Hyperkalemia secondary to renal hypoperfusion in a dog with third-degree atrioventricular block

To demonstrate a critical role of artificial cardiac pacing to normalize severe bradyarrhythmia-induced hyperkalemia in a dog with third-degree atrioventricular (AV) block.

A dog was presented for evaluation of severe hyperkalemia and bradyarrhythmia. ECG revealed third-degree AV block with heart rate of 10-20 min, which was lower than usual ventricular escape rate. The etiology of severe hyperkalemia was considered secondary to significantly decreased renal perfusion and potassium excretion as a result of poor cardiac output caused by the AV block. Since potassium disorders may lead to life-threatening conditions such as cardiopulmonary arrest, artificial cardiac pacing was immediately pursued. Within 1 hour, serum potassium concentration was normalized, which confirmed that severe hyperkalemia occurred primarily due to third-degree AV block. The dog was then treated with permanent pacemaker implantation. A recheck evaluation 3-month post pacemaker implantation showed normal serum potassium concentration and the dog was clinically healthy.

This report describes hyperkalemia secondary to significantly decreased cardiac output and renal hypoperfusion caused by third-degree AV block. The authors propose that artificial cardiac pacing must be considered as an emergency treatment for bradyarrhythmia-induced hyperkalemia, which ultimately restores cardiac output and renal perfusion and normalizes serum potassium concentration.