scholarly journals Electrocardiographic Imaging for Atrial Fibrillation: A Perspective From Computer Models and Animal Experiments to Clinical Value

2021 ◽  
Vol 12 ◽  
Author(s):  
João Salinet ◽  
Rubén Molero ◽  
Fernando S. Schlindwein ◽  
Joël Karel ◽  
Miguel Rodrigo ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Electrical Activity ◽  
Ventricular Arrhythmias ◽  
Animal Experiments ◽  
Computer Models ◽  
Clinical Results ◽  
Clinical Value ◽  
Electrocardiographic Imaging ◽  
Human Experiments

Electrocardiographic imaging (ECGI) is a technique to reconstruct non-invasively the electrical activity on the heart surface from body-surface potential recordings and geometric information of the torso and the heart. ECGI has shown scientific and clinical value when used to characterize and treat both atrial and ventricular arrhythmias. Regarding atrial fibrillation (AF), the characterization of the electrical propagation and the underlying substrate favoring AF is inherently more challenging than for ventricular arrhythmias, due to the progressive and heterogeneous nature of the disease and its manifestation, the small volume and wall thickness of the atria, and the relatively large role of microstructural abnormalities in AF. At the same time, ECGI has the advantage over other mapping technologies of allowing a global characterization of atrial electrical activity at every atrial beat and non-invasively. However, since ECGI is time-consuming and costly and the use of electrical mapping to guide AF ablation is still not fully established, the clinical value of ECGI for AF is still under assessment. Nonetheless, AF is known to be the manifestation of a complex interaction between electrical and structural abnormalities and therefore, true electro-anatomical-structural imaging may elucidate important key factors of AF development, progression, and treatment. Therefore, it is paramount to identify which clinical questions could be successfully addressed by ECGI when it comes to AF characterization and treatment, and which questions may be beyond its technical limitations. In this manuscript we review the questions that researchers have tried to address on the use of ECGI for AF characterization and treatment guidance (for example, localization of AF triggers and sustaining mechanisms), and we discuss the technological requirements and validation. We address experimental and clinical results, limitations, and future challenges for fruitful application of ECGI for AF understanding and management. We pay attention to existing techniques and clinical application, to computer models and (animal or human) experiments, to challenges of methodological and clinical validation. The overall objective of the study is to provide a consensus on valuable directions that ECGI research may take to provide future improvements in AF characterization and treatment guidance.

IN VITRO UPTAKE OF RADIOACTIVE 131I LABELLED L-TRIIODOTHYRONINE BY HUMAN ERYTHROCYTES AS AN INDEX OF THYROID FUNCTION

1960 ◽  
Vol XXXIV (II) ◽  
pp. 305-311 ◽  
Author(s):  
M. G. Woldring ◽  
A. Bakker ◽  
H. Doorenbos
Keyword(s):  
Thyroid Function ◽  
Incubation Time ◽  
Clinical Results ◽  
Human Erythrocytes ◽  
Red Cell ◽  
Clinical Value ◽  
Blood Samples ◽  
In Vitro Uptake

ABSTRACT The red cell triiodothyronine uptake technique as used in our hospital is described. Incubation time is of almost no importance. The temperature during incubation should be 37° C. Further improvement of the technique is obtained when all blood samples are brought up to 40 % haematocrit prior to incubation. Clinical results are discussed. It is yet too early to give a definite assessment of its clinical value, but it is definitely superior to the measurement of the BMR.

A cool modality to restore sinus rhythm

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
O Yasin ◽  
A Sugrue ◽  
M Van Zyl ◽  
A Ladejobi ◽  
J Tri ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Body Temperature ◽  
Sinus Rhythm ◽  
Animal Experiments ◽  
Funding Source ◽  
Atrial Pacing ◽  
Exact Test ◽  
Chi Squared ◽  
Cool Device ◽  
Atrial Defibrillation

Abstract Background Slowing electrical conduction by cooling the myocardium can be used for defibrillation. We previously demonstrated the efficacy of a small cold device placed in oblique sinus (OS) in terminating atrial fibrillation (AF). However, the parameters needed to achieve effective atrial defibrillation are unknown. Purpose Assess effect of the size of cooled myocardium on frequency of AF termination in acute canine animal models. Methods Sternotomy was performed under general anesthesia in 10 acute canine experiments. AF was induced using rapid atrial pacing and intra-myocardial epinephrine and acetylcholine injections. Once AF sustained for at least 30s, either a cool (7–9°C) or placebo (body temperature) device was placed in the OS. Four device sizes were tested; ½X½, ¾X¾, and 1X1 inch devices and two ¾X¾ inch devices placed side by side simultaneously. Time to AF termination was recorded. Chi-squared or Fisher's exact test were used to compare the frequency of arrhythmia termination with cooling versus placebo. Results A total of 166 applications were performed (89 cool vs 77 placebo) in 10 animal experiments. Overall, AF terminated in 82% of the cooling applications vs. 67.5% of placebo (P=0.03, Figure 1). For the ½X½ inch device 88% of cold applications restored sinus rhythm vs. 63.6% for placebo (P=0.05). The frequency of sinus restoration for cold ¾X¾, 1X1 and two ¾X¾ side by side devices was 86.7%, 83.3% and 70% respectively. Time to sinus restoration when achieved was within three minutes was also not significantly changed. Conclusion Placing a cool device in the oblique sinus can terminate AF and efficacy is not affected by the size of device. Funding Acknowledgement Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): MediCool Technologies

scholarly journals Preclinical Testing of Radiopharmaceuticals for the Detection and Characterization of Osteomyelitis: Experiences from a Porcine Model

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4221
Author(s):  
Aage Kristian Olsen Alstrup ◽  
Svend Borup Jensen ◽  
Ole Lerberg Nielsen ◽  
Lars Jødal ◽  
Pia Afzelius
Keyword(s):  
Animal Model ◽  
Animal Models ◽  
Porcine Model ◽  
Animal Experiments ◽  
Radioactive Tracers ◽  
The Individual ◽  
Selection Of

The development of new and better radioactive tracers capable of detecting and characterizing osteomyelitis is an ongoing process, mainly because available tracers lack selectivity towards osteomyelitis. An integrated part of developing new tracers is the performance of in vivo tests using appropriate animal models. The available animal models for osteomyelitis are also far from ideal. Therefore, developing improved animal osteomyelitis models is as important as developing new radioactive tracers. We recently published a review on radioactive tracers. In this review, we only present and discuss osteomyelitis models. Three ethical aspects (3R) are essential when exposing experimental animals to infections. Thus, we should perform experiments in vitro rather than in vivo (Replacement), use as few animals as possible (Reduction), and impose as little pain on the animal as possible (Refinement). The gain for humans should by far exceed the disadvantages for the individual experimental animal. To this end, the translational value of animal experiments is crucial. We therefore need a robust and well-characterized animal model to evaluate new osteomyelitis tracers to be sure that unpredicted variation in the animal model does not lead to a misinterpretation of the tracer behavior. In this review, we focus on how the development of radioactive tracers relies heavily on the selection of a reliable animal model, and we base the discussions on our own experience with a porcine model.

scholarly journals Altered left atrial 4D flow characteristics in patients with paroxysmal atrial fibrillation in the absence of apparent remodeling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmet Demirkiran ◽  
Raquel P. Amier ◽  
Mark B. M. Hofman ◽  
Rob J. van der Geest ◽  
Lourens F. H. J. Robbers ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Sinus Rhythm ◽  
Flow Velocity ◽  
Paroxysmal Atrial Fibrillation ◽  
Left Atrial ◽  
Peak Flow ◽  
Thrombus Formation ◽  
Clinical Value ◽  
4D Flow ◽  
Ssfp Cine

AbstractThe pathophysiology behind thrombus formation in paroxysmal atrial fibrillation (AF) patients is very complex. This can be due to left atrial (LA) flow changes, remodeling, or both. We investigated differences for cardiovascular magnetic resonance (CMR)-derived LA 4D flow and remodeling characteristics between paroxysmal AF patients and patients without cardiac disease. In this proof-of-concept study, the 4D flow data were acquired in 10 patients with paroxysmal AF (age = 61 ± 8 years) and 5 age/gender matched controls (age = 56 ± 1 years) during sinus rhythm. The following LA and LA appendage flow parameters were obtained: flow velocity (mean, peak), stasis defined as the relative volume with velocities < 10 cm/s, and kinetic energy (KE). Furthermore, LA global strain values were derived from b-SSFP cine images using dedicated CMR feature-tracking software. Even in sinus rhythm, LA mean and peak flow velocities over the entire cardiac cycle were significantly lower in paroxysmal AF patients compared to controls [(13.1 ± 2.4 cm/s vs. 16.7 ± 2.1 cm/s, p = 0.01) and (19.3 ± 4.7 cm/s vs. 26.8 ± 5.5 cm/s, p = 0.02), respectively]. Moreover, paroxysmal AF patients expressed more stasis of blood than controls both in the LA (43.2 ± 10.8% vs. 27.8 ± 7.9%, p = 0.01) and in the LA appendage (73.3 ± 5.7% vs. 52.8 ± 16.2%, p = 0.04). With respect to energetics, paroxysmal AF patients demonstrated lower mean and peak KE values (indexed to maximum LA volume) than controls. No significant differences were observed for LA volume, function, and strain parameters between the groups. Global LA flow dynamics in paroxysmal AF patients appear to be impaired including mean/peak flow velocity, stasis fraction, and KE, partly independent of LA remodeling. This pathophysiological flow pattern may be of clinical value to explain the increased incidence of thromboembolic events in paroxysmal AF patients, in the absence of actual AF or LA remodeling.

ASSA13-06-2 Characterization of Small-Conductance Ca2+-Activated K+Channels in Patients with Chronic Atrial Fibrillation

Heart ◽  
2013 ◽  
Vol 99 (Suppl 1) ◽  
pp. A33.2-A33
Author(s):  
Li Miao-ling ◽  
Li Tao ◽  
Lan Huan ◽  
Mao Liang ◽  
Ou Xian-hong ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Chronic Atrial Fibrillation ◽  
K Channels ◽  
Small Conductance

Cough suppressants

1965 ◽  
Vol 3 (12) ◽  
pp. 47-48
Keyword(s):  
Experimental Method ◽  
Animal Experiments ◽  
Clinical Value

Cough is at once a necessary function and an unwanted symptom. Whether preparations intended to prevent it or relieve its discomfort are clinically effective in safe doses is uncertain. This is due to difficulties in experimental method. Neither animal experiments nor experiments with artificially induced cough in man can reliably predict the clinical value of an antitussive,1 2 and patients with established cough are poor witnesses of its frequency or severity.1 3

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