Cardiac arrhythmias treatment

Untoward effects of both E and NE (usually to a lesser degree) are anxiety, headache, cerebral hemorrhage (from vasopressor effects), cardiac arrhythmias, especially in presence of digitaUs and certain anesthetic agents, and pulmonary edema as a result of pulmonary hypertension. The minimum subcutaneous lethal dose of E is about 4 mg, but recoveries have occurred after accidental overdosage with 16 mg subcutaneously and 30 mg intravenously, followed by immediate supportive treatment. 

These dm are primarily used in the treatment of hypertension (see the Summary Drug Table Adrenergic Blocking Drugs also see Chap. 39) and certain cardiac arrhythmias (abnormal rhythm of the heart), such as ventricular arrhythmias or supraventricular tachycardia They are used to prevent reinfarction in patients with a recent myocardial infarction (1—4 weeks after MI). Some of these dm have additional uses, such as the use of propranolol for migraine headaches and nadolol for angina pectoris. 

Antiadrenergic drag s are used mainly for the treatment of certain cardiac arrhythmias and hypertension (see the Summary Drug Table Adrenergic Blocking Dmgp). 

When propranolol is administered orally for a less serious cardiac arrhythmia, cardiac monitoring is usually not necessary. The nurse should monitor the patient s blood pressure and pulse rate and rhythm at varying intervals, depending on the length of treatment and the patient s response to the drug. 

The cardiotonics are used to treat HF and atrial fibrillation. Atrial fibrillation is a cardiac arrhythmia characterized by rapid contractions of the atrial myocardium, resulting in an irregular and often rapid ventricular rate. See Chapter 40 for more information on various arrhythmias and treatment. 

Animal studies indicate that trichloroethylene can sensitize the heart to epinephrine-induced arrhythmias. Other chemicals can affect these epinephrine-induced cardiac arrhythmias in animals exposed to trichloroethylene. Phenobarbital treatment, which increases the metabolism of trichloroethylene, has been shown to reduce the trichloroethylene-epinephrine-induced arrhythmias in rabbits (White and Carlson 1979), whereas high concentrations of ethanol, which inhibits trichloroethylene metabolism, have been found to potentiate trichloroethylene-epinephrine-induced arrhythmias in rabbits (White and Carlson 1981). These results indicate that trichloroethylene itself and not a metabolite is responsible for the epinephrine-induced arrhythmias. In addition, caffeine has also been found to increase the incidence of epinephrine-induced arrhythmias in rabbits exposed to trichloroethylene (White and Carlson 1982). 

The treatment goals for acute intoxication of ethanol, cocaine/amphetamines, and opioids include (1) management of psychological manifestations of intoxication, such as aggression, hostility, or psychosis, and (2) management of medical manifestations of intoxication such as respiratory depression, hyperthermia, hypertension, cardiac arrhythmias, or stroke. 

In the periphery, 5-HT4 receptor mRNA is found in vascular smooth muscle. Newly developed drugs that activate 5-HT4 receptors are of interest for their potential in treating cardiac arrhythmia. The 5-HT4 receptor is also located on neurons of the alimentary tract, for example the myenteric plexus of the ileum, and on smooth muscle cells and secretory cells of the gastrointestinal tract, where they evoke secretions and the peristaltic reflex. 5-HT4 receptor agonists (e.g. cisapride, prucalopride, tegaserod) are used therapeutically in the treatment of constipation-predominant irritable bowel syndrome and in functional motility disorders of the upper gastrointestinal tract. 

High risk Has unstable or symptomatic angina, despite treatment Has uncontrolled hypertension Has severe congestive heart failure (NYHA class III or IV) Had a recent myocardial infarction or stroke within past 2 weeks Has moderate or severe valvular heart disease Has high-risk cardiac arrhythmias Has obstructive hypertrophic cardiomyopalhy Phosphodiesterase inhibitor is contraindicated sexual intercourse should be deferred... 

Other phenol-containing products are used as chemical peels to remove skin lesions, and in the treatment of chronic pain or spasticity. These uses have occasionally been associated with adverse outcomes, like cardiac arrhythmias, that have been seen in both adults and children. 

The [ -adrenoreceptors antagonists (also called [)-blockers) comprise a group of chiral drugs that are mostly used in the treatment of cardiovascular disorders such as hypertension, cardiac arrhythmia, or ischemic heart disease. Teicoplanin is the chiral selector most exploited for the enantioseparation of this class of compounds, followed by vancomycin. Several P-blockers have been analyzed, particularly in the... 

Hill. J.L. (1985) in Mechanism and Treatment of Cardiac Arrhythmias Relevance of Basic Studies to Clinical Management (Reiser, H.J. and Horowitz, L.N., eds.), pp. 173-182, Urban Schwarzenberg, Baltimore. 

Of greater concern is the safety of the TCAs. Toxic levels of these medications can produce lethal cardiac arrhythmias, seizures, and suppression of breathing. An overdose of a 1-2 week supply of most TCAs is often fatal, a serious consideration when prescribing medication to depressed patients with suicidal thoughts. Children taking imipramine for treatment of ADHD have died from sudden cardiac death consequently, child psychiatrists seldom use TCAs. Likewise, patients with heart disease or seizure disorders are more likely to have dangerous complications from TCAs and should avoid them. 

During the initial evaluation, providing for the safety of the patient is of paramount importance. The severity of intoxication and potential for withdrawal must be quickly and accurately determined. Extreme alcohol intoxication can be fatal either by the production of cardiac arrhythmias, aspiration (the inhalation of stomach contents that are vomited), or other causes. We have all seen reports of college students dying from alcohol poisoning. Likewise, up to 10% of patients in severe alcohol withdrawal can die without treatment. Fortunately, most patients do not experience the most severe forms of alcohol withdrawal such as the DTs. Mild withdrawal can be managed in the outpatient setting with appropriate support and patient adherence, but severe withdrawal requires an inpatient hospitalization. See Section 6.5 for further discussion of the initial evaluation. 

Cardiostimulation. By stimulating Pi-receptors, hence activation of ade-nylatcyclase (Ad-cyclase) and cAMP production, catecholamines augment all heart functions, including systolic force (positive inotropism), velocity of shortening (p. clinotropism), sinoatrial rate (p. chronotropism), conduction velocity (p. dromotropism), and excitability (p. bathmotropism). In pacemaker fibers, diastolic depolarization is hastened, so that the firing threshold for the action potential is reached sooner (positive chronotropic effect, B). The cardiostim-ulant effect of p-sympathomimetics such as epinephrine is exploited in the treatment of cardiac arrest Use of p-sympathomimetics in heart failure carries the risk of cardiac arrhythmias. 

Many local anesthetics have a selective depressant action on heart muscle when given systemically. This is useful in treatment of cardiac arrhythmias, and a lidocaine-like drug with this kind of action is tocainide (2). ... 

Phenytoin, introduced as an anticonvulsant drug in 1938, remains one of the drugs most frequently prescribed for convulsive disorders. The precise mode of action is unknown, but it appears to inhibit the accumulation of sodium in nerve cells, thus stabilizing hyperexcitable cell membranes (A13)—a property also utilized in the treatment of cardiac arrhythmias. 

Cardiac glycosides are drags used in the treatment of congestive heart failure or cardiac arrhythmia, by inhibiting the Na+/K+ pump. This inhibition increases the amount of Ca + ions available for contraction and improves cardiac output and reduces distention of the heart. Cardiac glycosides are extracted from plant material. 

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