Hyperkalaemia induced complete atrioventricular block with a narrow QRS complex

Abstract

A 77 year old woman was admitted to the hospital because of dyspnoea and dizziness for 3 hours. Upon physical examination, her blood pressure was 80/40 mm Hg, with a regular pulse rate of 33 beats per minute. The ECG on admission exhibited P waves with a rate of 100 beats/min and a positive pattern in leads II, III and aVF, third degree atrioventricular (AV) block, AV dissociation with a ventricular rate of 33 beats/min, an 80-ms wide QRS complex, and QT interval of 640 ms (panel A). Temporary percutaneous pacing was begun immediately, resulting in a prompt improvement in the stabilisation of the haemodynamic status. The laboratory findings included a serum potassium level of 7.99 mEq/l, sodium 137.1 mEq/l, urea nitrogen 46.62 mg/dl, and creatinine 3.22 mg/dl. The arterial blood gas analysis revealed a pH of 7.41, pO 2 74.0 mm Hg, and pCO 2 31.8 mm Hg. Her blood potassium level decreased rapidly, and after 2 hours of being treated with a glucose solution, insulin and bicarbonate, it became 5.03 mEq/l. At that time her ECG exhibited normal sinus rhythm (panel B).Hyperkalaemia induced complete AV block without prolongation of the QRS complex is a rare condition. Hyperkalaemia can be responsible for a wide spectrum of electrocardiographic abnormalities. In general, hyperkalaemia produces a gradual depression of the excitability, conduction velocity of the specialised pacemaker cells and conducting tissues throughout the heart. High serum potassium levels are thought to impair the conduction in the Purkinje fibers and ventricles more than in the AV node, although complete atrioventricular block can occur. In this case temporary pacing and excretion of the excessive levels of the serum potassium were essential.

Advanced Atrio-Ventricular Blocks in a Foal Undergoing Surgical Bladder Repair: First Step to Cardiac Arrest?

“…An additional increase in parasympathetic tone can further reduce conduction of the AV node and might induce complete AV blocks ( 14 ). Purkinje fibers seem to be even more sensitive to hyperkalemia than AV or sinus node, therefore precipitating the occurrence of AV blocks ( 15 ). Hyperkalemia should be treated promptly whenever diagnosed and fluid therapy should be initiated.…”

Diltiazem-induced Transient Complete Atrioventricular Block in an Elderly Patient with Acute on Chronic Renal Failure

“…Although effects of elevated potassium are more pronounced in Purkinje fibers and ventricular myocites, impairment of AV nodal cells can occur as well. Hyperkalemia as the sole cause of high grade AV block is usually severe [8], however, it might have played a minor adjuvant role for this patient. …”

Marked Symptomatic Bradycardia Associated with Profound Hyperkalemia

“…Mirandi reported data on a hypertensive patient with severe hyperkalemia secondary to postobstructive uropathy with AV block who was receiving multiple AV nodal blocking agents [10]. Rapid or significant changes in the serum potassium concentration can have life-threatening consequences, but several cases of hyperkalemiainduced complete AV block with a narrow QRS complex have been reported in the literature [10][11][12]. Mattu reported 5 cases that showed the classic ECG manifestations of hyperkalemia.…”