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Biomedical subjects

B von Breska

Publications and source records attributed to B von Breska.

8 recordsLinked to original sources
PubMed1995

Obstructive sleep apnoea and signal averaged electrocardiogram.

Patients with obstructive sleep apnoea demonstrate an increased rate of ventricular arrhythmias. The present study was designed in order to investigate whether these arrhythmias may be related to myocardial injury, since myocardial injury of various aetiologies has been observed to change the signal averaged electrocardiogram (ECG). Signal averaged ECG was registered in 23 patients with obstructive sleep apnoea diagnosed by polysomnography (apnoea index 43 +/- 20 events.h-1, age 55 +/- 10 yrs). QRS duration, root mean square voltage of the last 40 ms of QRS, and low amplitude (< 40 mV) signal duration were determined from the vector magnitude of the QRS, high-pass filtered at 40 Hz. Patients with coronary heart disease or bundle branch block were excluded. No patient showed an abnormal signal averaged ECG. Mean duration of the filtered QRS complex was 96 +/- 9 ms, root mean square voltage 38 +/- 18 microV and low amplitude signal duration 26 +/- 8 ms. These results were not significantly different from 14 snoring subjects with an apnoea/hypopnoea index < 10. Four patients showed no ventricular arrhythmias and six patients had Lown III or IVa in the Holter ECG. Echocardiography revealed increased left atrial (43.7 +/- 4.1 mm) and interventricular septal diameters (11.3 +/- 1.4 mm). In conclusion, obstructive sleep apnoea does not generate a substrate for late potentials in the signal averaged ECG.

Arrhythmias, Cardiac↗
PubMed1995

[Therapy of Cheyne-Stokes respiration with nocturnal oxygen therapy].

Cheyne-Stokes respiration is common in patients with severe congestive heart failure and is associated with significant nocturnal oxygen desaturation and sleep disruption. The pathogenesis of Cheyne-Stokes respiration in patients with congestive heart failure has been well described and is related to prolonged circulation time between the lung and the carotid body mainly due to increased cardiac dimensions, reduced body stores of oxygen and carbon dioxide, disturbance of ventilation and respiratory control due to arousals and a relatively high hypercapnic ventilatory response. Oxygen is likely to reduce Cheyne-Stokes respiration by increasing oxygen and carbon dioxide stores and reduces the hypercapnic ventilatory response. In the following paper we describe a study designed to determine the impact of nasal nocturnal oxygen on Cheyne-Stokes respiration, sleep, peak oxygen consumption during bicycle exercise, cognitive function evaluated by the trailmaking test and daytime symptoms in patients with severe congestive heart failure. The study is designed as a randomized, cross-over, double-blind, placebo-controlled protocol on about 20 patients with a left ventricular ejection fraction < 35%.

Arousal↗
PubMed1994

[Spontaneous echo contrast in the left ventricle as an indicator for an increased risk of thromboembolism].

A 69-year-old man with coronary heart disease complained of pain in his right flank. He had dyspnoea, cough and fever up to 38.8 degrees C. In addition to various positive indicators of inflammatory disease he had a creatinine concentration of 1.8 mg/dl and an increased activity of lactate dehydrogenase (1655 U/l). The chest radiograph demonstrated pneumonia and computed tomography showed an infarct in the right kidney. The ECG indicated atrial fibrillation with an irregular ventricular rate and left bundle branch block. Echocardiography demonstrated dilatation of the left ventricle and a thrombus adherent to the wall. Transoesophageal echocardiography additionally recorded spontaneous type I echo-contrast, which disappeared after therapeutic heparinization. Cerebral infarctions were shown by computed tomography, undertaken because of neurological symptoms. There were also signs of silent myocardial ischaemia. As a coronary artery bypass operation was contraindicated, percutaneous transluminal balloon angioplasty was attempted but dissection occurred, causing irreversible cardiogenic shock of which the patient died.

Aged↗
PubMed1993

Periodic respiration in patients with heart failure.

Patients with heart failure are known to demonstrate periodic respiration (PR) during sleep. The factors causing PR are not well known. We therefore studied 20 patients (aged 18-66 years) with idiopathic dilated cardiomyopathy. Full-night polysomnography and evaluation of respiration and transcutaneous oxygen saturation were performed. Hypercapnic ventilatory response (HCVR) was evaluated during daytime. The patients showed PR for 25 +/- 26% (mean +/- standard deviation) of total sleep time. During PR, oxygen desaturated 7.1 +/- 4.6%. Sleep was impaired. HCVR was normal. Oxygen desaturation during PR was predicted by HCVR (r = 0.47, P < 0.05) and left atrial diameter (r = 0.60, P < 0.05). The time period of PR expressed as a fraction of total sleep time was correlated with HCVR (r = 0.45, P < 0.05) and left atrial diameter (r = 0.51, P < 0.05). In conclusion, PR with oxygen desaturation, arousals, and impaired sleep was observed in stable heart failure. HCVR and left heart dimensions were related to PR. These findings confirm the concept of a feedback loop describing respiratory control in PR.

Adolescent↗
PubMed1993

Validation of automated sleep stage and apnoea analysis in suspected obstructive sleep apnoea.

Full-night polysomnography is necessary for the diagnosis of obstructive sleep apnoea (OSA). However, analysis of the sleep stages and apnoeas is time-consuming. Computer systems for automated analysis have, thus, been developed to alleviate this task. We investigated 27 consecutive patients referred to our sleep laboratory with suspected OSA. The analysis of sleep stages and apnoeas was performed by visual scoring, according to Rechtschaffen and Kales, and by commercially available automated analysis device. The mean difference between visual scoring and automated analysis was -1, 111, -140, -3, 1 and 27 min, for sleep stages awake, I, II, III, IV and rapid eye movement (REM) respectively. For the apnoea index, the automated analysis rated a lower figure (mean difference 7.h-1, 95% confidence interval 2-12.h-1). The diagnosis of OSA was performed with a sensitivity of 85% and a specificity of 93% by automated analysis. Comparison of two independent handscores showed good agreement, with a mean difference of 6, 4, 3, -7, 1 and -1 min, for sleep stages awake, I, II, III, IV and REM, respectively. In conclusion, the automated analysis underestimates stage I sleep and the apnoea index. Visual scoring is advisable for control of the results. Automated analysis should only be used by those who are able to perform a visual analysis.

Aged↗
PubMed1992

Changes in heart rate during obstructive sleep apnoea.

The mechanisms behind the decrease in heart rate during apnoeas in patients with obstructive sleep apnoea (OSA) are little known. Recent findings in animal experiments indicate that stimulation of the upper airway activates postinspiratory and cardiac vagal neurones in the medullary respiratory centre, causing alterations in heart rate and respiratory rhythm. Since OSA leads to a collapse of the airway and consequent stimulation of upper airway receptors, we studied the interrelations between heart rate and respiratory rhythm during apnoea and during negative intrathoracic pressure generated by the Mueller manoeuvre (MM). Fifteen patients with OSA (apnoea hypopnoea index (AHI) 45 +/- 28.h-1) were studied by polysomnography, during a MM and a Valsalva manoeuvre, each of 15 s duration. The heart rate decrease (delta HRA) and the increase in total respiratory cycle duration (TOT) were evaluated during apnoea in non-rapid eye movement (REM) sleep. Patients with OSA demonstrated a decrease in heart rate during apnoea (-14.4 +/- 9.0 beats.min-1), and during MM (-11.5 +/- 13.5 in OSA vs 3.1 +/- 7.8 beats.min-1 in a control group). TOT increased during apnoea (4.6 +/- 3.1 s). There was a significant correlation between delta HRA and AHI (r = -0.64) as well as between delta HRA and increase in TOT (r = 0.62). These findings indicate that upper airway obstruction may cause an activation of receptors at the site of airway collapse or distortion leading to changes in heart rate and respiratory rhythm.

Female↗
PubMed1990

[Hypersensitivity pneumonia caused by sulfonamides].

A 59-year-old man with Duhring's disease (herpetiform dermatitis) developed undulating fever and pulmonary infiltrates soon after sulfapyridine treatment was started. When the drug was discontinued, a positive provocation test unequivocally established the diagnosis of hypersensitivity pneumonia. There was also a cross-reaction with sulfonyldianiline (dapsone). This case illustrates the need of considering a hypersensitivity reaction as the cause of fever and (or) pulmonary infiltration during sulphonamide administration.

Cross Reactions↗