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Cardiac Arrhythmia Suppression Trial
The Cardiac Arrhythmia Suppression Trial (CAST) was a double-blind, randomized, controlled study designed to test the hypothesis that suppression of premature ventricular contraction, premature ventricular complexes (PVC) with class I antiarrhythmic agents after a myocardial infarction (MI) would reduce Mortality rate, mortality. It was conducted between 1986 and 1989 and included over 1700 patients in 27 centres. The study found that the tested drugs increased mortality instead of lowering it as was expected. The publication of these results in 1991/92, in combination with large follow-up studies for drugs that had not been tested in CAST, led to a paradigm shift in the treatment of MI patients. Class I and III antiarrhythmics are now only used with extreme caution after MI, or they are contraindicated completely. Background Study design The second Cardiac Arrhythmia Suppression Trial (CAST II) modified the enrollment criteria to include patients at higher risk for serious ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premature Ventricular Contraction
A premature ventricular contraction (PVC) is a common event where the heartbeat is initiated by Purkinje fibers in the ventricles rather than by the sinoatrial node. PVCs may cause no symptoms or may be perceived as a "skipped beat" or felt as palpitations in the chest. PVCs do not usually pose any danger. The electrical events of the heart detected by the electrocardiogram (ECG) allow a PVC to be easily distinguished from a normal heart beat. However, very frequent PVCs can be symptomatic of an underlying heart condition (such as arrhythmogenic right ventricular cardiomyopathy). Furthermore, very frequent (over 20% of all heartbeats) PVCs are considered a risk factor for arrhythmia-induced cardiomyopathy, in which the heart muscle becomes less effective and symptoms of heart failure may develop. Ultrasound of the heart is therefore recommended in people with frequent PVCs. If PVCs are frequent or troublesome, medication (beta blockers or certain calcium channel blockers) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiarrhythmic Agent
Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a class of drugs 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. Action potential The cardiac myocyte has two general types of action potentials: conduction system and working myocardium. The action potential is divided into 5 phases and shown in the diagram. The sharp rise in voltage ("0") corresponds to the influx of sodium ions, whereas the two decays ("1" and "3", respectively) correspond to the sodium-channel inactivation and the repolarizing efflux of potassium ions. The characteristic plateau ("2") results from the opening of voltage-sensitive calcium channels. Each phase utilizes different channels and it is useful to compar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myocardial Infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom is retrosternal Angina, chest pain or discomfort that classically radiates to the left shoulder, arm, or jaw. The pain may occasionally feel like heartburn. This is the dangerous type of acute coronary syndrome. Other symptoms may include shortness of breath, nausea, presyncope, feeling faint, a diaphoresis, cold sweat, Fatigue, feeling tired, and decreased level of consciousness. About 30% of people have atypical symptoms. Women more often present without chest pain and instead have neck pain, arm pain or feel tired. Among those over 75 years old, about 5% have had an MI with little or no history of symptoms. An MI may cause heart failure, an Cardiac arrhythmia, irregular heartbeat, cardiogenic shock or cardiac arrest. Most MIs occur d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mortality Rate
Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular Statistical population, population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of deaths per 1,000 individuals per year; thus, a mortality rate of 9.5 (out of 1,000) in a population of 1,000 would mean 9.5 deaths per year in that entire population, or 0.95% out of the total. It is distinct from "morbidity", which is either the prevalence or Incidence (epidemiology), incidence of a disease, and also from the incidence rate (the number of newly appearing cases of the disease per unit of time). An important specific mortality rate measure is the crude death rate, which looks at mortality from all causes in a given time interval for a given population. , for instance, the Central Intelligence Agency, CIA estimates that the crude death rate globally will be 7.7 deaths per 1,000 people in a population p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paradigm Shift
A paradigm shift is a fundamental change in the basic concepts and experimental practices of a scientific discipline. It is a concept in the philosophy of science that was introduced and brought into the common lexicon by the American physicist and philosopher Thomas Kuhn. Even though Kuhn restricted the use of the term to the natural sciences, the concept of a paradigm shift has also been used in numerous non-scientific contexts to describe a profound change in a fundamental model or perception of events. Kuhn presented his notion of a paradigm shift in his influential book ''The Structure of Scientific Revolutions'' (1962). Kuhn contrasts paradigm shifts, which characterize a Scientific Revolution, to the activity of normal science, which he describes as scientific work done within a prevailing framework or paradigm. Paradigm shifts arise when the dominant paradigm under which normal science operates is rendered incompatible with new phenomena, facilitating the adoption of a ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Left Ventricular Ejection Fraction
An ejection fraction (EF) is the volumetric fraction (mathematics), fraction (or portion of the total) of fluid (usually blood) ejected from a chamber (usually the heart) with each contraction (or cardiac cycle, heartbeat). It can refer to the cardiac Atrium (heart), atrium, cardiac ventricle (heart), ventricle, gall bladder, or leg veins, although if unspecified it usually refers to the left ventricle of the heart. EF is widely used as a measure of the pumping efficiency of the heart and is used to classify heart failure types. It is also used as an indicator of the severity of heart failure, although it has recognized limitations. The EF of the left heart, known as the left ventricular ejection fraction (LVEF), is calculated by dividing the volume of blood pumped from the Ventricle (heart), left ventricle per beat (stroke volume) by the volume of blood present in the left ventricle at the end of diastolic filling (end-diastolic volume). LVEF is an indicator of the effectiveness of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encainide
Encainide (trade name Enkaid) is a class Ic antiarrhythmic agent. It is no longer used because of its frequent proarrhythmic side effects. Synthesis See also * Iferanserin * Cardiac Arrhythmia Suppression Trial The Cardiac Arrhythmia Suppression Trial (CAST) was a double-blind, randomized, controlled study designed to test the hypothesis that suppression of premature ventricular contraction, premature ventricular complexes (PVC) with class I antiarrhythmi ... References Antiarrhythmic agents Benzanilides 4-Methoxyphenyl compounds Piperidines Sodium channel blockers Withdrawn drugs {{cardiovascular-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart Ischemia
Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue, i.e., hypoxia and microvascular dysfunction. It also implies local hypoxia in a part of a body resulting from constriction (such as vasoconstriction, thrombosis, or embolism). Ischemia causes not only insufficiency of oxygen but also reduced availability of nutrients and inadequate removal of metabolic wastes. Ischemia can be partial (poor perfusion) or total blockage. The inadequate delivery of oxygenated blood to the organs must be resolved either by treating the cause of the inadequate delivery or reducing the oxygen demand of the system that needs it. For example, patients with myocardial ischemia have a decreased blood flow to the heart and are prescribed with me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinical Trials Related To Cardiology
Clinical may refer to: Healthcare * Of or about a clinic, a healthcare facility * Of or about the practice of medicine Other uses * ''Clinical'' (film), a 2017 American horror thriller See also * * * Clinical chemistry, the analysis of bodily fluids for diagnostic and therapeutic purposes * Clinical death, the cessation of blood circulation and breathing * Clinical formulation, a theoretically-based explanation of information obtained from clinical assessment * Clinical governance, a systematic approach to maintaining and improving the quality of patient care * Clinical linguistics, linguistics applied to speech-language pathology * Clinical psychology, the understanding, preventing, and relieving psychologically-based distress or dysfunction * Clinical research, to determine the safety and effectiveness of medications etc. * Clinical significance, the practical importance of a treatment effect * Clinical trial, experiments or observations done in clinical research * Clinical w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
