Antiarrhythmics are drugs used to treat cardiac arrhythmias. They are used primarily for tachycardia, an accelerated heartbeat. For bradycardia, a slowed heart response, a pacemaker is recommended rather than medication with antiarrhythmics.
What are antiarrhythmic drugs?
Antiarrhythmics are medications used to treat cardiac arrhythmias. These substances are largely manufactured synthetically and do not occur naturally. Antiarrhythmics (singular: antiarrhythmic) is the medical term for drugs used to treat cardiac arrhythmias. The classification of these pharmaceuticals is officially defined in a 4-class division. The criterion is the physiological mechanism of action. Some antiarrhythmics act at several points in the metabolism, which is why their classification in the system is difficult. Therefore, the classification is also under discussion, especially since unofficial presentations name a 5th class. This includes antiarrhythmics, which do not appear in the official version. In addition, the four classes contain only drugs against fast cardiac arrhythmias (tachycardias). Slow cardiac arrhythmias (bradycardias) can also be treated with some drugs, but these pharmaceuticals are not included in the standard definition. These agents play a minor role because slow arrhythmias are quite predominantly compensated with pacemakers rather than antiarrhythmic drugs.
Application, effect, and use
Class I antiarrhythmic drugs are the sodium channel blockers. They decrease the influx of sodium into the heart muscle cells. Sodium is crucial for the formation of action potentials (electrical excitation). There are 3 groups of sodium blockers, which differ in their fine effect on the action potential, but all have a direct dampening effect on the heart muscle cells. Class II antiarrhythmic drugs are the well-known beta receptor blockers, or beta blockers for short. These drugs affect the cardiac nerve complex. Here they block the beta-adrenoceptors, which are signaling sites on the nerve cells that are stimulated by the stress hormone adrenaline. The end result is that the heart reacts less to hormonal stimulation and works in a more balanced way. Class III are the potassium channel blockers. Potassium is also involved in the excitation of the heart muscle cell. The potassium channel blockers delay the outflow of the mineral from the cell, slowing down each heartbeat. This also results in a more regular heartbeat. Class IV of antiarrhythmic drugs includes calcium channel blockers. These pharmaceuticals reduce the uptake of calcium at the nerve cells of the coronary pacemaker. The lowered nervous output results in a lowered pulse. Finally, there are the unclassified antiarrhythmics, which include potassium and magnesium, for example. These minerals are necessary for the function of nerve and muscle cells and can positively support the treatment of cardiac arrhythmias in patients with corresponding deficiency symptoms. Cardiac glycosides also belong to this “fringe group” of antiarrhythmics. They cause stronger contractions of the heart muscle with a simultaneously lowered pulse. Atropine is one of the few drugs given for rapid cardiac arrhythmias. The active substance blocks certain receptors on nerve cells, as do other antiarrhythmic drugs.
Herbal, natural, and pharmaceutical antiarrhythmics.
Antiarrhythmic drugs are largely substances that are synthetically produced and do not occur naturally. Some also originate from the secondary metabolism of plants. Scientists discovered the sodium channel blocker ajmaline in the Indian snakeroot (Rauvolfia serpentina). Quinidine, a substance from the quina tree (Chinona pubescens), also belongs to Class I of antiarrhythmics. Digoxin, which belongs to the cardiac glycosides, is technologically extracted from a native plant: The well-known foxglove (Digitalis) is a very old remedy. Belladonna (Atropa belladonna) is a notorious fruit of Central Europe, whose alkaloid, atropine, is widely used in medicine, rarely as an antiarrhythmic. Besides these substances of organic-synthetic or biological nature, there are also inorganic preparations. Potassium and magnesium are mineral components of our daily diet and are used in high doses as antiarrhythmics.Homeopathic preparations for cardiac arrhythmias are not considered alternatives to “official” antiarrhythmic drugs by mainstream medicine.
Risks and side effects
Antiarrhythmic drugs have a wide range of side effects overall because they are a variety of individual substances. Beta-blockers tend to be the best tolerated. Gastrointestinal problems, visual disturbances, and skin rash are most common. Psychological complications such as disorientation and depression are also among the undesirable effects. Paradoxically, side effects that affect the cardiovascular system appear. A change in medication or dose reduction is then inevitable. By no means unproblematic here are the active ingredients of plant origin in antiarrhythmics.
