Publications by authors named "Gunther Van Loon"
Article Synopsis
- The study focused on identifying diseases and risk factors leading to death in hospitalized neonatal foals.
- Sepsis was the most common disease found, significantly increasing mortality risk, with a case fatality rate of 33.3%.
- Key risk factors included comatose state, high L-lactate levels, and increased serum amyloid A, which could help veterinarians make informed decisions during treatment.
Article Synopsis
- The study investigated the use of ablation index-guided radiofrequency catheter ablation (RFCA) to treat atrial tachycardia (AT) in horses, focusing on the caudal vena cava, a common problem area.
- Ten horses with sustained AT underwent three-dimensional electro-anatomical mapping and RFCA, achieving successful isolation of the caudal vena cava and restoring normal heart rhythm in all cases.
- Follow-up showed no recurrence of AT in the horses studied, indicating the method's effectiveness and feasibility for long-term treatment.
Article Synopsis
- The study investigates how renal artery stenosis (RAS) affects blood flow and renin release in a pig model, particularly when there is significant stenosis on the opposite kidney side.
- Researchers measured kidney pressure and blood flow while gradually blocking the renal artery to understand how these changes impact renin secretion.
- Findings revealed that a 25% reduction in renal perfusion pressure significantly reduced blood flow and increased renin release, especially when there was already significant stenosis in the contralateral kidney.
Background: MicroRNA (miRNA) has previously been used as a biomarker for cardiac disease in humans and dogs, however, studies in horses are not yet available.
Objectives: To determine if adult horses with moderate or severe mitral valve regurgitation have a different serum miRNA expression profile compared to healthy controls.
Study Design: Retrospective cross-sectional.
Sustained atrial tachycardia at an atrial rate of 191/min on the surface ECG was detected in a 6-year-old Warmblood mare. The vectorcardiogram obtained from a 12-lead ECG suggested a caudo-dorsal right atrial origin of the arrhythmia. Impedance-based three-dimensional electro-anatomical mapping, using the EnSite™ Precision Cardiac Mapping System revealed a clockwise macro-reentry around a line of conduction block in the caudomedial right atrium.
View Article and Find Full Text PDFRadiofrequency ablation is a promising technique for arrhythmia treatment in horses. Due to the thicker myocardial wall and higher blood flow in horses, it is unknown if conventional radiofrequency settings used in human medicine can be extrapolated to horses. The study aim is to describe the effect of ablation settings on lesion dimensions in equine myocardium.
View Article and Find Full Text PDFBackground: Reliable ECGs are crucial for diagnosing arrhythmias, yet a lack of standardization impedes arrhythmia diagnosis and treatment in horses.
Objectives: To objectively determine an optimal position of Einthoven's triangle for ECG recordings in horses at rest, which can form the basis for standardized ECG recording and improve diagnosis and treatment of arrhythmias.
Animals: The study involved 72 healthy, warmblood horses aged between 3 and 20 years.
Article Synopsis
- The study focuses on improving arrhythmia characterization in horses through minimally invasive catheterizations, which have been infrequently explored due to difficulties in imaging and guiding catheters.
- Researchers hypothesized that multiple electrophysiology catheters could be positioned simultaneously in the horse's heart using transthoracic echocardiography for guidance.
- Results showed successful catheter placements in the right heart and left ventricle but faced challenges in the left atrium and pulmonary veins; however, this method offers a promising alternative for minimally invasive arrhythmia diagnoses without relying on 3D mapping systems.
Background: Cardiac catheterizations in horses are mainly performed in the right heart, as access to the left heart traditionally requires an arterial approach. Transseptal puncture (TSP) has been adapted for horses but data on follow-up and closure of the iatrogenic atrial septal defect (iASD) are lacking.
Hypothesis/objectives: To perform TSP and assess postoperative complications and iASD closure over a minimum of 4 weeks.
Article Synopsis
- * They studied blood samples from 263 horses, including those with AM, healthy horses grazing together, and others with colic, and found some key differences in their blood that could help identify AM.
- * The researchers discovered that younger geldings (castrated male horses) had a lower risk of getting AM, and a specific type of blood marker could help tell if a horse with AM would survive.
Article Synopsis
- Transseptal puncture (TSP) was successfully performed in a study involving 18 horses, aiming to develop a zero fluoroscopy technique for accessing the left atrium through the jugular vein and transhepatic approaches.
- Intracardiac echocardiography was crucial for guiding the puncture process, with a high success rate in achieving the procedure, but potential complications included atrial arrhythmias in some horses.
- The study noted limitations, such as the sequential testing of different approaches and lack of randomization, suggesting further research is needed to refine the technique.
Background: Three-dimensional electro-anatomical mapping, previously performed in horses with atrial arrhythmias, has demonstrated the medial region of the caudal vena cava (CaVC), 1-8 cm caudal to the fossa ovalis, as an anatomical predilection site for atrial tachycardia associated with areas of slow conduction and conduction block. Slow conduction has also been recorded in the cranial vena cava (CrVC).
Objectives: To investigate the morphological characteristics of the myocardial sleeves (MS) in the CaVC and CrVC, in order to identify a potential substrate of right sided atrial arrhythmias.
Background: Echocardiographic measurements are important prognostic indicators but might be influenced by heart rate and blood pressure. This is particularly important when comparing repeated examinations.
Hypothesis: To determine the effect of physiological stress at mildly increased heart rates and pharmacological challenge using IV administration of N-butylscopolammonium bromide and metamizol sodium on heart rate, blood pressure, and echocardiographic measurements.
Background: Recently, treatment of equine atrial tachycardia by three-dimensional electro-anatomical mapping (3D EAM) and radiofrequency catheter ablation (RFCA) has been described. Myocardial sleeves in the caudal vena cava and pulmonary veins are a potential trigger for initiation and perpetuation of atrial tachycardia and atrial fibrillation in the horse. Isolation of these myocardial sleeves by RFCA may be an effective treatment for these arrhythmias.
View Article and Find Full Text PDFRationale And Objectives: To investigate the renal pressure-flow relationship and its relation to renin release, because the renal perfusion pressure below which renal flow starts to decline and renin secretion is upregulated is unclear.
Materials And Methods: A porcine model of graded unilateral renal artery stenosis was created. The severity of the stenosis was expressed as the ratio between distal renal pressure (P) and aortic pressure (P).
We describe the diagnosis and treatment of an atrioventricular accessory pathway (AP) in a horse using 3-dimensional electro-anatomical mapping (3D EAM) and radiofrequency catheter ablation (RFCA). During routine evaluation of the horse, intermittent ventricular pre-excitation was identified on the ECG, characterized by a short PQ interval and abnormal QRS morphology. A right cranial location of the AP was suspected from the 12-lead ECG and vectorcardiography.
View Article and Find Full Text PDFThe ductus arteriosus (DA) and foramen ovale (FO), including the septum primum (SP) and septum secundum (SS), are important structures in fetal circulation and are unexplored in neonatal equids. The objective of this study is to describe echocardiographic characteristics in a hospital-based population of neonatal foals. On days 2, 5 and 10 after parturition, cardiac ultrasound was performed, and clinical data were collected in healthy and diseased Warmblood foals.
View Article and Find Full Text PDFArticle Synopsis
- Atrial tachycardia (AT) in horses can be difficult to treat with high recurrence rates, but 3D electro-anatomical mapping may help in identifying the underlying causes for more effective treatment.
- The study involved reviewing cases of 9 horses with sustained AT, finding that most cases originated from specific localized areas in the heart.
- Successful treatment using radiofrequency catheter ablation led to significant improvements, with a majority of the horses remaining free of AT recurrence at follow-up.
This case report describes the 2-dimensional transthoracic (2D-TTE), 3-dimensional transthoracic (3D-TTE) and intracardiac echocardiographic (ICE) characterization of the fossa ovalis region in 2 horses. The first case was presented for poor performance and showed an anechoic zone in the interatrial septum on 2D-TTE. Based on 3D-TTE a deepened fossa ovalis could be identified and using ICE the presence of an interatrial shunt could be excluded.
View Article and Find Full Text PDFArticle Synopsis
- The study aimed to investigate if vectorcardiography (VCG) can differentiate the anatomical origin of pacing-induced ventricular premature depolarizations (VPDs) in horses, given the inconsistent results from previous studies using 12-lead electrocardiograms (ECG).
- Seven horses were studied under general anesthesia, where researchers recorded a 12-lead ECG during various pacing locations in the heart, using advanced mapping techniques to guide catheter placement.
- The findings revealed significant differences in electrical axes for VPDs depending on the pacing location and rhythm, indicating that VCG could effectively identify the anatomical origins of ventricular ectopy in horses.
Article Synopsis
- The study investigates the anatomical origins of atrial premature depolarizations (APDs) in horses using a combination of 12-lead ECG and vectorcardiography (VCG).
- The researchers conducted paced trials in seven horses under anesthesia, targeting specific areas of the heart while employing advanced mapping techniques.
- Results showed significant differences in electrical axis directions between various pacing sites and sinus rhythm, highlighting the potential of VCG in locating the origins of atrial irregularities.
Background: Transvenous electrical cardioversion (TVEC) is 1 of the main treatment options for atrial fibrillation (AF) in horses. Large-scale studies on factors affecting success and prognosis have primarily been performed in Standardbred populations.
Hypothesis/objectives: To determine factors affecting cardioversion success, cardioversion difficulty and recurrence in a predominant Warmblood study sample.
Background: The recurrence rate of atrial fibrillation (AF) in horses after cardioversion to sinus rhythm (SR) is relatively high. Atrial fibrillatory rate (AFR) derived from surface ECG is considered a biomarker for electrical remodelling and could potentially be used for the prediction of successful AF cardioversion and AF recurrence.
Objectives: Evaluate if AFR was associated with successful treatment and could predict AF recurrence in horses.
Article Synopsis
- Researchers implanted advanced rate-adaptive pacemakers with accelerometer and remote monitoring in miniature donkeys suffering from severe heart block and fainting episodes.
- The testing of different programming modes showed that the pacemaker's closed loop stimulation (CLS) effectively adjusted pacing rates in response to the donkeys' heart activity, mimicking normal physiological responses.
- The remote monitoring feature enabled daily wireless data transmission to a secure server, facilitating continuous oversight of the donkeys' heart health and prompt detection of any issues from afar.