Calcium gluconate is the drug of choice for treatment of certain types of cardiac crises. It does not decrease heart excitability, but rather strengthens your heart muscle contractions. In a case where your heart is beating rapidly but inefficiently, this fast-acting cardiac stimulant can help re-establish a normal sinus rhythm.
Basics
Calcium is a mineral that helps regulate your blood pressure and it stimulates your heart muscle to contract. Your heart needs a very specific amount of calcium to function at optimal capacity. Low calcium levels in your bloodstream will cause weak contractions, while too much calcium can cause your heart muscle to tighten and become less flexible. Calcium supplements come in a variety of forms, of which calcium gluconate is the weakest. Doctors sometimes administer it intravenously during a cardiac crisis.
Hyperkalemia
Hyperkalemia is a condition in which you have excess potassium in your bloodstream. Because potassium affects both muscle movements and electrical impulses, an excess can cause an irregular heartbeat. In severe cases, your heartbeat may become increasingly slower and your heart may begin to fibrillate --- to twitch without pumping blood. In an emergency situation, doctors may use calcium to stimulate cardiac contractions and bring your heart muscle function back to normal. Calcium, however, may irritate or damage the veins around your heart. Doctors usually choose calcium gluconate because it is the most mild form of calcium and is less likely to cause vascular damage. In an acute situation, however, doctors may choose calcium chloride--a more potent form of calcium--despite potential damage to your veins.
Surgical Crisis
During or immediately following surgery, some patients develop a condition known as malignant hyperthermia. This condition, which often is hereditary, causes high fever, difficulty breathing and a rapid, irregular heartbeat. If you have muscular dystrophy, you are susceptible to a similar reaction if you are exposed to the drugs that tend to trigger malignant hyperthermia. In either case, your surgical team may use calcium gluconate or calcium carbonate to strengthen and stabilize your heartbeat.
Only a Temporary Solution
Calcium --- either in gluconate or carbonate form --- is ideal for s cardiac crisis because it acts quickly, usually within 1 to 3 minutes. The effect, however, typically lasts only 30 to 60 minutes. Doctors may use other drugs, such as insulin or sodium bicarbonate, which act more slowly as a follow up to the calcium treatment. If you have persistent hyperkalemia, your doctor may advise you to change your diet to reduce your potassium intake, or she may prescribe diuretics to help your body eliminate potassium and reduce your fluid retention.
References
- University of Chicago Heart Diseases in Children Information Center: Calcium Gluconate
- Malignant Hyperthemia Association of the United States: Management of MH-Susceptible Patients
- "Texas Hearst Institute"; Hyperkalemia Revisited; Walter A. Parham, MD, et al.; 2006
- Beijing Medical University: Treatment of Hyperkalemia; Burton D Rose, MD
- PubMed.gov; Hyperkalemia; Nov. 15, 2009
- MayoClinic.com; Dantrolene; May 1, 2010
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