High potassium levels can lead to a type of heart attack called sudden cardiac arrest. Unlike regular heart attacks, sudden cardiac arrest is characterized by a sudden and unexpected cessation of your heartbeat. A sudden cardiac arrest usually occurs as a result of a heart arrhythmia, or abnormal heart rhythm, which can be caused by high potassium levels in the blood.
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Electrical System of the Heart
The rate and rhythm of your heartbeat is controlled by an electrical system within your heart. The heart contains a structure called the sinoatrial, or SA, node. This structure is often referred to as the heart’s pacemaker because it sends out the initial electrical signal that controls the heartbeat. The electrical signal from the SA node travels into the right atrium, where it signals the atria to contract. The electrical signal then travels to the atrioventricular, or AV, node, where it signals the ventricles to contract. When electrical signals follow this pattern, the heartbeat remains normal.
Hyperkalemia and Arrhythmia
Potassium is a mineral as well as an electrolyte, which means it has an electrical charge. If you have too much potassium in your blood, the electrical signal it carries can lead to changes in your heartbeat called arrhythmias. If arrhythmias become severe, they can change the heart’s pumping action to such an extent that normal blood flow is interrupted, which can lead to sudden cardiac arrest.
Unlike most heart attacks, sudden cardiac arrest occurs suddenly and does not have many warning signs. The first sign of a sudden cardiac arrest is usually loss of consciousness with the absence of a pulse. Some people may feel dizzy or lightheaded or experience chest pain, shortness of breath, nausea or vomiting.
Sudden cardiac arrest requires immediate emergency treatment using a defibrillator. A defibrillator sends an electric shock to the heart in an attempt to restore normal heart rhythm. According to the National Heart, Lung and Blood Institute, 95 percent of people who experience a sudden cardiac arrest die within minutes.
If you survive a sudden cardiac arrest, you will be sent to the hospital for further treatment. To restore your potassium levels to normal, you may receive intravenous administration of glucose and insulin, which help the cells absorb excess amounts of potassium, according to the Milton S. Hershey Center. If your high potassium levels were caused by failing kidneys, dialysis may be given to help you flush out excess potassium.
According to the National Heart, Lung and Blood Institute, once you have had a sudden cardiac arrest you are at risk of a recurrence. To reduce your risk, it is important to closely monitor your potassium levels. If you have disease that affects your body’s regulation of potassium, avoid high potassium foods, such as bananas, tomatoes, oranges, spinach, potatoes, peas and beans.