Electrocardiographic observation on spontaneously occurring arrhythmias in chickens

Cardiovascular Diseases in Pet Birds: Therapeutic Options and Challenges

Cardiovascular disease, including congestive heart failure, pericardial disease, and atherosclerosis, is becoming increasingly better recognized in companion birds. A wide range of medications is available to treat these conditions, including diuretics, vasodilators, positive and negative inotropes, antiarrhythmic agents, and pentoxifylline. This review systematically discusses each of these drug classes and their potential applications in avian species. Although treatment approaches remain largely empirical and extrapolated from small animal and human medicine, the management strategies presented here have the potential to both maintain quality of life and extend survival time for the avian cardiac patient.

Cardiovascular Drugs in Avian, Small Mammal, and Reptile Medicine

Cardiovascular disease, including congestive heart failure, pericardial disease, and atherosclerosis, is becoming increasingly better recognized in companion birds, small mammals, and reptiles. A wide range of medications is available to treat these conditions, including diuretics, vasodilators, positive and negative inotropes, antiarrhythmic agents, and pentoxifylline. This review systematically discusses each of these drug classes and their potential applications in exotic species. Although treatment approaches remain largely empirical and extrapolated from small animal and human medicine, the management strategies presented here have the potential to both maintain quality of life and extend survival time for the exotic cardiac patient.

Emergencies and Critical Care of Commonly Kept Fowl

Fowl are birds belonging to one of the 2 biological orders, the game fowl or land fowl (Galliformes) and the waterfowl (Anseriformes). Studies of anatomic and molecular similarities suggest these two groups are close evolutionary relatives. Multiple fowl species have a long history of domestication. Fowl are considered food-producing animals in most countries and clinicians should follow legislation regarding reportable diseases and antibiotic use, even if they are pets. This article reviews aspects of emergency care for most commonly kept fowl, including triage, patient assessment, diagnostic procedures, supportive care, short-term hospitalization, and common emergency presentations.

Left ventricular myocardal activation under ventricular paced beats in chickens Gallus gallus domesticus

The aim of the study was to advance our knowledge regarding the activation process of the ventricular myocardium in birds in which Purkinje fibres penetrate into the ventricular wall to reach the epicardium. A depolarization pattern of the left ventricular free wall was studied in chickens (Gallus gallus) during ventricular paced beats. Duration of the activation process of the left ventricular free wall is significantly increased during ventricular ectopic excitation as compared with sinus rhythm. Its lowest increase occurs during subendocardial pacing of the middle part of the left ventricle, but its greatest increase is observed during subepicardial pacing of the left ventricular base. Multifocality and mosaicity of depolarization of the left ventricular free wall myocardium in chicken are expressed in a considerably less degree during ventricular paced beats in comparison with sinus rhythm. During ventricular paced beats, excitation of the left ventricular free wall is mostly due to the successive spreading of the depolarization wave from pacing sites.

Intermittent biotelemetric monitoring of electrocardiograms and temperature in male broilers at risk for sudden death syndrome

Biotelemetry was used to acquire electrocardiograms (ECG) and temperature measurements in a study of male broilers at risk for sudden death syndrome (SDS), a fatal condition that may have underlying cardiovascular mechanisms. Day-old (Day 1) Arbor Acres x Arbor Acres male chicks were randomly assigned to two different diets: control (Diet A) and one that contained elements that contribute to SDS (Diet B). The heaviest birds in each group on Day 13 underwent surgery on Day 15 to have transmitters with temperature sensors and ECG electrodes implanted. After surgery, three controls and three implanted birds from each diet group were kept in individual cages and exposed to 23 h of light and 1 h of darkness during each 24-h cycle. Implantation did not affect weight gain between Days 13 and 22 (P = 0.396). Temperature measurements and 1-min ECG were taken every 15 min. Heart rate and heart rate variability were measured from three 2-s segments in two dark and two light period samples during Days 17 to 19. Diet B decreased weight gain (P = 0.045), lowered heart rate (P < 0.0001), and increased internal temperature (P < 0.0001). Heart rate variability was lower during dark versus light periods (P = 0.004), which indicates that the birds rested during the dark periods, but was not affected by diet (P = 0.651). Thus, biotelemetry provided a useful method for intermittent physiological monitoring of poultry on different diets and under changing environmental conditions.

Ventricular preexcitation sensitive to flecainide in late stage chick embryo ECGs: 2,3,7,8-tetrachlorodibenzo-p-dioxin impairs inotropic but not chronotropic or dromotropic responses to isoproterenol and confers resistance to flecainide

ECGs free of movement artefacts were obtained without anesthesia in 16- to 18-day-old chick embryos close to hatching and used to study the effect of the environmental toxin 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) on cardiac rhythm and conduction. The ECGs of normal late stage chick embryos exhibited short PR intervals, frequent nonisoelectric PR segments, delta waves, and inverted T waves. Those ECG characteristics are found in patients with the Wolff-Parkinson-White syndrome (WPW) in which they reflect ventricular preexcitation associated with the use of accessory conduction pathways and arrhythmias. Isoproterenol (30 microg/egg) did not alter the ECG preexcitation characteristics. Flecainide, a sodium channel blocker used clinically to suppress WPW accessory pathway activity, at 0.5 to 5 mg per egg diminished the preexcitation and caused atrioventricular (AV) block, supporting the use of accessory pathways together with AV-nodal conduction in normal late stage chick embryos. The findings challenge the dogma that accessory pathways are entirely replaced by AV conduction pathways in late fetal development. TCDD, at 1-2 nmol per egg for 48 h, did not affect heart rate, the increase in heart rate by isoproterenol, or the ECG characteristics, suggesting that short-term TCDD treatment did not affect sinus node function or cardiac conduction. The latter results taken together with prior findings indicate that TCDD differentially impairs the inotropic and lusitropic effects but not the chronotropic or dromotropic effects of isoproterenol. In TCDD-treated embryos, flecainide, tested at 5 mg per egg, caused much less inhibition of preexcitation or production of AV block than in the untreated or solvent-treated controls. The resistance to flecainide represents a new TCDD effect consistent with the reported increase of cardiac myocyte [Ca(2+)](i) by TCDD treatment.