Cardiac arrhythmias include any interruption in the normal rate or rhythm of the heartbeat. Arrhythmias occur as a result of variations in the mechanical function, electrical conduction or electrolyte imbalances in the heart. Electrolytes, which are minerals carrying an electrical charge, are maintained within very tight parameters in the bloodstream, tissues and cells. Alterations in electrolytes, measured by a comprehensive metabolic profile blood test, or CMP, can cause arrhythmias that require medical treatment before life-threatening effects occur.
Potassium and Sodium
Potassium, the dominant electrolyte inside cells, has the most definitive effect on cardiac rhythms. Sodium, the dominant electrolyte outside cells, balances cellular potassium with fewer direct cardiac effects but more neurological effects in either excessive or deficient conditions. Potassium primarily affects the lower heart chambers, the ventricles, and serious problems related to imbalance include premature ventricular contractions, ventricular tachycardia, ventricular fibrillation and even sudden cardiac death. Both low potassium, hypokalemia, and high potassium, hyperkalemia, together with some medications, such as caffeine and alcohol, can precipitate serious arrhythmias.
Calcium
Calcium, which is found in bones, cells and blood, is necessary for muscle contractions and nerve conduction and is part of treatments for hyperkalemia, hypermagnesemia, hyperphosphatemia and hypocalcemia. Your body controls the amount of calcium available from dietary consumption, digestion, absorption, excretion and hormonal regulation. Calcium channels, a type of molecular pump located in cell membranes, adjust muscle excitation, contraction and calcium flow in the heart. Excess calcium, hypercalcemia, and low calcium, hypocalcemia, affects the ventricles, thereby causing arrhythmias similar to potassium.
Phosphorus
Phosphorus excess, which is known as hyperphosphatemia, occurs most often with chronic kidney disease and exhibits symptoms of the basic disorder, hypocalcemia. If you've had a heart attack, even small changes in phosphorus can increase the risk of a serious ventricular cardiac arrhythmia. Dialysis and phosphate binders are used to treat hyperphosphatemia. Low phosphate, hypophosphatemia, can result from thyroid disorders, hypercalcemia and hypomagnesemia. Oral replacement is preferred, since intravenous treatment can precipitate a rapid calcium deficit.
Magnesium
Magnesium loss, hypomagnesemia, causes neurologic symptoms and cardiac arrhythmias with symptoms similar to hypokalemia and hypocalcemia, which frequently co-exist. Low potassium and calcium can't be alleviated until magnesium is replaced. Cardiac arrhythmias include tachycardias, fast heart rate, and ventricular arrhythmias. Magnesium loss not reflected in blood testing, but is suspected, requires urine testing for diagnosis. Chronic kidney disease causing hypermagnesemia leads to respiratory paralysis and cardiac arrhythmias with intravenous calcium the mode of therapy.
Electrocardiogram
The electrocardiogram, which is a diagnostic, graphic display of electrical conduction through the heart chambers, reflects specific electrolyte imbalances, excess medication effects, as well as mechanical malfunction. Atrial, or upper chamber, malfunctions are frequently mechanical. Such malfunctions include heart disease, chronic respiratory disease, medications, thyroid disorders and the aging process but they can also be associated with electrolyte imbalances. If treated before becoming chronic, some atrial arrhythmias can respond to treatment of the underlying cause.
