The effect of hyperkalemia on the myocardium

Written by Wei Shi Liang
Intensive Care Unit
Updated on September 01, 2024
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The primary mechanism by which hyperkalemia causes arrhythmias is due to dysfunction of myocardial conduction, which is also related to various other factors such as other myocardial lesions, failure, and ionic states. The main impact on the myocardium is on its excitability; myocardial excitability can decrease or even disappear, and its conductivity is also affected, causing a reduction in conductivity. The effect on myocardial automaticity is a decrease in automaticity. Electrocardiographically, there are manifestations such as a low P wave, prolonged PR interval, and widened QRS complex without disappearance; these are some of the presentations of hyperkalemia.

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Written by Zhao Xin Lan
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Clinical manifestations of hyperkalemia

The clinical manifestations of hyperkalemia are not specific. Early symptoms often include numbness in the limbs, sensory abnormalities, extreme fatigue, and muscle pain. In severe cases, there can be difficulties in swallowing, speaking, and breathing, paralysis of the limbs, and tendon reflexes may disappear. The central nervous system may show signs of restlessness, fainting, and confusion. Some may experience a slow heart rate, ventricular fibrillation, and in the most severe cases, it can lead to cardiac arrest. Other symptoms may include nausea, vomiting, diarrhea, and other gastrointestinal symptoms.

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Written by Wei Shi Liang
Intensive Care Unit
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Why does hyperkalemia cause acidosis?

The concentration of potassium ions in serum is 3.5 to 5.5 millimoles per liter, and concentrations above 5.5 millimoles per liter are considered hyperkalemia. In the state of hyperkalemia, potassium ions in the extracellular fluid move into the intracellular fluid, while hydrogen ions in the intracellular fluid move to the extracellular fluid. At this time, through a compensatory mechanism, there is an increase in hydrogen ions in the extracellular fluid, significantly higher than normal levels, resulting in acidosis. Therefore, hyperkalemia often accompanies metabolic acidosis, which in turn affects the renal tubular epithelial cells, causing an abnormal alkaline urine. This is the main reason why hyperkalemia leads to acidosis.

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Written by Luo Han Ying
Endocrinology
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What should not be eaten with hyperkalemia?

Potassium is an important element in human blood. Typically, the electrolytes we measure in blood tests include sodium, potassium, chloride, and calcium. Both low and high levels of potassium can have adverse effects on the body, especially hyperkalemia, which can cause sudden cardiac arrest and is considered dangerous in clinical settings. Patients with normal kidney function are less likely to develop hyperkalemia, which is more commonly seen in those who may have consumed Chinese herbal medicines containing high amounts of potassium for a long time. In patients with renal insufficiency, due to impaired kidney excretory function, hyperkalemia occurs more easily. Patients with hyperkalemia should generally avoid ACE inhibitors and ARB medications. For example, drugs like ACE inhibitors and spironolactone can further exacerbate hyperkalemia, so these types of medications are definitely not advisable. (The use of medications should be under the guidance of a professional doctor.)

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Written by Wei Shi Liang
Intensive Care Unit
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What are the symptoms of hyperkalemia?

Mild hyperkalemia can affect muscle tissues, causing mild muscle tremors, while severe hyperkalemia may reduce the excitability of neuromuscular functions, leading to weakness and even flaccid paralysis in the limbs. Hyperkalemia can also impact the heart, mainly resulting in decreased myocardial excitability, decreased myocardial conductivity, and decreased myocardial automaticity. The effects on the electrocardiogram (ECG) primarily manifest as low and widened P waves, widened QS complexes, decreased R waves, and elevated T waves. Regarding myocardial contractility, hyperkalemia mainly causes a decrease in contractility and can lead to metabolic acidosis.

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Written by Chen Li Ping
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Can hyperkalemia be cured?

The main focus is on the cause of hyperkalemia. If hyperkalemia is due to consuming foods rich in potassium, administration of potassium-containing solutions, transfusion of stored blood, use of potassium-sparing diuretics like spironolactone, or prolonged venipuncture causing severe shaking of the blood sample during transport, addressing these causes can prevent the occurrence of hyperkalemia. If hyperkalemia is caused by certain diseases, such as renal failure or adrenal insufficiency, active treatment of the underlying disease is required. If the renal failure is acute, recovery of kidney function might prevent the recurrence of hyperkalemia. However, if there is chronic renal insufficiency, there tends to be a higher recurrence rate of hyperkalemia. Therefore, whether hyperkalemia can be cured largely depends on identifying the underlying cause.