Ventricular tachyarrhythmia, treatment

Ventricular fibrillation should be terminated by electrical defibrillation. Alternatively, lidocaine can be injected intravenously. In cases with lower frequency, ventricular tachyarrhythmia class I diugs such as aj marine, flecainide or propafenone are more effective as a result of the use-dependence of lidocaine. For prophylaxis treatment, amiodarone or sotalol may be helpful or the implantation of a cardioverter-defibrillator system. Acute amiodarone (i.v. in higher doses) can also terminate ventricular tachyarrhythmias. This action, however, seems to be mediated by its INa-blocking side effects and not (or less) by its class III like effects. 

Higgins SL, Hummel JD, Niazi IK, et al. Cardiac resynchronization therapy for the treatment of heart failure in patients with intraventricular conduction delay and malignant ventricular tachyarrhythmias, [see comment]. J. Am. Coll. Cardiol. 2003 42 1454-9. 

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. 

Class Ill-agents, used clinically, are rare, with amiodarone as the best-known example. Several experimental preparations are the subject of clinical investigation. Amiodarone has shown to be effective in the treatment of various ventricular tachyarrhythmias and one of its major advantages is... 

II.b.2.1. Prokinetic agents. Cisapride cisapride treatment can be demonstrated to improve sphincter and motor function and to improve modestly the symptoms of heartburn. However, it is relatively ineffective in severe disease, and adverse effects of impaired intracardiac electrical conduction causing ventricular tachyarrhythmias have resulted in its withdrawal from general use. 

It is indicated in prophylaxis or treatment of ventricular arrhythmias associated with Ml, digitalis intoxication, ventricular tachyarrhythmia, in patients predisposed to ventricular arrhythmias during general anaesthesia. 

These are class IC drugs with similar pharmacological profiles and with the same indication range and adverse effects. They are mainly used for the treatment of severe, lifethreatening ventricular tachyarrhythmias, and non-sustained ventricular tachycardia or high-frequency premature ventricular beats. The main adverse effects are cardiovascular, including proarrhythmic actions and severe negative inotropic effects, especially in patients with impaired cardiac function. Both flecainide and encainide increase the risk of sudden death in patients with myocardial infarction and asymptomatic unsustained ventricular arrhythmias. 

Therapeutic uses Quinidine is used in the treatment of a wide variety of arrhythmias, including atrial, AV junctional, and ventricular tachyarrhythmias. Quinidine is used to maintain sinus rhythm after direct current cardioversion of atrial flutter or fibrillation and to prevent frequent ventricular tachycardia. 

These are Class IB drugs with actions similar to those of lidocaine. These agents can be administered orally. Mexiletine [mex IL e teen] is used for chronic treatment of ventricular arrhythmias associated with previous myocardial infarction. Tocainide [toe KAY nide] is used for treatment of ventricular tachyarrhythmias. Tocainide has pulmonary toxicity, which may lead to pulmonary fibrosis. 

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

Kovoor P, Eipper V, Byth K, Cooper MJ, Uther JB, Ross DL. Comparison of sotalol with amiodarone for long-term treatment of spontaneous sustained ventricular tachyarrhythmia based on coronary artery disease. Eur Heart J 1999 20(5) 364-74. 

Saoudi N, Rinaldi JP, Yaici K, Bergonzi M. Dofetihde what role in the treatment of ventricular tachyarrhythmias Eur Heart J 2001 22(23) 2141-3. 

Nattel S and Mittleman M (1984) Treatment of ventricular tachyarrhythmias resulting from amitriptyline toxicity in dogs. Journal of Pharmacology and Experimental Therapeutics 231 430—435. 

Procainamide is used for the treatment of ventricular tachyarrhythmia. Its therapeutic range is 4-8 pg mL and it is administered intravenously as well as by extravascular routes. The elimination half life and the apparent volume of distribution of procainamide are reported to be 3 h and 2L kg , respectively. 

Procainamide is used for the treatment of ventricular tachyarrhythmia. It is administered intravenously, orally and intramuscularly, and its therapeutic range is 4 to 8pgmL . When a 750 mg dose is administered intravenously to a normal healthy subject ... 

Some commercially available implantable devices for the treatment of congestive heart failure and/or ventricular tachyarrhythmias now continually monitor intrathoracic impedance and display fluid status trends. This information is then provided to the clinician via direct device interrogation or by remote telemetry. Recent reports based on actual clinical experience with this feature have attested to critical reliability and utility (Vollmann et al., 2007) and good correlation with other traditional tools such as brain natriuretic peptide (Luthje et al., 2007). 

As early as the late 1700s, Physicians speculated that electrical current could be used to stimulate the heart. In 1882, von Ziemssen used electrical current to directly stimulate the heart of a woman whose anterior chest wall had been removed after resection of a chest tumor. In 1952, ZoU used transthoracic current to pace the heart, and in 1958 the first implantable pacanaker was placed by Ake Senning and Rune Elmquist. At the same time, Furman and Robinson demonstrated the feasibility of transvenous cardiac pacing. In the late 1960s, Mirowski and colleagues pioneered the concept of an implantable device that could be used to defibrillate the heart. Over the last 50 years, implantable cardiac devices have become the primary treatment for bradyarrhythmias and ventricular tachyarrhythmias and have emerged as an important adjunctive therapy for patients with heart failure. It is currently estimated that almost 400,000 pacemakers and defibrillators are implanted annually in the United States. 

Totterman KJ, Tuito H, PelUnen T (1982) Overdrive pacing as treatment of sotalol-induced ventricular tachyarrhythmias (torsade de pointes). Acta Med Scand Suppl 668 28-33 Tsutsui K, Hayami N, Kunishima T et al (2012) Dexmedetomidine and clonidine inhibit ventricular tachyarrhythmias in a rabbit model of acquired long QT syndrome. Circ J 76 2343-2347 Turner JR (2010) New drug development an introduction to clinical trials, 2nd edn. Springer, New York... 

Berberine has been used in the treatment of several heart diseases including hypertension and arrhythmia in folk medicine [46, 47]. Several pharmacological studies have shown the beneficial effects of berberine oti diverse cardiovascular disorders in animal and human, including prevention of ischemia-induced ventricular tachyarrhythmia, improvement of cardiac contractile function, and reductirMi of peripheral vascular resistance and blood pressure [48, 49]. Berberine has also positive inotropic, negative chronotropic, antiarrhythmic, vasodilator, and antiatherosclerosis properties [50]. 

The effect of magnet placement on an ICD is quite different from that on a pacemaker. For the contemporary ICD, pacing function remains imaltered. The detection of ventricular tachyarrhythmias, and thus delivery of treatment, maybe turned OFF As such, only individuals experienced with this maneuver should perform magnet application. Depending on the manufacturer, this feature may be automatic with magnet application or occur only after a programming maneuver has "enabled" a magnet effect to occur. 

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. 

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. 

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. 

It is indicated in tachyarrhythmias associated with WPW syndrome, atrial flutter and fibrillation, paroxysmal tachyarrhythmias not responding to other agents. Ventricular tachycardia and ventricular arrhythmia refractory to other 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... 

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. 

Propranolol has been reported to exhibit quinidine-like antiarrhythmic actions which are quiet independent of beta-adrenergic blockade. Hence, these pharmacological properties are usually employed to suppress ventricular tachycardia, digitalis-induced tachyarrhythmias, paroxysml atrial tachycardia, and lastly ventricular and atrial extra-systoles. It is also currently receiving a lot of attention in the treatment and management of essential hypertension. 

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. 

This phenomenon represents one of the other significant pacemaker/ICD interactions that can occur besides undersensing of VF. In fact if the atrial and ventricular pacing spikes are sensed at a fast enough rate the ICD can detect what it thinks is a tachyarrhythmia and deliver treatment. 

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