Can Magnesium Cause Cardiac Arrest?
Yes, a severe magnesium overdose can lead to cardiac arrest. However, this can affect only a specific group of people with kidney insufficiency, Addison’s disease, hypothyroidism, or lithium therapy. In any case, the kidneys will effectively dispose of any overload of magnesium [1].
Magnesium plays a crucial role in maintaining regular cardiac conduction, rhythm, and vascular tone. Hypomagnesemia, or low magnesium levels, can cause myocardial excitability resulting in arrhythmias such as ventricular tachycardia and torsades de pointes, which can potentially lead to cardiac arrest [14]. However, it's important to note that magnesium itself does not cause cardiac arrest. In fact, studies have shown that magnesium treatment can suppress ventricular arrhythmias in acute myocardial infarction [15]. However, excessively high levels of magnesium (hypermagnesemia) can also be harmful and lead to serious health issues, including cardiac arrest, but this condition is rare and usually occurs only if magnesium is overused or misused, especially in people with kidney problems.
What is magnesium, and what is it used for as a supplement?
Magnesium is a vital mineral in the human body. It is the fourth most abundant mineral and is key for more than 300 biochemical reactions in the body. With this wide range of reactions, it is crucial for the proper functioning of the cardiovascular, alimentary, endocrine, and osteoarticular systems [2, 3].
Nowadays, magnesium supplements are used in the treatment of various conditions [4]. For instance, magnesium is used to help treat nocturnal leg cramps, pre-eclampsia, diabetes, depression, Parkinson's, and Alzheimer's disease. However, it found its use also in the cardiovascular spectrum of diseases, such as hypertension and some types of arrhythmias. Supportive use can also be prescribed for conditions like asthma, migraine headaches, epilepsy, cerebral hemorrhage, and stroke [4].
Mg is critical for energy metabolism and normal muscle function. The need for magnesium increases with the amount of physical activity. There are also indications that this mineral can increase glucose availability in various organs. By doing so, it can increase brain and muscle performance. In the muscles, a higher glucose availability delays lactate accumulation and, therefore, muscle soreness [5].
Magnesium is also an important modulator in the biochemistry of the brain. It influences the neurotransmission pathways, which are linked with depression. Supplementation with magnesium was found to increase the effectiveness of antidepressant medications [2].
More than half of the magnesium in the body is found in the bones. It is not only stored in the hard scaffolding of the human body, it also plays an important role in skeleton function. An adequate level of magnesium benefits bone structure and density, making it stronger [6].
How much magnesium should I take daily?
The daily recommended intake of magnesium varies depending on age and gender. For adults aged 19-30 years, the recommendation is 400 mg for men and 310 mg for women. For adults aged 31 and above, the recommendation is 420 mg for men and 320 mg for women [14], [15], [16]. However, it's important to note that excessive intake of magnesium can pose a health threat [17]. For individuals with abnormal kidney function, the magnesium dose should be reduced by 50% and closely monitored [18]. Always consult with a healthcare provider before starting any new supplement regimen.
How does magnesium impact the heart?
Magnesium plays a key role in the heart’s energy production and use. It allows the heart to maintain its structural and functional integrity [7].
The Mg ions influence the cells of the heart (cardiomyocytes) directly. It helps with the calcium regulation inside them. Also, it protects the cardiac muscle from ATP depletion. ATP is the direct source of energy for the heart [8].
Not only does magnesium support the function of the heart on a metabolic level, but it is also important for the electric activity of the heart. It influences the generation and propagation of the action potentials, the electrical impulses spreading through the heart and activating the contraction. It causes hemodynamic changes through the suppression of vasospasm and the lowering of vascular resistance [7]. By this mechanism, it can enhance the blood perfusion of the heart and stabilize the blood supply to pathologically affected areas.
Magnesium lowers the early mortality incidence in some cardiovascular conditions. It was found to reduce the size of a myocardial infarction, increasing the healthy cardiac muscle left. Also, in arrhythmia, magnesium was found to be beneficial. It decreases the occurrence of serious ventricular arrhythmias [7].
Magnesium was also found to have an anti-infarct effect. Linked to the ATP-sensitive potassium channels in the heart and heart vessels, which are opening during the metabolic stress of the infarction, it is improving cardiac function [9].
In addition, magnesium has been found to increase cardiac output and heart rate while decreasing mean arterial blood pressure and systemic vascular resistance [10]. With this, magnesium increases heart performance.
What is cardiac arrest, and what can cause cardiac arrest?
Cardiac arrest (CA) is a condition where the heart suddenly stops beating. A condition like this can arise due to a problem with the electric conduction system of the heart. Problems with the conduction system exhibit irregular electric activity, also known as arrhythmia. In some cases, the heart may stop pumping blood to the body entirely. This is then referred to as CA and can be fatal if not treated immediately [11, 12].
CA can be caused by several factors. One of the most common is ventricular fibrillation. In this condition, the lower chamber of the heart is malfunctioning. Its malfunction is electrical and occurs when there are many small circles of electric activity in the ventricle simultaneously. This desynchronized activity leads to the cessation of the ventricle's primary pumping function. In the end, the heart does not supply the brain or itself with blood. Ventricular fibrillation leads to cessation of heart action and, if not defibrillated, death (sudden cardiac death) [11].
Another common cause of cardiac arrest is atrial fibrillation. During this fibrillation, the main heart pacemaker, the sinoatrial (SA) node, located in the right atrium, is not able to send out the correct electrical impulses. This can induce ventricular fibrillation and cause ineffective blood pumping, leading to cardiac arrest [11].
Other conditions that can lead to cardiac arrest include coronary artery disease. Here, a plaque created during atherosclerosis leads to a heart attack. The biochemical imbalance and the damage to the heart can lead to functional problems like arrhythmia [13]. Some structural pathologies, like cardiomyopathies, can lead to cardiac arrest too, and congenital defects of the heart can eventually lead to heart arrest.
A cardiac arrest can also be caused by a severe lack of oxygen, large-volume blood loss, or extreme physical activity. Ion imbalance can potentially also lead to electrical problems in the heart and, consequently, heart arrest. Among the dangers are the deficits of potassium or magnesium in the blood [13].
Risk factors for cardiac arrest include smoking, hypertension, obesity, an inactive lifestyle, and a previous heart attack. Also, the age over 45 for men or over 55 for women is a risk factor [11].
What to do in cardiac arrest?
In the event of a cardiac arrest, the following steps should be taken:
- Identify the cardiac arrest: Ensure the patient is unresponsive, without central pulses, and not breathing normally [14], [15], [16].
- Call for help: Activate the emergency response system immediately [14], [15], [16].
- Start CPR: Begin chest compressions at a rate of 100 to 120 compressions per minute. If trained and confident, start with 30 chest compressions before giving two rescue breaths [17], [18].
- Use an AED if available: Public access defibrillation has added another layer of response. If available, it should be activated and utilized [14], [15], [16].
- Continue CPR until help arrives: CPR should be continued until the arrival of emergency responders [14], [15].
Remember, immediate action is crucial as irreversible cerebral damage can occur within 90-300 seconds of cardiac arrest [19].