Complete heart block

Complete Heart Block No PbTx Antibody Treatment (Lead VIO. 1 cm/mv. 25 mm/sec)... 

In third-degree AV nodal blockade, or complete heart block, the heart rate is usually 30 to 40 bpm, resulting in symptoms. 

The sequence of cardiovascular signs as serum magnesium increases from 3 mEq/L to 15 mEq/L is hypotension, cutaneous vasodilation, QT-interval prolongation, bradycardia, primary heart block, nodal rhythms, bundle branch block, QRS- and then PR-interval prolongation, complete heart block, and asystole. 

The a wave This is caused by atrial contraction and is, therefore, seen before the carotid pulsation. It is absent in atrial fibrillation and abnormally large if the atrium is hypertrophied, for example with tricuspid stenosis. Cannon waves caused by atrial contraction against a closed tricuspid valve would also occur at this point. If such waves are regular they reflect a nodal rhythm, and if irregular they are caused by complete heart block. 

Cardiovascular Effects. Epidemiologic studies indicate that chloroform causes cardiac efiects in patients under anesthesia. In a cohort of 1,502 patients (exposure less than 22,500 ppm), dose-related bradycardia developed in 8% of the cases, and cardiac arrhythmia developed in 1.3% of the cases (Whitaker and Jones 1965). Hypotension was observed in 27% of the patients and was related to the duration of the anesthesia and to pretreatment with thiopentone. Chloroform anesthesia (exposure 8,000-10,000 ppm) caused arrhythmia (nodal rhythm, first degree atrio-ventricular block, or complete heart block) in 50% of the cases from the cohort of 58 patients and hypotension in 12% (Smith et al. 

With severe intoxication by all routes, an excess of acetylcholine at the neuromuscular junctions of skeletal muscle causes weakness aggravated by exertion, involuntary twitchings, fasciculations, and eventually paralysis. The most serious consequence is paralysis of the respiratory muscles. Effects on the central nervous system include giddiness, confusion, ataxia, slurred speech, Cheyne-Stokes respiration, convulsions, coma, and loss of reflexes. The blood pressure may fall to low levels, and cardiac irregularities, including complete heart block, may occur. ... 

Sinus node disease andAVbiock The drug may cause severe sinus bradycardia or sinoatrial block in patients with preexisting sinus node disease and may cause advanced or complete heart block in patients with preexisting incomplete AV block. Consider inserting a pacemaker before treatment with digoxin. 

Oral Premature atrial, AV junctional and ventricular contractions paroxysmal atrial (supraventricular) tachycardia paroxysmal AV junctional rhythm atrial flutter paroxysmal and chronic atrial fibrillation established atrial fibrillation when therapy is appropriate paroxysmal ventricular tachycardia not associated with complete heart block maintenance therapy after electrical conversion of atrial fibrillation or flutter. Parenteral When oral therapy is not feasible or when rapid therapeutic effect is required. 

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. 

Complete heart block idiosyncratic hypersensitivity lupus erythematosus torsades... 

In sinus bradycardia or incomplete heart block, lidocaine administration for the elimination of ventricular ectopy without prior acceleration in heart rate (eg, by atropine, isoproterenol or electric pacing) may promote more frequent and serious ventricular arrhythmias or complete heart block. Use with caution in patients with hypovolemia and shock, and all forms of heart block. 

Preexisting second- or third-degree AV block, right bundle branch block when associated with a left hemiblock (bifascicular block), unless a pacemaker is present to sustain the cardiac rhythm if complete heart block occurs recent myocardial infarction (Ml) presence of cardiogenic shock hypersensitivity to the drug. 

Goldberg RJ, Zevallos JC, Yarzebski J, et al. Prognosis of acute myocardial infarction complicated by complete heart block (the Worcester Heart Attack Study). Am. J. Cardiol. 1992 69 1135-41. 

Acute cardiovascular reactions to procainamide administration include hypotension, A-V block, intraventricular block, ventricular tachyarrhythmias, and complete heart block. The drug dosage must be reduced or even stopped if severe depression of conduction (severe prolongation of the QRS interval) or repolarization (severe prolongation of the QT interval) occurs. 

Complete heart block following closure of ventricular septal defects IV 0 04-0 06 mg (2-3 ml of diluted solution). 

Contraindications Complete heart block, myasthenia gravis, preexisting QT prolongation, second-degree heart block, systemic lupus erythematosus, torsades de pointes... 

Maintenance of normal sinus rhythm after conversion of atrial fibrillation or flutter, prevention of premature atrial, AV, and ventricular contractions paroxysmal atrial tachycardia paroxysmal AV functional rhythm atrial fibrillation atrial flatter paroxysmal ventricular tachycardia not associated with complete heart block PO 100-600 mg q4-6h. (Long-acting) 324-972 mg q8-12h. IV 200-400 mg. 

Cardiac uses Adrenaline may be used to stimulate the heart in cardiac arrest. Adrenaline can also be used in Stokes-Adam syndrome, which is a cardiac arrest occurring at the transition of partial to complete heart block. Isoprenaline or orciprenaline maybe used for the temporary treatment of partial or complete AV block. 

Catecholamines such as isoproterenol and epinephrine have been used in the temporary emergency management of complete heart block and cardiac arrest. Epinephrine may be useful in cardiac arrest in part by redistributing blood flow during cardiopulmonary resuscitation to coronaries and to the brain. However, electronic pacemakers are both safer and more effective in heart block and should be inserted as soon as possible if there is any indication of continued high-degree block. 

Kearns-Sayre syndrome [17] A multisystem disorder characterized by the invariant triad onset before age 20 years, PEO, pigmentary retinal degeneration plus at least one of the following complete heart block, cerebrospinal fluid protein above 100 mg/dl, cerebellar ataxia. Large-scale heteroplasmic mitochondrial DNA deletions are frequently detected in skeletal muscle (rarely in other tissues). 

Procainamide (Pronestyl, Pronestyl SR, Procanbid) [Antiarrhythmic] WARNING Only use in life-treating arrhythmias hematologic tox can be severe Uses Supraventricular/ventricular arrhythmias Action Class 1A antiarrhythmic (Table VI-7) Dose Adults. Recurrent VF/pulseless VT 20 mg/min slow IV inf to a max of 17 mg/kg or until QRS T by 50% or dysrhythmia resolves Maint inf 4 mg/min (mix 1 gm in 250 mL NS to make 4 mg/mL use 60 gtt set—60 gtt/min = 4 mg) Peds. Loading dose 15-50 mg/kg IV/IO Caution [C, +] Contra Complete heart block, 2nd- or 3rd-degree heart block w/o pacemaker, torsades de pointes, SLE Disp Tabs caps 250, 500 mg SR tabs 500, 750, 1000 mg inj 100, 500 mg/mL SE 1 BP, lupus-like synd, GI upset, taste perversion, arrhythmias, tach, heart block, angioneurotic edema, blood dyscrasias Interactions T Effects W/ acetazolamide, amiodarone, cimetidine, ranitidine, trimethoprim T effects OF anticholinergics, antihypertensives i effects W/ procaine, EtOH EMS Monitor BP and ECG use caution to prevent rapid... 

A 38-year-old woman developed complete heart block, ventricular fibrillation, and subsequent asystole about 7 minutes after intravenous sulprostone 30 micrograms over 5 minutes, after she had previously been given a total dose of intramyometrial sulprostone 500 micrograms at seven different points for postpartum hemorrhage after cesarean section (5). 

A 51-year-old white woman developed severe weakness, near syncope, shortness of breath, and chest pain. She had complete heart block. The creatine kinase activity was over 7000 U/l. She had taken atorvastatin... 

Case (vi) A 75-year-old man suffering from stokes Adams Syndrome (complete heart block). Symptoms Irregular heart beat with omission every 3/4 beats, sunken eyes, unconsciousness with intermittent convulsion. 

Ephedrine, given im/iv/sc, is indicated for the treatment of acute hypotensive states, treatment of Adams-Stokes syndrome with complete heart block, stimulation of the central nervous system (CNS) to combat narcolepsy and depressive states, treatment of acute bronchospasm, treatment of enuresis, and treatment of myasthenia gravis. When given in nasal form, ephedrine is used in the treatment of nasal congestion, promotion of nasal or sinus drainage, or relief of eustachian tube congestion. 

In complete heart block with Stokes-Adams syncope, ephedrine may prove of value in a manner similar to epinephrine. In the attempt to increase ventricular rate and prevent ventricular asystole, an initial dose of about 8 mg of ephedrine sulfate orally may be tried. Later, the dosage may be increased to 25 mg three or four times daily. Syncope due to ventricular tachycardia can also be prevented in some cases with ephedrine. 

B35. Buyon, J. P., and Winchester, R., Congenital complete heart block. A human model of passively acquired autoimmune injury. Arthritis Rheum. 33,609-614 (1990). 

R7. Reichlin, M., Brucato, A., Frank, M. B., Maddison, P. J., McCubbin, V. R., etal., Concentration of autoantibodies to native 60-kd Ro/SS-A and denatured 52-kd Ro/SS-A in eluates from the heart of a child who died with congenital complete heart block. Arthritis Rheum. 37,1698-1703 (1994). 

Possible complications include massive myocardial infarction due to retrograde flow around the occlusion balloon, complete heart block, ventricular fibrillation, stroke, dissection of the left anterior descending artery, and right coronary artery thrombosis. Though high grade atrioventricular blockage occurs relatively frequently, procedural mortality rate is low (0-4%) and severe complications are rare and often avoidable (7-10). 

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