Search results for "Rhythm"
showing 10 items of 822 documents
Safety and feasibility of atropine added in patients with sub-maximal heart rate during exercise myocardial perfusion SPECT.
2006
Failure to reach 80% of maximal predicted heart rate (HR) during exercise may render a myocardial perfusion single photon emission computed tomography (SPECT) study non-diagnostic for ischemia detection. We sought to investigate the injection of atropine in patients who fail to achieve 80% of age-predicted HR during exercise performed for myocardial perfusion SPECT (MPS), defining its safety and efficacy to raise HR to adequate levels as well as its effect on MPS interpretation.Between January 2002 and December 2004, we studied 3,150 consecutive patients (2,253 men and 897 women, mean age 55 +/- 6 years) who were referred to a single office-based nuclear cardiology laboratory for MPS using …
Comprehensive auditory discrimination profiles recorded with a fast parametric musical multi-feature mismatch negativity paradigm
2016
Abstract Objective Mismatch negativity (MMN), a component of the auditory event-related potential (ERP) in response to auditory-expectancy violation, is sensitive to central auditory processing deficits associated with several clinical conditions and to auditory skills deriving from musical expertise. This sensitivity is more evident for stimuli integrated in complex sound contexts. This study tested whether increasing magnitudes of deviation (levels) entail increasing MMN amplitude (or decreasing latency), aiming to create a balanced version of the musical multi-feature paradigm towards measurement of extensive auditory discrimination profiles in auditory expertise or deficits. Methods Usi…
Perceiving rhythm where none exists : Event-Related Potential (ERP) correlates of subjective accenting
2008
Previous research suggests that our past experience of rhythmic structure in music results in a tendency for Western listeners to subjectively accent equitonal isochronous sequences. We have shown in an earlier study that the occurrence of a slightly softer tone in the 8th to 11th position of such a sequence evokes a P300 event-related potential (ERP) response of different amplitudes depending on whether the tone occurs in putatively subjectively accented or unaccented sequence positions (Brochard et al., 2003). One current theory of rhythm processing postulates that subjective accenting is the result of predictive modulations of perceptual processes by the attention system. If this is the …
How is Visual Recognition Entrained by Auditory Background Rhythms?
2014
AbstractRecent studies have reported that the oscillations of auditory attention entrained by a background rhythmic sequence can influence performance in visual recognition tasks. We have designed an experimental paradigm in which a visual item (either a bisyllabic word or a familiar face) is displayed on screen in two consecutive parts while a musical rhythm is played in the background. Depending on the timing conditions, the first or the second part of the item could be presented either in-synchrony or out-of-synchrony with the beats of the auditory rhythm. In a first series of experiments, participants performed a lexical decision task on bisyllabic 5-letter strings. Results show that wh…
Impaired circadian heart rate variability in Parkinson’s disease: a time-domain analysis in ambulatory setting
2020
Abstract Background Heart rate variability (HRV) decreases in Parkinson’s disease (PD) and it can be considered a marker for cardiovascular dysautonomia. The purpose of this pilot study is to evaluate long-term time-domain analysis of HRV of PD patients and compare the results with those of matched healthy individuals. Methods Idiopathic PD patients without comorbidity impairing HRV, and age-matched healthy individuals were recruited in a pilot study. A long-term time domain analysis of HRV using 24-h ambulatory ECG was performed. Results Overall, 18 PD patients fulfilling inclusion criteria completed the evaluation (mean age was 55.6 ± 8.8, disease duration: 5.0 ± 4.7). Mean SCOPA-AUT scor…
Evidence for a dysfunction and disease-promoting role of the circadian clock in the diabetic retina.
2021
Diabetic retinopathy is a major complication of chronic hyperglycemia and a leading cause of blindness in developed countries. In the present study the interaction between diabetes and retinal clocks was investigated in mice. It was seen that in the db/db mouse - a widely used animal model of diabetic retinopathy - clock function and circadian regulation of gene expression was disturbed in the retina. Remarkably, elimination of clock function by Bmal1-deficiency mitigates the progression of pathophysiology of the diabetic retina. Thus high-fat diet was seen to induce histopathology and molecular markers associated with diabetic retinopathy in wild type but not in Bmal1-deficient mice. The d…
Ventricular remodelling in rabbits with sustained high-fat diet.
2013
Aim Excess weight gain and obesity are one of the most serious health problems in the western societies. These conditions enhance risk of cardiac disease and have been linked with increased prevalence for cardiac arrhythmias and sudden death. Our goal was to study the ventricular remodelling occurring in rabbits fed with high-fat diet (HFD) and its potential arrhythmogenic mechanisms. Methods We used 15 NZW rabbits that were randomly assigned to a control (n = 7) or HFD group (n = 8) for 18 weeks. In vivo studies included blood glucose, electrocardiographic, and echocardiographic measurements. Optical mapping was performed in Langendorff-perfused isolated hearts. Results Body weight (3.69 ±…
The effects of 12-week progressive strength training on strength, functional capacity, metabolic biomarkers, and serum hormone concentrations in heal…
2018
Previous findings suggest that performing strength training (ST) in the evening may provide greater benefit for young individuals. However, this may not be optimal for the older population. The purpose of this study was to compare the effects of a 12-week ST program performed in the morning vs. evening on strength, functional capacity, metabolic biomarker and basal hormone concentrations in older women. Thirty-one healthy older women (66 ± 4 years, 162 ± 4 cm, 75 ± 13 kg) completed the study. Participants trained in the morning (M) (07:30, n = 10), in the evening (E) (18:00, n = 10), or acted as a non-training control group (C) (n = 11). Both intervention groups performed whole-body strengt…
Home blood pressure control is low during the critical morning hours in patients with hypertension: the SURGE observational study
2011
Background. The morning blood pressure (BP) surge is associated with a peak increase in vascular events. Objective. The aim of this observational study was to evaluate morning BP control in treated hypertensive patients using home BP (HBP) monitoring and to compare these findings with clinic BP control. Methods. Clinic BP was measured twice during a 2-week period, prior to medication. Seated HBP was measured, using a BHS-validated device, three times per day over a 2-week period. Assessments included morning (06:00–11:59), lunchtime (12:00–14:00) and evening (18:00–22:00) HBP control (all <135/85 mmHg) and clinic BP (<140/90 mmHg) control. Results. A total of 15 618 patients were assessed. …
Microwave effects on isolated chick embryo hearts.
1986
This study was designed to examine the effects of microwaves on the electric activity of hearts as a means of elucidating interactive mechanisms of nonionizing radiation with cardiac tissue. Experiments were performed on isolated hearts of 9-12-day-old chick embryos placed in small petri dishes. Oxygenated isotonic Ringer's solution at 37 degrees C permitted heart survival. Samples were irradiated at 2.45 GHz with a power density of 3 mW/cm2. The heart signal was detected with a glass micropipet inserted into the sinoatrial node and examined by means of a Berg-Fourier analyzer. Pulsed microwaves caused the locking of the heartbeat to the modulation frequency, whereas continuous wave irradia…