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Prajmaline
Prajmaline (Neo-gilurythmal) is a class Ia antiarrhythmic agent which has been available since the 1970s. Class Ia drugs increase the time one action potential lasts in the heart. Prajmaline is a semi-synthetic propyl derivative of ajmaline, with a higher bioavailability than its predecessor. It acts to stop arrhythmias Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ... of the heart through a frequency-dependent block of cardiac sodium channels. Mechanism Prajmaline causes a resting block in the heart. A resting block is the depression of a person's Vmax after a resting period. This effect is seen more in the atrium than the ventricle. The effects of some Class I antiarrhythmics are only seen in a patient who has a normal heart rate (~1 Hz). This is due to the effect of a pheno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiarrhythmic Agent
Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a group of pharmaceuticals that are used to suppress abnormally fast rhythms ( tachycardias), such as atrial fibrillation, supraventricular tachycardia and ventricular tachycardia. Many attempts have been made to classify antiarrhythmic agents. Many of the antiarrhythmic agents have multiple modes of action, which makes any classification imprecise. Vaughan Williams classification The Vaughan Williams classification was introduced in 1970 by Miles Vaughan Williams.Vaughan Williams, EM (1970) "Classification of antiarrhythmic drugs". In ''Symposium on Cardiac Arrhythmias'' (Eds. Sandoe E; Flensted-Jensen E; Olsen KH). Astra, Elsinore. Denmark (1970) Vaughan Williams was a pharmacology tutor at Hertford College, Oxford. One of his students, Bramah N. Singh, contributed to the development of the classification system. The system is therefore sometimes known as the Singh-Vaughan Williams classification. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ajmaline
Ajmaline (also known by trade names Gilurytmal, Ritmos, and Aritmina) is an alkaloid that is classified as a 1-A antiarrhythmic agent. It is often used to induce arrhythmic contraction in patients suspected of having Brugada syndrome. Individuals suffering from Brugada syndrome will be more susceptible to the arrhythmogenic effects of the drug, and this can be observed on an electrocardiogram as an ST elevation. The compound was first isolated by Salimuzzaman Siddiqui in 1931 from the roots of '' Rauvolfia serpentina''. He named it ''ajmaline'', after Hakim Ajmal Khan, one of the most illustrious practitioners of Unani medicine in South Asia. Ajmaline can be found in most species of the genus '' Rauvolfia'' as well as ''Catharanthus roseus''. In addition to Southeast Asia, ''Rauvolfia'' species have also been found in tropical regions of India, Africa, South America, and some oceanic islands. Other indole alkaloids found in ''Rauvolfia'' include reserpine, ajmalicine, serpen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrhythmias
Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia, and a resting heart rate that is too slow – below 60 beats per minute – is called bradycardia. Some types of arrhythmias have no symptoms. Symptoms, when present, may include palpitations or feeling a pause between heartbeats. In more serious cases, there may be lightheadedness, passing out, shortness of breath or chest pain. While most cases of arrhythmia are not serious, some predispose a person to complications such as stroke or heart failure. Others may result in sudden death. Arrhythmias are often categorized into four groups: extra beats, supraventricular tachycardias, ventricular arrhythmias and bradyarrhythmias. Extra beats include premature atrial contractions, premature ventricular contract ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paroxysmal Tachycardia
Paroxysmal tachycardia is a form of tachycardia which begins and ends in an acute (or paroxysmal) manner. It is also known as "Bouveret-Hoffmann syndrome". Cause The cause of this condition is not accurately known, though it is probably of nervous origin and can be aggravated by physical wear and tear. The symptoms are sometimes very alarming but it is not considered in itself dangerous. It has an increased risk of developing in WPW syndrome and LGL syndrome. Diagnosis Classification It can be divided by the origin: * supraventricular tachycardia * ventricular tachycardia Ventricular tachycardia (V-tach or VT) is a fast heart rate arising from the lower chambers of the heart. Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple episodes over a short perio ... References Cardiac arrhythmia Symptoms and signs: Cardiac Syndromes affecting the heart {{circulatory-disease-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradycardia
Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. It is considered to be a normal heart rate during sleep, in young and healthy or elderly adults, and in athletes. In some people, bradycardia below 60 BPM may be associated with fatigue, weakness, dizziness, sweating, and fainting. The term "relative bradycardia" is used to refer to a heart rate slower than an individual's typical resting heart rate. Athletes may have athletic heart syndrome, which includes bradycardia as part of the cardiovascular adaptations to training and participation. The word "bradycardia" is from the Greek βραδύς ''bradys'' "slow", and καρδία ''kardia'' "heart". Classification Sinus Atrial bradycardias are divided into three types. The first, respiratory sinus arrhythmia, is usually found in young and healthy adults. Heart rate increases during inhalation and decreases during exhalation. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaloids
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar structure may also be termed alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and, more rarely, other elements such as chlorine, bromine, and phosphorus.Chemical Encyclopedia: alkaloids xumuk.ru Alkaloids are produced by a large variety of organisms including , , |
Sodium Channel Blockers
Sodium channel blockers are drugs which impair the conduction of sodium ions (Na+) through sodium channels. Extracellular The following naturally-produced substances block sodium channels by binding to and occluding the extracellular pore opening of the channel: * Alkaloids: ** Saxitoxin (STX) ** Neosaxitoxin (NSTX) ** Tetrodotoxin (TTX) Intracellular Drugs which block sodium channels by blocking from the intracellular side of the channel include: * Local anesthetics: ''lidocaine'' * Class I antiarrhythmic agents * Various anticonvulsants: ''phenytoin, oxcarbazepine (derivative of carbamazepine)'' Unknown mechanism * Calcium has been shown to block sodium channels which explains the effects of hypercalcemia and hypocalcemia. * Lamotrigine is known to block sodium channels but it is not known whether it is extracellular or intracellular. * Cannabidiol (CBD) has been shown to cause inhibitory effects on sodium currents. This voltage-dependent inhibition is non-selective in nature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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