Normal Electrocardiographic Pattern in Conscious Healthy Domestic Geese (Anser anser)

The aim of this study was to describe the reference intervals of electrocardiographic patterns and values in conscious healthy domestic geese (Anser anser). Standard bipolar and augmented unipolar limb lead electrocardiograms with a direct writing electrocardiograph were recorded in 14 domestic geese. The durations of PR interval, QRS complex, ST and QT intervals, the net of the QRS complex, and the P and T amplitudes were determined at 50 mm/s and at 1 cm = 1 mV. The polarity waveform was examined. The mean electrical axis in the frontal plane was determined in leads II and III. Data are expressed as means and standard deviations. The mean (SD) heart rate was 153.8 (22.4) beats/min. The QRS complex was mainly negative in leads II and III; it was positive in the augmented vector right, augmented vector left, and augmented vector foot leads. The T wave was positive in leads II, III, and the augmented vector foot lead and was negative in the augmented vector right and left leads. The mean electrical axis ranged between -30° to -140°. Electrocardiogram recordings were well tolerated by the geese. The reference intervals provided here can be used to assist in the interpretation of electrocardiographic patterns in geese.

High heart rate associated early repolarization causes J-waves in both zebra finch and mouse

High heart rates are a feature of small endothermic—or warm‐blooded—mammals and birds. In small mammals, the QT interval is short, and local ventricular recordings reveal early repolarization that coincides with the J‐wave on the ECG, a positive deflection following the QRS complex. Early repolarization contributes to short QT‐intervals thereby enabling brief cardiac cycles and high heart rates. We therefore hypothesized high hearts rates associate with early repolarization and J‐waves on the ECG of endothermic birds. We tested this hypothesis by comparing isolated hearts of zebra finches and mice and recorded pseudo‐ECGs and optical action potentials (zebra finch, n = 8; mouse, n = 8). In both species, heart rate exceeded 300 beats per min, and total ventricular activation was fast (QRS < 10 ms). Ventricular activation progressed from the left to the right ventricle in zebra finch, whereas it progressed from apex‐to‐base in mouse. In both species, the early repolarization front followed the activation front, causing a positive J‐wave in the pseudo‐ECG. Inhibition of early repolarization by 4‐aminopyridine reduced J‐wave amplitude in both species. Action potential duration was similar between ventricles in zebra finch, whereas in mouse the left ventricular action potential was longer. Accordingly, late repolarization had opposite directions in zebra finch (left‐right) and mouse (right‐left). This caused a similar direction for the zebra finch J‐wave and T‐wave, whereas in the mouse they were discordant. Our findings demonstrate that early repolarization and the associated J‐wave may have evolved by convergence in association with high heart rates.

Comparative Quantitative Studies on the Microvasculature of the Heart of a Highly Selected Meat-Type and a Wild-Type Turkey Line

In this study the macroscopic and microscopic structure of the heart of a fast growing, meat-type turkey line (British United turkeys BUT Big 6) and a wild-type turkey line (Canadian Wild turkey) were compared. At 8 and 16 weeks of age, 10 birds of each genotype and sex were sampled. The body mass and heart mass of the meat-type turkey both increased at a faster rate than those of the wild-type turkey. However in both turkey lines, the relative heart mass decreased slightly with age, the decrease was statistically significant only in the male turkeys. Furthermore meat-type turkeys had a significantly (p < 0.01) lower relative heart mass and relative thickness of the left ventricle compared to the wild-type turkeys of the same age. The wild-type turkeys showed no significant change in the size of cardiomyocytes (cross sectional area and diameter) from 8 weeks to 16 weeks. In contrast, the size of cardiomyocytes increased significantly (p < 0.001) with age in the meat-type turkeys. The number of capillaries in the left ventricular wall increased significantly (p < 0.001) in wild-type turkeys from 2351 per mm² at the age of 8 weeks to 2843 per mm² at 16 weeks. However, in the meat-type turkeys there were no significant changes, capillary numbers being 2989 per mm² at age 8 weeks and 2915 per mm² at age 16 weeks. Correspondingly the area occupied by capillaries in the myocardium increased in wild-type turkeys from 8.59% at the age of 8 weeks to 9.15% at 16 weeks, whereas in meat-type turkeys this area decreased from 10.4% at 8 weeks to 9.95% at 16 weeks. Our results indicate a mismatch in development between body mass and heart mass and a compromised cardiac capillary density and architecture in the meat-type turkeys in comparison to the wild-type turkeys.

Analysis of the Normal Electrocardiogram in Wild Rooks ( Corvus frugilegus )

To describe the normal electrocardiographic (ECG) patterns and values in unanesthetized rooks ( Corvus frugilegus ), standard bipolar (I, II, and III) and augmented unipolar limb (aVR, aVL, and aVF) lead ECGs were recorded from 10 clinically healthy wild rooks. Wave forms were analyzed in all leads at 50 mm/s and at 10 mm = 1 mV to determine PR, QRS, ST, and QT durations; the net QRS complex; and P and T amplitudes. The polarity of each waveform was tabulated in all leads. The mean electrical axis (MEA) for the frontal plane was counted by using leads II and III. The mean heart rate was 340 ± 18 beats/min. The P wave was mainly positive in the most leads. The dominant pattern of waveforms of the QRS complexes was QS in leads II, III, and aVF, whereas in leads aVR and aVL, the patterns were rS and R, respectively. The T wave was positive in leads II, III, aVF, and aVL and negative in lead aVR. The mean of the heart MEA was -93 ± 2.2. Interpretation of the ECG values and patterns in rooks may facilitate a better realization of ECG changes of abnormalities in this species.

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.

Normal electrocardiogram patterns and values in Muscovy ducks (Cairina moschata)

To describe normal electrocardiographic parameters in conscious Muscovy ducks (Cairina moschata), standard bipolar (I, II, and III) and augmented unipolar limb (aVR, aVL, and aVF) lead electrocardiograms were recorded in 10 clinically healthy birds. Wave forms were analyzed in all leads at 50 mm/s and at 10 mm= 1 mV to determine PR, QRS, ST, QT durations; the net QRS complex; and P and T amplitudes. The polarity of each waveform was tabulated in all leads. The mean electrical axis (MEA) for the frontal plane was calculated by using leads II and III. The mean (SEM) heart rate calculated from lead II was 146.6 - 6.8 beats/min. The P wave was predominantly positive in all leads. The dominant pattern of waveforms of the QRS complexes was rS in leads II, III, and aVF, whereas, in leads aVR, and aVL, the pattern was R. The T wave was positive in leads II, III, and aVF and was negative in leads aVR and aVL. The mean (SEM) of the heart MEA was -91.2 2 1.8. The electrocardiographic values and patterns tabulated in these clinically normal Muscovy ducks should provide a means of comparison to aid in the diagnosis of pathologic abnormalities in this species.

Normal electrocardiogram of the laughing dove (Spilopelia senegalensis)

The aim of this study was to describe the normal electrocardiographic patterns and values in conscious laughing dove (Spilopelia senegalensis). The standard bipolar (I, II, and III) and augmented unipolar limb (aVR, aVL, and aVF) leads' electrocardiographs were recorded in 10 clinically healthy laughing doves. The wave forms were analyzed in all leads at 50 mm/sec and at 10 mm = 1 mV to determine PR, QRS, ST, and QT durations, the net QRS complex, and P and T amplitudes. The polarity of each waveform was tabulated in all leads. The mean electrical axis (MEA) for the frontal plane was calculated using standard bipolar leads II and III. The mean heart rate (calculated from the lead II) was 357 +/- 12.5 beats/min. The P wave was positive in all leads except for the aVR lead. The dominant pattern of waveforms for the QRS complexes was rS in leads II, III, aVR, and aVF, whereas in leads I and aVL, the patterns were R and Rs, respectively. The T wave was positive in leads II, III, aVF and negative in leads I, aVR, and aVL. The average value of the heart MEA was -89.7 +/- 1.30 degrees. The electrocardiogram values and patterns tabulated in these clinically normal laughing doves provide a means of comparison to aid in the diagnosis of pathologic abnormalities in this species.

Electrocardiogram analysis of the normal unanesthetized green peafowl (Pavo muticus)

The aim of this study was to describe normal electrocardiogram (ECG) patterns and values in unanesthetized green peafowl (Pavo muticus). The standard bipolar and augmented unipolar limb leads ECGs were recorded in the birds. The waveforms were analyzed in all leads at 50 mm/sec and at 10 mm = 1 mV to determine P, PR (segment and interval), QRS, ST, QT durations, P, net QRS complex and T amplitudes. The polarity of each waveform was tabulated in all leads. The mean electrical axis (MEA) for the frontal plane was calculated using leads II and III. The mean heart rates were calculated from lead II that was 257.5 ± 5.33 beats/min. The P wave was dominantly positive in all leads. The dominant pattern of waveforms of the QRS complexes were QS in leads II, III, and aVF. In leads I, aVR and aVL, the R pattern was dominant. The T wave was almost positive in leads I, II, and aVF. The average value of the heart MEA was -96.75 ± 3.31°. Description of normal ECG parameters will facilitate a better realizing of ECG changes of unhealthy green peafowls.

The normal electrocardiogram of conscious golden eagles (Aquila chrysaetos)

The aim of this study was to describe the normal electrocardiographic patterns and values in conscious golden eagles (Aquila chrysaetos). The standard bipolar and augmented unipolar limb leads' electrocardiograms were recorded in the golden eagles. The waveforms were analyzed in all leads at 50 mm/sec and at 10 mm = 1 mV to determine P, PR (segment and interval), QRS, ST, and QT durations and P, net QRS complex, and T amplitudes. The polarity of each waveform was tabulated in all leads. The mean electrical axis for the frontal plane was calculated using standard bipolar leads II and III. The mean heart rate was 346.7 +/- 14.29 beats/min. The P wave was predominantly positive in standard bipolar leads I and II and augmented unipolar limb leads aVL and aVF. The dominant pattern ofwaveforms of the QRS complexes were QS in leads I, II, III, and aVF, whereas in leads aVR and aVL, the pattern was always R. The T wave was slightly positive in leads I, II, and aVF. The average value of the heart mean electrical axis was -85.9 +/- 7.50 degrees. Establishment of normal electrocardiogram values will facilitate a better understanding of electrocardiographic changes seen in many avian diseases.

Critical care monitoring

Small mammals and birds present unique challenges for the clinician in treatment of life-threatening conditions. Numerous books have been written on shock, critical care, and cardiopulmonary resuscitation in small animals. The basic protocols can be adapted for use in small mammals and birds. A general review of the pathophysiology of shock is important to the understanding of fluid therapy plans discussed in this article. Using the general principles of cardiopulmonary-cerebral resuscitation in small animals, protocols are discussed for use in birds and small mammals.

Depolarisation and repolarisation sequences of ventricular epicardium in chickens (Gallus gallus domesticus)

Activation and recovery sequences were mapped by means of 64-channel synchronous recording of extracellular potentials on ventricular epicardium in chickens. Ventricular epicardium was depolarized due to multiple breakthroughs. The recovery of ventricular epicardium occurs from the apex to the base of heart and does not repeat the activation sequence. Gradients of repolarisation exist over the ventricular epicardium in birds. Repolarisation pattern of ventricular epicardium depends primarily on intrinsic spatial heterogeneities of ARIs over epicardium.

The role of sodium ions in the pathogenesis of skeletal muscle damage in broiler chickens

The effect of sodium ions (Na+) on calcium (Ca2+)-mediated muscle damage in broiler chickens was investigated using an in vitro muscle preparation. Muscle Ca2+ accumulation was determined by 45Ca2+ uptake. Muscle damage was assessed by measurement of the efflux of the intracellular enzyme creatine kinase (CK) into the incubation medium. Loading muscle cells with Na+ by means of the sodium ionophore monensin led to concentration-dependent (25 to 200 microM) increases in 45Ca2+ uptakes and corresponding and proportional CK losses. The greatest responses occurred at 100 microM ionophore or greater, reflected in a 49% increase (P < 0.05) in 45Ca2+ uptake and an associated 140%-fold increase (P < 0.001) in CK efflux. Inhibition of muscle Na+/K+-ATPase activity with ouabain (2 mM) induced a 56% increase in 45Ca2+ uptake and a 60%-fold increase (P < 0.001) in total CK loss. The combined use of ionophore and ouabain resulted in 90 and 130%-fold elevations in 45Ca2+ uptake and CK loss, respectively. In monensin-treated muscles, inhibition of external Ca2+ influx from the incubation medium by chelation with 1,2 bis(2-aminophenoxy)ethane-N,N,N',N' tetracetic acid (5 mM) markedly reduced 45Ca2+ uptake (38%: P < 0.05) but increased CK release by 85% (P < 0.001). The results demonstrate that initial elevations in muscle Na+ can facilitate increases in muscle Ca2+ and lead to alterations in muscle cell membrane integrity and CK loss. The Na+-induced increases in myocellular Ca2+ may be mediated via direct extracellular Ca2+ entry or redistribution from internal Ca2+ stores. It is proposed that in order to reduce or prevent myopathies in poultry, exposure to conditions that may lead to elevations in muscle Na+ (e.g., increased muscle activity and stress or accidental ionophore toxicosis) should be avoided. The findings of this study have implications for management strategies of bird welfare, muscle pathology, and product quality.

Heart growth in broilers

1. Morphological development of the heart in fast-growing, meat-type fowl of both sexes was studied. 2. In 4 experiments, fowl were weighed, killed and hearts were dissected at 0, 20, 34, and 48th d of age. Heart weight (HW), length (HL), diameter (HD), and thickness of the right ventricular wall (RVW) and left ventricular wall (LVW) were determined. 3. This is the first description of sexual dimorphic differences in the heart of fowl. 4. Results indicate that males have greater HW, HL, and LVW thickness than females. However, thickness of the RVW during the embryonic period, as indicated by thickness of the RVW at hatching in females, exceeds that of males.