Search results for "Cardiology"

Analysis of Cerebral Vasospasm in a Murine Model of Subarachnoid Hemorrhage with High Frequency Transcranial Duplex Ultrasound

2021

Cerebral vasospasm that occurs in the weeks after subarachnoid hemorrhage, a type of hemorrhagic stroke, contributes to delayed cerebral ischemia. A problem encountered in experimental studies using murine models of SAH is that methods for in vivo monitoring of cerebral vasospasm in mice are lacking. Here, we demonstrate the application of high frequency ultrasound to perform transcranial Duplex sonography examinations on mice. Using the method, the internal carotid arteries (ICA) could be identified. The blood flow velocities in the intracranial ICAs were accelerated significantly after induction of SAH, while blood flow velocities in the extracranial ICAs remained low, indicating cerebral…

Stroke and cardiac arrhythmias.

2001

Stroke is frequently followed by electrocardiographic (ECG) changes. The aim of the present study was to evaluate the global incidence of these changes after ischemic or hemorrhagic strokes, but it focused on cardiac arrhythmias. In ischemic strokes, these were correlated with the side of the lesion(s). The study was retrospective, and 450 patients (out of 971 examined) were entered in the study based on the following inclusion criteria: (1) "completed" stroke (352 ischemic and 98 hemorrhagic), (2) ECG on admission, and (3) at least 1 previous ECG. We also examined 71 patients with carotid or vertebro-basilar transient ischemic attacks (TIA). As controls, 71 patients suffering from nonvascu…

The Role of Erythropoietin in Aneurysmal Subarachnoid Haemorrhage: From Bench to Bedside

2014

Subarachnoid haemorrhage (SAH) caused by a ruptured aneurysm accounts for only 5 % of strokes, but occurs at a fairly young age and carries a poor prognosis. Delayed cerebral ischaemia (DCI) is an important cause of death and dependence after aneurysmal SAH. The current mainstay of preventing DCI is nimodipine and maintenance of normovolemia, but even with this strategy DCI occurs in a considerable proportion of patients.

nrCBF for Timing of Angiography and Operation in Subarachnoid Hemorrhage

1983

Early operation on cerebral aneurysms is demanded not least because of the threat of spasm of the cerebral vessels. As is generally recognized, this is to be expected in a very high percentage within a few days after the first aneurysm hemorrhage and frequently cannot be diagnosed clinically (4, 5). Many neurosurgeons have rated the risk of operating in the presence of vasospasm so high that, like C.G. DRAKE in 1975 (2), they demanded control angiography with its own risk, especially in existing vasospasm in early angiography and the aneurysm operation itself could not take place rapidly.

Hypertrophic cardiomyopathy and fibrosis: correlation between late gadolinium enhancement on CMR and speckle tracking imaging using Ultrasound

2015

Background Hypertrophic cardiomyopathy (HCM) is the most frequent genetic cardiovascular disorder and represents one of the most common cause of heart related sudden death in young adults. Myocardial fibrosis seems to be an independant predictor of adverse events including sudden death, ventricular arrhythmias and heart failure. While late gadolinium enhancement (LGE) on Cardiac Magnetic Resonance (CMR) is actually the gold-standard to detect fibrosis, new techniques are being evaluated such as 2D strain echocardiography.

Causal analysis of short-term cardiovascular variability: state-dependent contribution of feedback and feedforward mechanisms.

2016

Baroreflex function is usually assessed from spontaneous oscillations of blood pressure (BP) and cardiac RR interval assuming a unidirectional influence from BP to RR. However, the interaction of BP and RR is bidirectional—RR also influences BP. Novel methods based on the concept of Granger causality were recently developed for separate analysis of feedback (baroreflex) and feedforward (mechanical) interactions between RR and BP. We aimed at assessing the proportion of the two causal directions of the interactions between RR and systolic BP (SBP) oscillations during various conditions, and at comparing causality measures from SBP to RR with baroreflex gain indexes. Arterial BP and ECG sig…

Role of causality in the evaluation of coherence and transfer function between heart period and systolic pressure in humans

2004

To elicit the effects of considering causality in the study of the interactions between RR interval and systolic pressure (SP) variability, the traditional noncausal cross-spectral analysis was compared with a causal method able to separate the two arms of the RR-SP regulatory loop. Estimates of coherence (K) and causal coherences from SP to RR (Ksr) and from RR to SP (Krs), and of noncausal (G) and causal (Gsr) baroreflex gain were evaluated at 0.1 Hz in 10 healthy young subjects in the supine position and after head-up tilt. While K was high in both conditions, at rest Ksr was significantly lower than Krs. After tilt, Ksr increased and Krs decreased significantly. With respect to G, Gsr w…

2019

Objective: In two independent study arms, we determine the effects of strength training (ST) and high-intensity interval training (HIIT) overload on cardiac autonomic modulation by measuring heart rate (HR) and vagal heart rate variability (HRV). Methods: In the study, 37 well-trained athletes (ST: 7 female, 12 male; HIIT: 9 female, 9 male) were subjected to orthostatic tests (HR and HRV recordings) each day during a 4-day baseline period, a 6-day overload microcycle, and a 4-day recovery period. Discipline-specific performance was assessed before and 1 and 4 days after training. Results: Following ST overload, supine HR, and vagal HRV (Ln RMSSD) were clearly increased and decreased (small …

Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling

2020

Objective: We explored the physiological background of the non-linear operating mode of cardiorespiratory oscillators as the fundamental question of cardiorespiratory homeodynamics and as a prerequisite for the understanding of neurocardiovascular diseases. We investigated 20 healthy human subjects for changes using electrocardiac RR interval (RRI) and respiratory signal (Resp) Detrended Fluctuation Analysis (DFA, α1RRI, α2RRI, α1Resp, α2Resp), Multiple Scaling Entropy (MSERRI1−4, MSERRI5−10, MSEResp1−4, MSEResp5−10), spectral coherence (CohRRI−Resp), cross DFA (ρ1 and ρ2) and cross MSE (XMSE1−4 and XMSE5−10) indices in four physiological conditions: supine with spontaneous breathing, stand…

Regional Lung Blood Perfusion Measured With Laser Doppler Method During Body Position Change, Valsalva Manoeuvre and Cardiopulmonary Bypass

2008

Regional Lung Blood Perfusion Measured With Laser Doppler Method During Body Position Change, Valsalva Manoeuvre and Cardiopulmonary Bypass Methodological approaches to investigate local regulatory mechanisms of lung blood supply in humans are restricted. We tried a new approach using laser Doppler technique. During bronchoscopy, an angled laser Doppler flow probe was introduced through a biopsy channel and wedged into small bronchus. Laser light penetrated the wall of small bronchus and was reflected from blood cells running through neighbouring capillaries. Regional blood perfusion changes were recorded during body position change from vertical to supine and back to vertical, while perfor…