Cardiac Arrhythmia Management

Treatment

The American Heart Association recommends rapid IV infusion of magnesium sulfate (25-50 mg/kg; maximum 2g) for torsades de pointes ventricular tachycardia regardless of cause 1
Intravenous magnesium sulfate is effective in patients with severe asthma exacerbations, reducing hospitalization rates and improving lung function, as recommended by the American Academy of Allergy, Asthma, and Immunology 2
IV magnesium sulfate is preferred over aminophylline for severe asthma and COPD exacerbations due to its better safety profile and comparable efficacy, as recommended by the American College of Allergy, Asthma, and Immunology and the GOLD guidelines 3, 4
The administration of IV magnesium sulfate has been shown to improve peak expiratory flow from 225 to 297 L/min compared to 208 to 216 L/min in the placebo group, as demonstrated in a randomized, double-blind, placebo-controlled study 5

Baseline vital signs, deep tendon reflexes, respiratory rate and depth, and serum magnesium and renal function tests should be obtained before administering magnesium sulfate, as recommended by the American Heart Association 6
Patients receiving magnesium sulfate should be monitored for signs of magnesium toxicity, including flushing, sweating, hypotension, respiratory depression, and loss of deep tendon reflexes, as warned by the American Heart Association 6
Monitoring of vital signs, including blood pressure, heart rate, and oxygen saturation, is recommended during the administration of intravenous magnesium sulfate, as suggested by the American Heart Association and American Thoracic Society 6, 4, 3, 7, 8, 9, 2, 10

The recommended dosage of magnesium sulfate varies by condition:

Condition	Dose
Severe hypertension	14g loading dose (4g IV + 5g IM in each buttock), followed by 5g IM every 4 hours
Severe asthma exacerbation	2g IV over 20 minutes
COPD exacerbation	1.2-2g over 20 minutes
Pediatric patients	25-50 mg/kg (maximum 2 g) administered over 10-20 minutes

Calcium salts should be available to counteract potential magnesium toxicity, as recommended by the American Heart Association 6
In patients with renal insufficiency, the maximum dosage should not exceed 20 g/48 hours with frequent serum magnesium monitoring, as recommended by the American Heart Association and American College of Chest Physicians 8, 4, 2
Magnesium sulfate should be used with caution in patients with digitalis, as it may cause serious changes in cardiac conduction, as warned by the European Society of Cardiology 15
Excessive neuromuscular blockade may occur in patients receiving parenteral magnesium sulfate and a neuromuscular blocking agent, as warned by the American Heart Association 6