Tachycardia ventricular

Reentry mechanism Intranodal (AV node) reentry Extranodal reentry Reentrant tachyarrhythmia Atrial flutter Atrial fibrillation Ventricular tachycardia Ventricular fibrillation Conduction B/ocks ... 

Enca.inide, Encainide hydrochloride, a ben2amide derivative, is effective in the treatment of ventricular arrhythmias and refractory ventricular tachycardia (1,2). 

Indeca.inide. Indecainide hydrochloride is a po active antiarrhythmic agent that received PDA approval in 1989, but it has not been marketed as of this writing. Chemically, it is 9-[3-(isopropylamino)propyl]fiuorine-9-carboxamide [74517-78-5]. The dmg has potent activity against premature ventricular complexes (PVCs) and ventricular tachycardias. Indecainide has no effect on sinus node function, atrial or ventricular effective refractory periods (32,33). 

Other Glass III Antiarrhythmic Agents. Clofihum phosphate is a benzene-butanaminium derivative that has highly specific Class III antiarrhythmic activity. It is orahy active, has a rapid onset of action, and a reasonably long duration of antiarrhythmic activity. In preliminary clinical studies, clofihum has shown efficacy against spontaneous ventricular tachycardias (69). 

Besides the class I-typical proarrhythmic risk class IA antiarrhythmics possess a marked proarrhythmic risk for the induction of torsade depointes arrhythmia (life-threatening polymorphic ventricular tachycardia observed with most action potential prolonging drugs). 

The amide local anaesthetic lidocaine may also be used as an antianhythmic for ventricular tachycardia and exra-systoles after injection into the blood circulation. Drugs with high lipid solubility such as bupivacaine cannot be used for these purposes because their prolonged binding to the channel may induce dysrhythmias or asystolic heart failure [3]. Systemically applied lidocaine has also been used successfully in some cases of neuropathic pain syndromes [4]. Here, electrical activity in the peripheral nervous system is reduced by used-dependent but incomplete sodium channel blockade. 

Torsade de pointes is a life-threatening polymotphic ventricular tachycardia, which occurs in inherited long... 

The cardiotonics are contraindicated in patients with known hypersensitivity, ventricular failure, ventricular tachycardia, or AV block and in the presence of digitalis toxicity. 

Ventricular tachycardia A rapid heartbeat with a rate of more than 100 bpm, usually originating in the ventricles... 

The uses of the antiarrhythmic drug are given in the Summaiy Drug Table Antiarrhythmic Drug3. In general these drugp are used to prevent and treat cardiac arrhythmias, such as premature ventricular contractions (PVCs), ventricular tachycardia (VT), premature atrial contractions (PACs), paroxysmal atrial tachycardia (PAT), atrial fibrillation, and atrial flutter. Some of the antiarrhythmic dru are used for other... 

Proarrhytlimic effects (worsening of the existing arrhythmia or causation of a new arrhythmia) may occur, such as severe ventricular tachycardia or ventricular fibrillation. It is often difficult to distinguish proarrhytlimic effects from the patient s preexisting arrhythmia. 

In humans cardiac arrhythmias have been recorded in 23% of patients when full-face peel was performed in less than 30 min. These arrhythmias included tachycardia, premature ventricular beats, bigeminy, atrial and ventricular tachycardia [19]. 

Cardiovascular Effects. In one case study, a woman who had accidentally consumed about 20 mL of trichloroethylene was reported to have suffered a myocardial infarction within 2 hours of ingestion (Morreale 1976). In two other case studies, men who ingested 350 and 500 mL of trichloroethylene had ventricular arrhythmias that persisted for up to 3 days (Dhuner et al. 1957). The arrhythmias were described as ventricular tachycardia with extrasystoles from different ventricular foci. Cardiac arrhythmia was also reported in a women who drank an unknown amount of trichloroethylene (Perbellini et al. 1991). 

Figure 4.2 Epicardial ECG recorded from an isolated blood-perfused rat heart at the moment of reperfusion. The heart was made regionally ischaemic by occluding a snare around the left anterior descending coronary artery and, after 10 min, reperfused by releasing the snare. Note the rapid onset of ventricular tachycardia (VT) and its subsequent degeneration into ventricular fibrillation (VF). Reproduced with permission from Lawson (1993).

Ventricular Fibrillation/Pulseless Ventricular Tachycardia Algorithm... 

Treat polymorphic ventricular tachycardia (irregular rate and form) as ventricular fibrillation (see Table 1.9)... 

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