Complete Heart Block due to Hyperkalemia in Chronic Kidney Disease: A Case Report

INTRODUCTION

Potassium has an important role in the electrophysiological function of the myocardium. Na–K ATPase pumps maintain a resting membrane potential of −90 mV across the myocardial cell membrane.¹ Hyperkalemia is a common electrolyte abnormality seen in chronic kidney disease patients.² Hyperkalemia is associated with electrocardiographic abnormalities as it decreases the excitability and conduction velocity of pacemaker cells and conducting tissues. Typical electrocardiogram (ECG) findings in hyperkalemia are tall T waves and a short QT interval, which progresses to prolonged PR interval and the latter loss of P waves and widening of the QRS complex. Classical of the “sine wave” pattern,³ complete atrioventricular (heart block) block is a very rare presentation of hyperkalemia.⁴

CASE PRESENTATION

A 65-year-old male was admitted to the hospital with complaints of giddiness that was associated with syncope for the last 2–3 days. He had hypotension with a blood pressure of 80/50 mm Hg and bradycardia of 30 beats per minute. He had a known case of chronic kidney disease for the last 5 years but not on any medical management. His ECG was done, which was suggestive of complete heart block (complete A–V dissociation) (Fig. 1). An emergency temporary pacemaker was inserted and he was stabilized. On evaluation, we found that his serum potassium level was very high (Table 1), and kidney function was also abnormal, but he had normal cardiac biomarkers. We have started all standard antihyperkalemic measures like intravenous calcium gluconate, soda bicarbonate, glucose and insulin drip, and oral potassium binder. He responded very well to the treatment, and his ECG was reverted to normal sinus rhythm (Fig. 2). He was discharged on the 3rd day of hospitalization, after removing his pacemaker. On falling up, he was absolutely normal.

DISCUSSION

Potassium has an important role in the electrophysiological function of the myocardium. Na–K ATPase pumps maintain a resting membrane potential of −90 mV across the myocardial cell membrane.¹ Hyperkalemia is a common electrolyte abnormality seen in chronic kidney disease patients.² Hyperkalemia is associated with electrocardiographic abnormalities as it decreases the excitability and conduction velocity of pacemaker cells and conducting tissues. Typical ECG findings in hyperkalemia are tall T waves and a short QT interval, which progresses to prolonged PR interval and the latter loss of P waves and widening of the QRS complex. Classical of the “sine wave” pattern.³ Complete atrioventricular (heart block) block is a very rare presentation of hyperkalemia.⁴

Electrocardiogram is not a reliable indicator of mild-to-moderate hyperkalemia, but a very high increase in serum potassium concentrations produces classical ECG manifestations. Complete heart block occurs when the electrical conduction from the supraventricular tissues to ventricles is lost. Hyperkalemia can be associated with ECG abnormality. Complete heart blocks are seen in patients with preexisting cardiac diseases. Complete atrioventricular (heart block) block is a very rare presentation of hyperkalemia. Our case is a classical example of complete heart block secondary to hyperkalemia in a preexisting chronic kidney disease patient.

CONCLUSION

Complete atrioventricular dissociation (heart block) is a very rare presentation of hyperkalemia. Hyperkalemia can be associated with ECG abnormality, but complete heart blocks are usually seen in patients with preexisting cardiac diseases. Our case is a classical example of complete heart block secondary to hyperkalemia in a preexisting chronic kidney disease patient. Every physician should be aware that a CKD patient can be present with complete atrioventricular dissociation without preexisting heart disease.

ORCID

Ankush Balasaheb Kolhe https://orcid.org/0000-0002-8698-2548

REFERENCES

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