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Biomedical subjects

L Grote

Publications and source records attributed to L Grote.

48 records · Page 3Linked to original sources
PubMed1995

Arterial hypertension and sleep apnoea: effect of the angiotensin-converting enzyme (ACE) inhibitor cilazapril on continuously measured blood pressure during sleep and wakefulness.

Male patients with arterial hypertension and obstructive sleep-related breathing disorders (mean age 50 y, Body Mass Index (BMI) 32.4 kg m-2, Respiratory Disturbance Index (RDI) 47.2 and systolic/diastolic blood pressure (SBD/DBD) 162/103 mmHg) were examined before and after 8 days of treatment with the long-acting angiotensin-converting-enzyme (ACE) inhibitor cilazapril 2.5 mg vs. placebo in a double-blind design with parallel groups. Cardiorespiratory polysomnography was carried out at night; during daytime wakefulness patients submitted to examinations of physical and mental exertion. Cilazapril reduced the mean pressure during the entire examination period (day and night) by 9.55 (SD +/- 7.13) mmHg, compared to 4.57 (SD +/- 7.20) mmHg for placebo (P < 0.006), independently from systematic changes of heart rate (x = -3.3 and -3.5 bpm, respectively). During REM sleep, mean arterial pressure was significantly reduced by 8.63 (SD +/- 10.1) mmHg, compared to a reduction on placebo of 3.17 (SD 9.6) mmHg (P = 0.023). Under psychometric strain, the mean arterial pressure was reduced by 15.31 (SD +/- 8.7) mmHg with cilazapril; under placebo medication by 6.19 (SD +/- 7.3) mmHg (P < 0.0001). Heart rate was not significantly changed.

Journal Article↗
PubMed1995

Intrathoracic pressure changes and cardiovascular effects induced by nCPAP and nBiPAP in sleep apnoea patients.

The effect of nasal continuous positive airway pressure (nCPAP) and nasal bi-level positive airway pressure (nBiPAP) on intrathoracic pressure and haemodynamics during wakefulness was studied in a group of nine patients with severe sleep apnoea. No patient took cardiovascular medication. Patients were studied with a Swan Ganz catheter, an arterial line and an oesophageal balloon. nCPAP and nBiPAP were applied in the following pressure sequence: 5, 10 and 15 cm H2O of CPAP and 10/5 and 15/10 cm H2O of nBiPAP. Measurements were made at the end of a 5-min period at each pressure level. Intrathoracic pressure was noted to increase to a level of approximately 50% of the pressure delivered at the mask. At a CPAP of 10 cm H2O and above, as well as at BiPAP of 10/5 or higher, there was a decrease in cardiac output (CO) and cardiac index (CI). CI fell below the normal value in two of the patients. Transmural pulmonary artery pressure (PPAtm) decreased at a CPAP of 15 cm H2O and at both BiPAP levels. Transmural right atrial pressure (PRAtm) decreased at both BiPAP levels. There were no differences in CO, CI, PPAtm and PRAtm between nCPAP and nBiPAP at equal inspiratory pressures. SaO2 increased during BiPAP 15/10 cm H2O, whereas heart rate and arterial blood pressure did not change significantly. The data presented here are consistent with the literature on positive end-expiratory pressure (PEEP) applied via intratracheal tube and are likely to be due to a reduced venous return. It is concluded that nasally applied positive pressure may have acute negative effects on cardiac function in patients with sleep apnoea.

Journal Article↗
PubMed1995

Changes in upper airway resistance during progressive normocapnic hypoxia in patients with obstructive sleep apnoea syndrome.

The responses of the upper airway to progressive normocapnic hypoxia were studied in 6 healthy men and in 6 patients with obstructive sleep apnoea syndrome (OSAS). The upper airway resistance was calculated by the ratio of the laryngeal pressure (measured using a catheter introduced into oesophagus) to the inspiratory flow. Additionally, genioglossal EMG activity (GG-EMG) was measured and analysed. The changes of all variables were analysed individually for each subject. The OSAS patients showed reduced ventilatory response, GG-reactivity and changes in upper airway resistance during progressive hypoxia. It is concluded that impaired reactivity to hypoxic activation (probably due to the process of adaptation of carotid chemoreceptors to nocturnal hypoxia), might reduce the defence abilities of OSAS patients against episodes of obturation in upper airway and obstructive apnoea events.

Journal Article↗
PubMed1995

[Nocturnal hypertension and sleep apnea: effect of the ACE inhibitor cilazapril on apnea-induced blood pressure increases during sleep].

The nocturnal increases in blood pressure in cases of obstructive sleep apnea are discussed as causes in connection with increased cardiovascular mortality in sleep apnea. Previous antihypertension therapy studies revealed the antihypertensive action of the ACE inhibitor cilazapril averaged over NREM (NR) and REM sleep (R). In the present study, the effect of this drug on the blood pressure increase within the stress segment of obstructive apnea in NR and R was investigated in a double-blind randomized study versus placebo. Data were collected in digital form with the help of cardiorespiratory polysomnography and intra-arterial blood pressure measurements; a total of 640 apnea in 16 patients were evaluated. Relevant increases in blood pressure occurred during the apnea which were, as expected, more pronounced in R (150/74 mmHg) than in NR (135/69 mmHg). The antihypertensive action of cilazapril was also stronger in R (systole--11.9/diastole--6.4 mmHg) than in NR (systolic--9.0 mmHg/diastolic--5.7 mmHg). Placebo caused significantly lower decreases in blood pressure (systolic--3.7 mmHg/diastolic--2.4 mmHg in R, systolic--2.8 mmHg/diastolic--1.8 mmHg in NR). Thus, evidence is provided for a clinically relevant blood pressure lowering effect of the drug cilazapril on the stress-induced blood pressure increases accompanying obstructive apnea both in NREM and in REM sleep.

Adult↗
PubMed1995

Manifestations and consequences of obstructive sleep apnoea.

Over the last two decades the diagnostic tools used in sleep medicine have developed enormously, making it possible to study the interaction of sleep-related breathing disorders (SRBD) with cardiovascular function and the autonomic nervous system, as well as the effects of SRBD on a variety of physiological processes during wakefulness. Different modes of nasal ventilation are now available, allowing all forms of SRBD to be treated. If early diagnosis and treatment are provided, the acute and long-term sequelae of SRBD can be prevented. In addition to the care and treatment of patients with severe obstructive sleep apnoea syndrome (OSAS), future patient management will need to focus on patients with milder forms of obstructive sleep apnoea (OSA). In particular, the consequences of SRBD on cardiac arrhythmias, arterial hypertension and hypersomnolence are discussed, considering epidemiological, clinical, diagnostic and therapeutic aspects. Some economical issues arising from SRBD are also discussed, and the authors conclude that a Europewide programme for early detection, treatment and prevention of SRBD is required. This could make a large contribution to the reduction of cardiovascular morbidity and mortality and also reduce the incidence of "human error catastrophes" due to hypersomnolence.

Arrhythmias, Cardiac↗
PubMed1994

Twenty-four-hour blood pressure control: effect of cilazapril on continuous arterial blood pressure during sleep, and physical and mental load in patients with arterial hypertension and sleep apnea.

To assess the effectiveness of cilazapril in regulating blood pressure (BP) in patients with sleep-related breathing disorders, 23 male patients (mean age, 50 years; mean body mass index, 32.7 kg/m2) with a mean apnea/hypopnea index of 49.7 and arterial hypertension (163/104 mm Hg) participated in a placebo-controlled, randomized, double-blind study. They received either cilazapril, 2.5 mg/day (n = 12) or placebo (n = 11). The effects of treatment were studied under different conditions of sleep and physical and mental load before and after 8 days of treatment. Measurements by night included cardiorespiratory polysomnography, inductive plethysmography, pulse oximetry and nasal air flow, electroencephalography, (EEG), electrooculography and electromyography, (ECG), and blood pressure (BP). Measurements by day (ECG, heart rate, and BP) were performed at rest and under physical and mental load. Systolic, diastolic, and mean BP (5 min at night; 1 s during the day), heart rate, apnea and hypopnea index, EEG data, and test reaction times were compared in both groups. The systolic and diastolic BP of patients receiving cilazapril was lower compared to baseline for all physical and mental loads. Mean BP reductions over all standardized loads was greater with cilazapril than placebo (-10 vs. -4.3 mm Hg, p < 0.05). These results show that BP is influenced similarly by mental and physical loads, and that behavior [i.e., awake state and non-rapid eye movement and rapid eye movement (NREM and REM) sleep determines BP regulation. Cilazapril is effective in reducing BP in all situations, especially during REM sleep hypertension.

Adult↗
PubMed1994

Nocturnal hypertension and cardiovascular risk: consequences for diagnosis and treatment.

General use of ambulatory noninvasive 24-h blood pressure monitoring in many patients has shown that new criteria for arterial hypertension are useful. A classification of circadian blood pressure in "dippers" and "nondippers" (no physiologic drop of blood pressure) needs to be specified. An altered circadian blood pressure profile, like that in nondippers, was used as a diagnostic criterion for secondary hypertension. Recent epidemiologic studies in patients with essential hypertension have shown that nondippers are at higher risk for cardiovascular complications such as myocardial infarction and cerebrovascular insult. The studies also revealed that sleep-related breathing disorders (SRBD) are characterized by increased cardiovascular risk. Increases in blood pressure caused by SRBD could be documented, with the highest amount occurring during REM sleep. A study performed in a general practice showed a high incidence (40/112) of nondippers in a group of snoring middle-aged men with obesity and daytime fatigue. This indicates diagnostic and therapeutic consequences for the control of 24-h blood pressure, including nocturnal breathing pattern and daytime symptoms due to SRBD. The goal of antihypertensive drug therapy is to reduce blood pressure significantly during the day and during the night in different stages of wakefulness and sleep. A new protocol was designed to investigate blood pressure over 24 h under a standardized load, including nocturnal hypertension. The angiotensin-converting enzyme (ACE) inhibitor cilazapril was used in this test procedure and showed a significant and clinically relevant mean blood pressure reduction of 10.0 mm Hg (versus placebo 4.3 mm Hg) over 24 h.

Adult↗
PubMed1994

A new method to study blood pressure, heart rate and EEG as a function of reaction time.

A new method is presented to study the relationship between reaction time and blood pressure, heart rate and EEG. The method consists of a simultaneous recording of continuous invasive or non-invasive arterial blood pressure, ECG, EEG, EMG and EOG in a sound-isolated chamber while a monotonous visual reaction time test is running for about 90 minutes. The signals are A/D-converted and analyzed digitally after recording. One second average amplitudes are computed. Systolic, mean and diastolic blood pressure values are calculated, and the EEG is divided into the delta, theta, alpha, sigma and beta frequency bands. The signal amplitudes are averaged in three different reaction time categories, i.e., when the reaction is normal, delayed or missing. Preliminary tests suggest that interesting differences can be observed in the studied variables in different reaction time classes. This method can also be applied to the investigation of autonomic control and to treatment studies.

Blood Pressure↗
PubMed1993

[Validation study of the 10-channel Sidas 2010 registration unit for diagnosis of sleep-related respiratory disorders].

UNLABELLED: We developed in cooperation with F. D. Stott, Oxford, the Mobile 10-Channel Unit SIDAS 10, a recording instrument for diagnosing sleep-related breathing disorders, to cope with the large number of patients requiring to be diagnosed. Studies that have already been published prove the clinical worth of this instrument that has been conceived as a mobile unit for the diagnosis of sleep-related breathing disorders outside a conventional sleep laboratory. To test the validity of this unit the present study was designed as a comparative study of conventional polygraphs versus SIDAS recordings. METHOD: 20 unselected patients (18 men, 2 women), average age 54.8 (34-65) years, body mass index (BMI) 29.8 (20.2-46.2) kg/m2, were examined parallel for one night in the sleep laboratory. We compared the breathing a) recorded with nasal airflow, oesophageal pressure, oxygen saturation and b) with induction plethysmography, ITP (a non-invasive recording of intrathoracic pressure variations), nasal airflow and pulse oxymetry via SIDAS 2010. The writeouts were evaluated visually according to internationally valid criteria. RESULTS: We found 10 patients with an apnoea index (AI) > 10/h (mean AI 53.2), 4 patients with AI between 5 and 10/h (mean AI 6.4) and 6 patients with an AI < 5/h (mean AI 3.4). 5835 apnoeas and hypopnoeas were evaluated. The statistical analyses yielded the following results: equal classification of central apnoeas in 87%, of obstructive apnoeas in 90% and of mixed apnoeas in 92% of the cases; on the whole, 10% more hypopnoeas were classified in the SIDAS recordings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Cardiovascular effects of mibefradil in hypertensive patients with obstructive sleep apnea.

OBJECTIVE: Hypertension is often seen in obstructive sleep apnea (OSA) and is characterized by increased sympathetic activity, depressed baroreflex and accentuated vascular responsiveness. The objective of this study was to investigate the effects of the new T-selective calcium channel blocker mibefradil on invasively measured blood pressure (BP) and heart rate in hypertensive patients with OSA. METHODS: The present study was a double-blind, randomized and placebo-controlled before and after trial in two parallel groups. Fifty-three men aged 23 69 years with systemic hypertension and OSA were recruited from the Outpatient Department of the Marburg University Sleep Laboratory and hospitalized for 10 days. Mibefradil (50 mg) or placebo were given orally in the morning for 8 days. The main outcome measure was the mean arterial (radial) BP monitored continuously during nocturnal sleep and during standardized daytime physical and psychological performance testing. RESULTS: Mibefradil lowered mean arterial BP and heart rate with (SD) during the entire measurement period compared with placebo: -7.25 (9.59) vs -2.11 (8.43) mmHg (P=0.039) and -4.83 (5.94) vs -1.34 (4.13) bpm (P=0.022), respectively. Both effects were observed during nocturnal sleep and performance testing, including graded exercise. Adverse events did not differ compared with placebo. CONCLUSION: Mibefradil is an effective but well-tolerated antihypertensive that also lowers heart rate over 24 h in OSA, in conditions known to increase BP.

Adult↗
PubMedDate not supplied

[Invasive and noninvasive techniques for analysis of cardiovascular effects of sleep apnea].

There is increasing epidemiological and experimental evidence that Sleep Disordered Breathing (SDB) is associated with cardiovascular disease such as hypertension, ischaemic heart disease, heart failure and stroke. Due to the high prevalence of SDB in the general population (5% to 10%) there is increasing demand for cost-effective and reliable diagnostic tools for the assessment of cardiovascular function during sleep in patients with SDB. The first part of this review focuses on our present knowledge about the association between SDB and cardiovascular disease. In the second part various methods for the assessment of cardiac function, blood pressure, sympathetic activity, as well as vascular and cerebrovascular function in patients with SDB are discussed. Current developments such as ECG analysis for SDB screening or arterial tonometry are introduced. Further improvements in the diagnostic tools for the investigation of cardiovascular function in patients with SDB may to advantage be coupled with epidemiological studies. This approach may demonstrate the predictive value or superiority of a specific diagnostic parameter in the diagnosis of SDB and its cardiovascular consequences.

Cardiovascular Diseases↗