Conduction defects

Peterson I R 1986 A structural study of the conducting defects in fatty acid Langmuir-Blodgett monolayers J. Mol. Electron. 2 95-9... 

EDMD is another X-linked muscular dystrophy, clinically and genetically completely distinct from DMD and BMD. Affected boys usually have onset in childhood of contractures (especially involving the Achilles tendons, elbows, and spinal muscles), humeroperoneal muscle weakness, and cardiac conduction defects, which tend to be mostly a problem in adult life and may necessitate insertion of a pacemaker. The gene for EDMD is known to map to Xq28, but this localization is... 

One eritical factor that has been neglected in considering mechanisms of cardiac fatalities is the timeframe for various types of toxicities. For example, a majority of cocaine-related fatalities and near fatalities reported from emergency rooms are attributed to one or more types of cardiac ischemic or hypertensive episodes (Isner et al. 1986). Thus, these studies may discount the cocaine-induced arrhythmias and conduction defects as important direct causes of fatalities. Yet, if coroner reports are used as data sources (Virmani et al. 1988 Wetli and Wright 1979 Mittleman and Wetli 1984), there are great numbers of deaths in which pulmonary effusion and lack of evidence for coronary occlusion, acute myocardial infarction, or... 

Blockers are contraindicated in patients with severe bradycardia (heart rate less than 50 beats per minute) or AV conduction defects in the absence of a pacemaker. (3-Blockers should be used with particular caution in combination with other agents that depress AV conduction (e.g., digoxin, verapamil, and diltiazem) because of increased risk for bradycardia and heart block. Relative contraindications include asthma, bronchospastic disease, severe depression, and peripheral vascular disease. (3,-Selective blockers are preferred in patients with asthma or chronic obstructive pulmonary... 

A 65-year-old female receives digoxin and furosemide for GIF After several months, she develops nausea and vomiting. Serum K+ is 2.5 mFq/L. Electrocardiogram (EKG) reveals an AV conduction defect. What cellular effect is causing these new findings ... 

Rashes may occur in 10% of patients. Other side effects include hepatitis, osteomalacia, cardiac conduction defects, and lupus-like reactions. 

Hypersensitivity or idiosyncrasy to quinidine or other cinchona derivatives manifested by thrombocytopenia, skin eruption or febrile reactions myasthenia gravis history of thrombocytopenic purpura associated with quinidine administration digitalis intoxication manifested by arrhythmias or AV conduction disorders complete heart block left bundle branch block or other severe intraventricular conduction defects exhibiting marked QRS widening or bizarre complexes complete AV block with an AV nodal or idioventricular pacemaker aberrant ectopic impulses and abnormal rhythms due to escape mechanisms history of drug-induced torsade de pointes history of long QT syndrome. 

Cardiovascular disorders Use with extreme caution in patients with cardiovascular disorders because of the possibility of conduction defects, arrhythmias, CHF, sinus tachycardia. Ml, strokes, and tachycardia. These patients require cardiac surveillance at all dose levels of the drug. In high doses, TCAs may produce arrhythmias, sinus tachycardia, conduction defects, and prolonged conduction time. Tachycardia and postural hypotension may occur more frequently with protriptyline. Hyperthyroid patients Hyperthyroid patients or those receiving thyroid medication require close supervision because of the possibility of cardiovascular toxicity, including arrhythmias. 

Cardiovascular Use with caution in patients with a history of Ml and angina because of the possibility of conduction defects, arrhythmia. Ml, strokes, and tachycardia. 

Rivastigmine Transdermal (Exelon Patch) [Cholinesterase Inhibitor/Anti-Alzheimer Agent] Uses MUd/mod Alzheimer and Parkinson Dz dementia Action Acetylcholinesterase inhibitor Dose Initial 4.6-mg patch/d applied to back, chest, upper arm, T 9.5 mg after 4 wk if tolCTated Caution [ ] Sick sinus synd, conduction defects, asthma, COPD, urinary obst, Sz Contra Hypersensitivity to rivastigmine, other carbamates Disp Transdermal patch 5 cm (4.6 mg/24 h), 10 cm (9.5 mg/24 h) SE NA /D EMS See Rivastigmine OD See Rivastigmine... 

Although much of the data regarding the frequency of conduction abnormalities during acute myocardial infarction were derived from studies prior to the era of rapid reperfusion [14 17], data from more recent trials suggest that the incidence of intraventricular conduction defects has changed very little. 

Contraindications Complete AV block, development of thrombocytopenic purpura during prior therapy with quinidine or quinine, intraventricular conduction defects (widening of QRS complex)... 

An atrioventricular conduction defect Blurred vision Tachypnla... 

Various CNS adverse effects have been reported with CBZ and include sedation, dizziness, ataxia/clumsiness, blurred vision/diplopia, and impaired task performance. Although uncommon, fatal CBZ toxicity does occur. CBZ overdose is characterized by neurological symptoms such as diplopia, dysarthria, ataxia, vertigo, nystagmus, and coma. Infrequently, cyclic coma with biphasic fluctuations of consciousness, seizures, respiratory depression, cardiac conduction defects, and the need for artificial ventilation may occur. Plasma levels are only moderately correlated to severity, but as noted earlier, more than 15 pg/ml in children or 20 pg/ml in adults should be considered serious. Charcoal hemoperfusion or gastric lavage with activated charcoal has been used in such cases, whereas benefit from plasmapheresis is controversial (77, 114, 368). 

HCN4 encodes a pacemaker current in sinoatrial nodal cells mutations in sodium channel gene (SCN5A) cause conduction defects. 

Campos de Carvalho AC, Masuda MO, Tanowitz HB, Wittner M, Goldenberg RC, Spray DC Conduction defects and arrhythmias in Chagas disease Possible role of gap junctions and humoral mechanisms. J Cardiovasc Electrophysiol 1994 5 686-698. 

Local anesthetics block the sodium channels, are cardiac depressants, and bring about a ventricular conduction defect and block that may progress to cardiac and ventilatory arrest if toxic doses are given. In addition, these agents produce arteriolar dilation. Circulatory failure may be treated with vasopressors such as ephedrine, metaraminol (Aramine), or mephentermine (Wyamine). Artificial respiration and cardiac massage may also become necessary. Among the local anesthetics, only cocaine blocks the uptake of norepinephrine, causes vasoconstriction, and may precipitate cardiac arrhythmias. 

Cardiovascular (orthostatic hypotension, conduction defects, arrhythmias)... 

Sertindole. This is structurally unique among the atypical neuroleptics in that it is an indole derivative with a high affinity for 5-HT2A, D2-like (Dj, D3, D4) and also alpha-1 receptors. The antagonistic action on the 5-HT2 receptors probably accounts for its beneficial effects on negative symptoms. Sertindole was suspended from marketing a few years ago because of the rare occurrence of cardiac conduction defects. As the causal relationship of this adverse effect to the drug was never firmly established it is likely to be relaunched in the near future. 

Cardiac conduction defects Muscarinic blockade, Na+ channel blockade Thioridazine, chlorpromazine, sertindole ... 

Conduction defects in BALB/c mice are induced after immunization with 52-kDa Ro (M18). 

D15. Dorner, T., Hiepe, F., Goldner, B., and Apostoloff, E., Investigations into Ro-specific antibody-associated congenital cardiac conduction defects. Clin. Invest. 70, 492-496 (1992). 

Quinine is a cinchona alkaloid that acts rapidly against all four species of Plasmodium. It is used to treat protozoal infections and leg cramps, and as a bitter and flavoring agent. However, the drug is not used prophylactically for malaria. Quinines are contraindicated in patients with a history of hypersensitivity to quinine or quinidine. They should not be used in the presence of hemolysis and should be used with caution in patients with atrial fibrillation, cardiac conduction defects, or heart block. Quinine administration in myasthenia gravis may aggravate the disease, hence it should be avoided. Quinine can be used in pregnancy.37 Intravenous infusion of quinine should be slow, and the patient should be monitored for cardiotoxicity.38 Cinchonism, which is characterized by tinnitus, GI disturbances, and impaired vision may occur with therapeutic doses of quinine.39... 

As well as their effects on the brain, neuroleptics commonly produce other potentially lethal effects. They are all toxic to the heart, inducing conduction defects and arrhythmias. Olanzapine and clozapine also interfere with normal metabolism, causing what is known as metabolic syndrome. This syndrome has only recently been described and is defined as the occurrence of obesity, diabetes, hypertension and dyslipidaemia6 (Shirzadi Ghaemi 2006). The underlying cause of the syndrome is thought to be resistance to insulin. All these effects... 

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