Supraventricular tachyarrhythmia treatment

Dmgs that mimic or inhibit the actions of neurotransmitters released from parasympathetic or sympathetic nerves innervating the heart may also be used to treat supraventricular bradyarrhythmias, heart block, and supraventricular tachyarrhythmias. Those used in the treatment of arrhythmias may be found in Table 1. 

Phenylephrine. Phenylephrine hydrochloride is an a -adrenoceptor agonist. Phenylephrine produces powerful vasoconstrictor and hypertensive responses. This results in baroreceptor activation of a reflex bradycardia and thus is useful in the treatment of supraventricular tachyarrhythmias. Unlike epinephrine [51-43-4] the actions of which are relatively transient, phenylephrine responses are more sustained (20 min after iv dosing and 50 min after subcutaneous dosing) (86). 

Class IV antiarrhythmic drugs are Ca2+ channel blockers, which predominantly slow sinus rate and atrioventricular conduction and thus are used in the treatment of supraventricular tachyarrhythmias. These drugs exert a pronounced negative inotropic effect. 

Indications. Verapamil is used as an antiarrhythmic drug in supraventricular tachyarrhythmias. In atrial flutter or fibrillation, it is effective in reducing ventricular rate by virtue of inhibiting AV-conduction. Verapamil is also employed in the prophylaxis of angina pectoris attacks (p. 308) and the treatment of hypertension (p. 312). Adverse effects Because of verapamil s effects on the sinus node, a drop in blood pressure fails to evoke a reflex tachycardia Heart rate hardly changes bradycardia may even develop. AV-block and myocardial insufficiency can occur. Patients frequently complain of constipation. 

Inappropriate sinus bradycardia, sinoatrial block, and bradycardia-tachycardia syndrome (bradycardia followed by supraventricular tachyarrhythmias such as atrial fibrillation) are included in this syndrome. Treatment of sick sinus syndrome is generally based upon the patients symptoms. In general, bradycardia... 

Esmolol is used in the treatment of supraventricular tachyarrhythmias for rapid control of ventricular rate and reduction of myocardial oxygen consumption. Discontinuation of administration is followed by a rapid reversal of its pharmacological effects because of es-molol s rapid hydrolysis by plasma esterases. 

Dofetilide is approved for the treatment of atrial fibrillation and atrial flutter. Because of the lack of significant hemodynamic effects, dofetilide may be useful in patients with CHF who are in need of therapy for supraventricular tachyarrhythmias. Dofetilide is not indicated for use in the setting of ventricular arrhythmias. 

Kopehnan HA, Horowitz LN. Efficacy and toxicity of amiodarone for the treatment of supraventricular tachyarrhythmias. Prog Cardiovasc Dis 1989 31(5) 355-66. 

Digoxin, the most commonly used cardiac glycoside, is indicated for the treatment of CHF and for the treatment of supraventricular tachyarrhythmias. It possesses positive inotropic and electro-physiological effects resulting from the inhibition of Na, K -ATPase, which increases intracellular sodium ion concentrations. This increase in intracellular sodium ions slows down calcium extrusion from the cell, resulting in an increase in intracyto-plasmic calcium and, thereby, an increase in the contractile force. 

Esmeron rocuronium bromide, esmolol [BAN, inn] (esmolol hydrochloride [usan] Brevibloc Celectol ) is a P-adrenoceptor antagonist, which is relatively water-soluble. Therapeutically, it can be used as an antiarrhythmic to control supraventricular tachyarrhythmias, as an antihypertensive and antiglaucoma treatment. 

Quinidine, available as either quinidine sulfate or quinidine gluconate, is used in the treatment of atrial premature contraction, paroxysmal supraventricular tachycardia, supraventricular tachyarrhythmia, PVCs, and ventricular tachycardia and in prophylactic treatment after myocardial infarction. It is also used with care in the treatment of atrial... 

It is important to recognize that an ICD should be considered for long-term rhythm management, not for acute treatment. As such, patients should not undergo implant of an ICD if ventricular arrhythmias are incessant or frequent or if supraventricular tachyarrhythmias are not well controlled. Any patient for whom an ICD implant is considered should have myocardial ischemia and heart failure controlled as best possible first. All other potential complicating medical problems should be addressed before delving into an implant. 

Blockers are antiarrhythmics of class II according to the Vaughan-Williams classification, effective in the treatment of both supraventricular and ventricular tachyarrhythmias. These drugs can also reduce ectopic beats, especially if they are a result of sympathetic activity. Sotalol is a racemic mixture of the -blocking L-isomer and the class III antiarrhythmic D-isomer. This racemic mixture as well as D-sotalol are used as class Ill-antiarrhythmic. 

Clinically, tachyarrhythmias associated with digitalis excess (including supraventricular and ventricular extrasystoles) and ventricular tachycardia have been suppressed by propranolol. Although propranolol is highly effective in the treatment of digitalis-induced arrhythmias, phenytoin and Udocaine are preferred. 

Therapeutic uses Amiodarone is effective in the treatment of severe refractory supraventricular and ventricular tachyarrhythmia. Its clinical usefulness is limited by its toxicity. 

Verapamil (80 mg p.o. q. 6 to 8 hours) is indicated in the management of Prinzmetal s or variant angina or unstable or chronic, stable angina pectoris verapamil (0.075 to 0.15 mg/kg rv pnsh over a 2-minnte period) is indicated in the treatment of supraventricnlar tachyarrhythmias verapamil (240 to 480 mg p.o. daily) is indicated in the prevention of recurrent paroxysmal supraventricular tachycardia verapamil (240 to 320 mg p.o. daily) is indicated in the control of the ventricular rate in digitalized patients with chronic atrial flatter and/or fibrillation and verapamil (80 mg p.o. t.i.d.) is indicated in the management of hypertension. 

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