Hyperkalemic Atrial Standstill in Neonatal Calf Diarrhea

Abstract

Hyperkalemia has been associated with cardiac abnormalities and muscular disorders. Hyperkalemia is a common problem associated with the acid-base and electrolyte disturbances that occur in neonatal calves having acute diarrhea. Occasional calves with acute neonatal diarrhea, metabolic acidosis, and hyperkalemia have cardiac rate or rhythm abnormalities. Bradycardia observed in three such calves was found to represent atrial standstill and was attributed to hyperkalemia. (Journal of Veterinary Internal Medicine 1992; 6:294-297)INFECTIOUS DIARRHEA is a frequent and often fatal disease affecting calves in the first weeks of Numerous causative organisms have been r e p~r t e d ,~ including enterotoxigenic Escherichia coli, rotavirus, coronavirus, Salmonella spp, Clostridia spp, and crypto~poridia.~-~ The profuse diarrhea associated with infection by these organisms can lead to significant losses in bicarbonate, electrolytes, and water and severe lifethreatening metabolic disturbances. lo Concomitant metabolic acidosis can cause significant transcellular electrolyte shifts whereby potassium ions leave the cell to enter the extracellular fluid in exchange for hydrogen ions."-14 Dehydration can further contribute to this hyperkalemic state by decreasing renal blood flow, thereby decreasing potassiumIn response to hypovolemia, sodium reabsorption in the proximal tubule results in decreased delivery of sodium and water to the distal tubular sodium-dependent potassium secretory site, which results in potassium accumulation.I6 As the serum potassium increases (>5.5 mEq/ L), aberrations in cardiac excitability occur and are manifested as progressive atrial standstill and, if left untreated, ultimately as ventricular fibrillation or asysIn this article, we describe three calves in which diarrhea was believed to contribute to hyperkalemia along with the associated electrocardiographic finding of atrial standstill. cine as a representative of a recent farm outbreak of neonatal calf diarrhea during which seven calves had died. The calf had received colostrum, an E. coli bacterin, and a selenium injection at birth. Before amval, this calf had been treated with scour boluses, oral electrolytes, and penicillin. Calf 1At initial examination, the calf was recumbent, dehydrated (-8%), hypothermic (T = 97.OoF/36. 1 1 "C), and had profuse watery diarrhea of 12 hours duration. Auscultation revealed bradycardia (heart rate = 88 beats/ min), poor pulse quality, and occasional pulse deficits. Electrocardiographic analysis showed an irregular rhythm, no P-waves, and inconsistent supraventricular premature complexes with aberrant ventricular conduction ( Figure 1A). A serum biochemical profile indicated marked hyperkalemia (K = 9.6 mEq/L), azotemia (BUN = 105.0 mg/dL), increased creatinine concentration (6.1 mg/dL), and an increased anion gap (34.0 mEq/L).An intravenous catheter was placed in the jugular vein and therapy with 5% dextrose and 150 mEq NaHC03/L was instituted. Electrocardiographic tracings were done every 15 minutes until a ...

Electrocardiographic findings in 130 hospitalized neonatal calves with diarrhea and associated potassium balance disorders

“…Our study confirms that hyperkalemia is a clinically relevant electrolyte imbalance in neonatal diarrheic calves that is associated with typical ECG manifestations such as increased QRS duration, tall and peak‐shaped appearing T waves, and findings of atrial standstill and life‐threatening arrhythmias, that have also been previously described in single reports of affected neonatal diarrheic calves or experimental investigations . However, to the author's knowledge, this is the first study to statistically determine the sequence of ECG changes as plasma c K + increases in domestic animals or humans with naturally acquired hyperkalemia.…”

“…Electrocardiographic (ECG) manifestations in hyperkalemic human patients typically include tall and symmetric T waves, widening of the QRS complex, progressive flattening and eventually disappearance of P waves, and life threatening dysrhythmias or ventricular escape rhythms . Similar findings occur in calves with experimentally induced hyperkalemia, and experimentally induced or naturally acquired diarrhea . However, knowledge on ECG findings in calves with naturally acquired diarrhea is based on case reports, case series, or small study populations of calves with marked increases in c K + .…”

Effect of Intravenous Small‐Volume Hypertonic Sodium Bicarbonate, Sodium Chloride, and Glucose Solutions in Decreasing Plasma Potassium Concentration in Hyperkalemic Neonatal Calves with Diarrhea

“…Rapid correction of hyperkalemia is considered decisive in the treatment of affected calves and associated clinical alterations, which are characterized by cardiac conduction abnormalities and arrhythmias, marked dehydration, and skeletal muscle weakness in spite of normal or only slightly elevated D‐lactate concentrations,8, 13 as also observed in calves of the present study. An immediate and sustained potassium‐lowering effect of hypertonic (8.4%) sodium bicarbonate infusion solution has already been demonstrated in previous studies,17, 18, 38 with the observed initial decrements of c K being most closely associated with increases in venous blood pH 17.…”

“…Due to the potential cardiotoxicity, acute hyperkalemia represents a potentially life‐threatening state and has historically been considered to be an important cause of death in neonatal calves with diarrhea 12. Electrocardiographic manifestations of hyperkalemia typically include flattened or missing P‐waves, increased QRS duration, large and spiked T‐waves, and R‐R irregularities 9, 13, 14, 15. Additionally, the clinical picture of hyperkalemic diarrheic calves is characterized by severe clinical dehydration, cyanosis, and impaired ability to stand8 and affected calves are frequently presented with signs of shock.…”

Terminal atrial standstill with ventricular escape rhythm in a neonatal calf with acute diarrhea

“…Electrocardiography can be further used to assess the effectiveness of therapy (5). Atrial standstill and other arrhythmias have been documented in diarrheic calves having metabolic acidosis and hyperkalemia (4,6).…”