-adrenergic blocking agent, pindolol. The pindolol treatment caused a significant decrease in the systemic systolic and diastolic blood pressure, heart rate and cardiac output both at rest and during work. The systemic vascular resistance and the forearm vascular resistance decreased significantly after and during work, respectively. Forearm venous tone was significantly decreased at rest, during and after work. The plasma renin activity decreased. Three mechanisms seem to be involved in the antihypertensive effect of pindolol: 1) a negative chronotropic effect on the heart, 2) a decrease in peripheral vascular resistance, and 3) an increase in vascular capacitance affecting the venous return.

Adult↗

PubMed1975

Haemodynamic effects of intravenous verapamil at rest and during exercise in subjectively healthy middle-aged men.

Verapamil, 0.1 mg/kg body wt, was injected i.v. over 2 minutes in 8 subjectively healthy middle-aged men, followed by a continuous infusion of 0.007 mg/kg body wt per minute. Prior to the injection several of the subjects had raised pulmonary or systemic arterial pressures. At rest, the central pressures increased slightly, which was taken as a sign of a moderate negative inotropic effect, but there was no change in pre-ejection period or maximal dp/dt of the aortic pressure. The heart rate increased and there was a small decrease in systemic arterial pressure, probably due to a fall of systemic vascular resistance. The PQ time was prolonged. During exercise, with its positive inotropic stimulation, the moderate negative inotropic effect of verapamil disappeared, whereas the increase in heart rate and decrease in aortic pressures persisted. Some variables that reflected the oxygen demand of the heart decreased. The slight negative inotropic effect does not appear to be a particular contraindication to the use of verapamil, but it should be employed cautiously in conditions with a compensatory rise in systemic vascular resistance, or if atrioventricular conduction is impaired.

Adult↗

PubMed1975

[The hemodynamic effect of verapamil by intravenous administration in middle-aged, subjectively healthy subjects at rest and during exercise].

After an intravenous injection of 0.1 mg Verapamil per kg body weight and during an infusion of 0.007 mg Verapamil per kg body weight and minute the heart rate increased, P,Q,-time increased, pulmonary vascular pressures increased. Aortic pressures decreased. No change in maximum dp/dt of the aortic pressure. The word maximum is still missing. Pre-ejection period decreased. During an exercise on a load of 650 kpm/min on average heart rate after Verapamil was increased, aortic pressures decreased, stroke work decreased and there were no signs of any negative inotropic effect.

Adult↗

PubMed1975

Effect of nifedipine on exercise tolerance in patients with angina pectoris.

To test if nifedipine, 10 mg sublingually, could increase exercise tolerance, ten patients with angina pectoris each performed two types of bicycle exercise test, one with a stepwise increase in load and the other with a continuously increasing load. The drug was given in a double-blind cross-over trial. Nifedipine raised the heart rate and diminished the systemic blood pressure at rest, on standing and during exercise at comparable loads. Work time was prolonged and higher work loads were achieved. The total work performed rose by 50 per cent in one of the tests and by 23 per cent in the other, about 50 minutes after taking the drug. The mechanism of the greater work capacity in angina pectoris after nifedipine was assumed to be diminished heart work due to a fall in systemic vascular resistance.

Adult↗

PubMed1975

Cardiovascular and renal responses to acute cold exposure in water-loaded man.

Changes in oxygen uptake, cardiac output, heart rate, stroke volume, central blood volume, arteriovenous oxygen difference, aortic, pulmonary arterial, and right atrial blood pressure, systemic vascular resistance, hematocrit, circulating plasma volume, urine flow, fractional sodium excretion, and free water clearance were studied in eight healthy volunteers in stable water diuresis, exposed to cold by means of air at +15 degrees C and at a speed of 0.5 m/sec. A decrease in circulating plasma volume and systemic vascular resistance was found during cold stress. Mean aortic blood pressure, sodium excretion, cardiac output, oxygen uptake, arteriovenous oxygen difference, and hematocrit increased. No changes in urine flow or in clearance of free water could be demonstrated. Heart rate, stroke volume, and central blood volume showed significant increases in cold. The results are interpreted to suggest that exposure to cold raises the arterial blood pressure by an increase in cardiac output, thereby increasing capillary hydrostatic pressure in certain vascular areas, including the renal vascular bed. This negatively affects capillary reabsorption processes in the kidney, causing a reduction in tubular sodium reabsorption, thus giving rise to a natriuresis. In other areas it seems to cause a shift of fluid towards the intersitial space.

Adult↗

PubMed1974