case_images: PMC11769261_01
case_images: Six-lead electrocardiography recording from a 3-year-old, 27 kg mixed-breed male Labrador indicating complete atrio-ventricular dissociation with narrow QRS complexes and a normal mean electrical axis in the frontal plane. The red arrowheads represent the P-waves hidden in the QRS, ST segment, or T-wave; note that the PQ interval is variable, suggesting complete dissociation between the sinus and the ventricular rhythm; P:p-wave; R:QRS complex; calibration: 50 mm/sec and 10 mm/mV.
case_images: vetsci-12-00063-g001.jpg
case_images: PMC11769261_01_vetsci-12-00063-g001.jpg
case_images: vetsci-12-00063-f001
case_images: Six-lead ECG revealed a complete atrio-ventricular block with an atrial rate of 140 bpm and a ventricular rate of 60 bpm (Figure 1).
case_images: Adrenal gland ultrasound images of a dog, showing the longitudinal axis. On the left (A) is the left adrenal gland (LAG), with a diameter of 3 mm, corresponding to an ultrasound change consistent with HA; one the right (B) is the right adrenal gland (RAG), with a normal diameter of 5.6 mm.
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case_images: PMC11769261_01_vetsci-12-00063-g002.jpg
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case_images: The left adrenal gland had a normal shape and echogenicity, with a diameter of 3 mm on the longitudinal axis at the caudal pole (normal values: 5.3-6.3 mm) (Figure 2).
case_images: Six-lead electrocardiography results for the same dog after serum potassium concentration normalization: note the presence of a sinus rhythm with a mean heart rate of 110 bpm and constant PQ intervals with a duration of 100 msec; calibration: 50 mm/sec and 10 mm/mV.
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case_images: PMC11769261_01_vetsci-12-00063-g003.jpg
case_images: vetsci-12-00063-f003
case_images: Twenty-four hours later, the ECG was repeated, revealing a sinus rhythm with normal atrio-ventricular conduction, with a mean HR over 5 min of 110 bpm (Figure 3).