Atrial tachyarrhythmias

Implantable tachyrhythmia devices, available for some years, address far less dangerous atrial tachyarrhythmias and fibrillation. The technical barriers to counteracting ventricular tachyarrhythmias and fibrillation using massive shocks have been formidable and are compounded by the possibiUty of causing the very problem the shock is designed to overcome. Newer tachyrhythmia devices are being readied that can safely regulate arrhythmias across the hiU spectmm. 

Bunaftine (21) is a naphthalenecarboxamide derivative, that has been developed as an antiarrhythmic agent. The compound exhibits both Class I and Class III electrophysiological effects. Fenici and co-workers studied bunaftine in patients with paroxysmal atrial tachyarrhythmia and recorded right atrial monophasic action potentials [72]. A mean increase of 18% in atrial repolarization time and an increase in monophasic APD during pac-... 

Atrial tachyarrhythmias Digitalize patients with atrial flutter or fibrillation prior to administration to ensure that enhancement of AV conduction does not increase ventricular rate beyond acceptable limits. 

Manolis AG, Katsivas AG, Lazaris EE, Vassilopoulos CV, Louvros NE. Ventricular performance and quality of life in patients who underwent radiofrequency AV junction ablation and permanent pacemaker implantation due to medically refractory atrial tachyarrhythmias. J. Interv. Card. Electrophysiol. 1998 2 71-6. 

Amiodarone is effective in maintaining sinus rhythm in most patients with paroxysmal atrial hbrillation and in many patients with persistent atrial hbrillation. It is also effective in preventing recurrences of A-V nodal reentry and atrial tachyarrhythmias and in the prevention of reentrant rhythms and atrial hbrillation in patients with Wohf-Parkinson-White syndrome. Also, it is the most efficacious therapy for postoperative junctional ectopic tachycardia. 

Verapamil is useful for slowing the ventricular response to atrial tachyarrhythmias, such as atrial flutter and fibrillation. Verapamil is also effective in arrhythmias supported by enhanced automaticity, such as ectopic atrial tachycardia and idiopathic left ventricular tachycardia. 

The prominent depressant action of verapamil and diltiazem at the SA and A-V nodes finds use in specific arrhythmias. They are of proven efficacy in acute control and long-term management of paroxysmal supraventricular tachycardia (see Chapter 16).Their ability to inhibit conduction at the A-V node is employed in protecting ventricles from atrial tachyarrhythmias, often in combination with digitalis or propranolol. 

Which of the following calcium channel blockers would be most likely to suppress atrial tachyarrhythmias involving the A-V node ... 

Brembilla-Perrot B, Houriez P, Beurrier D, Qaudon O, Terrier de la Chaise A, Louis P. Predictors of atrial flutter with 1 1 conduction in patients treated with class I antiarrhythmic drugs for atrial tachyarrhythmias. Int J Cardiol 2001 80(1) 7-15. 

Babuty D, Maison-Blanche P, Fauchier L, Brembilla-Perrot B, Medvedowsky JL, Bine-Scheck F. Double-blind comparison of cibenzoline versus flecainide in the prevention of recurrence of atrial tachyarrhythmias in 139 patients. Ann Noninvasive Electrocardiol 1999 4 53-9. 

Rae AP, Camm J, Winters S, Page R. Placebo-controlled evaluations of propafenone for atrial tachyarrhythmias. Am J Cardiol 1998 82(8A) N59-65. 

Class IV is used for atrial tachyarrhythmias and contains certain CALCIUM-CHANNEL BLOCKERS, e g. diltiazcm and verapamil. 

An important step in symptom-targeted therapy that acts to decrease pulmonary venous pressures is to maintain atrial contraction and atrioventricular (AV) synchrony. Maintaining atrial contraction and AV synchrony is important both in preserving normal cardiac output and in keeping LV diastolic pressure low. Chemical or electrical cardioversion of persistent atrial tachyarrhythmias will decrease diastolic pressure, increase cardiac output, and resolve pulmonary edema. An AV sequential pacemaker should be used to treat bradyarrhythmias in patients requiring pacing. 

The use of propranolol (Inderal) as an antiarrhythmic is useful in the treatment of atrial tachyarrhythmias. Its mechanism is somewhat controversial. Since propranolol is a (3-adrenergic blocking agent, it seems logical to study this feature. The drug can be shown to block the cardiac effects of catecholamines. The effective refractory period of the AV node has been shown to increase. However, some quinidinelike properties have also been observed. The suggestion has been made that the antiarrhythmic action is caused by interference with the cellular transport of Ca2+. 

In patients with diabetes mellitus, niacin should be used cautiously, since niacin-induced insulin resistance can cause severe hyperglycemia. Niacin use in patients with diabetes mellitus often mandates a change to insulin therapy. If niacin is prescribed for patients with known or suspected diabetes, blood glucose levels should be monitored at least weekly until proven to be stable. Niacin also elevates uric acid levels a history of gout is a relative contraindication for niacin use. Rarer reversible side effects include toxic amblyopia and toxic maculopathy. Atrial tachyarrhythmias and atrial fibrillation have been reported, more commonly in elderly patients. Niacin, at doses used in humans, has been associated with birth defects in animal models and should not be taken by pregnant women. 

Quinidine (e.g., Cin-Quin) Depresses automaticity of ectopic foci. Siows conduction veiocity in atria His-Purkinje ceils. Prolongs refractory period throughout heart (except nodes) and accessory pathways. Has anticholinergic effects which may actuaiiy enhance A-V conduction in patients with rapid atrial depolarization. Multifocal atrial tachycardia, premature atrial depolarization, premature ventricular depolarization, atrial fibrillation (these result from increased automaticity of ectopic foci), and ventricular tachycardia. Torsades de pointes (recurrent, temporary arrhythmia), increases ventricle response to atrial tachyarrhythmia, nausea, vomiting, diarrhea, hypersensitivity, cinchonism, thrombocytopenic purpura. 

There is also some evidence that, in the treatment of resistant atrial tachyarrhythmias, the risk of arrhythmias may be increased by the concurrent use of digoxin and amiodarone,and another study found that combined use had an unfavourable effect on survival in patients with atrial fibrillation and sinus rhythm. ... 

Tandeter H, Kobal S, Katz A. Swallowing-induced atrial tachyarrhythmia triggered by salbutamol case report and review of the literature. Clin Cardiol 2010 33(6) El 16-20. 

VDI is used infrequently as a permanent mode however, some devices mode switch to VDI or VDIR. It has the same function as the VVI mode but with atrial sensing capability for diagnostic purposes (e.g., counting episodes of atrial tachyarrhythmias). Pacing only occurs in the ventricle while sensing occurs in both the atrium and ventricle. 

The DVI mode provides pacing in the atrium and the ventricle, but sensing occurs only in the ventricle (Fig. 3.8). Therefore, like the DDI mode, atrial tracking does not occur. However, unlike DDI, atrial events do not inhibit atrial output. Because atrial output occurs without regard to intrinsic atrial activity, in the DVI mode atrial pacing after an intrinsic atrial event may precipitate an atrial tachyarrhythmia. This pacing mode is essentially obsolete. 

To do a tnalpositioned atrial septal lead can be deleterious, possibly causing pacemaker syndrome or, if high-rate atrial tachyarrhythmia therapy pacing is used, may result in inappropriate, dangerously high ventricular rates. 

Gillis AM, Unterbeig-Buchwald C, Schmidinger H, Massimo S, Wolfe K, Kavaney DJ, Ottemess ME, Hohnloser SH. Safety and efftcacy of advanced atrial pacing therapies for atrial tachyarrhythmias in patients with a new implantable dual chamber cardioverter-defibiillator. 7 Am Coll Cardiol. 2002 40 1653-1659. 

Padeletti L, Purerfellner H, Adler SW, Waller TJ, Harvey M, Horvitz L, Holbrook R, Kempen K, Mugglin A, Hettrick DA. Combined efficacy of atrial septal lead placement and atrial pacing algorithms for prevention of paroxysmal atrial tachyarrhythmia. J Cardiovasc Electrophysiol. 2003 14 1189-1195. 

Kamalvand K, Tan K, Kotsakis A, Bucknall C, Sulke N. Is mode switching beneficial A randomized study in patients with paroxysmal atrial tachyarrhythmias. J Am Coll Cardiol. 1997 30 496-504. 

Savelieva I, Camm AJ. The results of pacing trials for the prevention and termination of atrial tachyarrhythmias is there any evidence of therapeutic breakthrough J Interv Card Electrophysiol 2003 8 103-15. 

Purerfellner H, Ruiter JH, Widdershoven JW, et al. Reduction of atrial tachyarrhythmia episodes during the overdrive pacing period using the post-mode switch overdrive pacing (PMOP) algorithm. Heart Rhythm 2006 3 1164-71. 

Israel CW, Ehrlich JR, Gronefeld G, et al. Prevalence, characteristics and clinical implications of regular atrial tachyarrhythmias in patients with atrial fibrillation insights from a study using a new implantable device. J Am CoU Cardiol... 

Lee MA, Weachter R, Poliak S, et al. The effect of atrial pacing therapies on atrial tachyarrhythmia burden and frequency results of a randomized trial in patients with bradycardia and atrial tachyarrhythmias. J Am Coll Cardiol... 

Mabo P and the Leaf Study Group. The LEAF (Loe Energy in Atrial FibriUation) study results Evaluation of device based therapies for atrial tachyarrhythmia prevention and termination. Heart Rhythm 2005 2 S17. 

Gillis AM, Koehler J, Morck M, et al. High atrial antitachycardia pacing therapy efficacy is associated with a reduction in atrial tachyarrhythmia burden in a subset of patients with sinus node dysfunction and paroxysmal atrial fibrillation. Heart Rhythm 2005 2 791-6. 

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