Sinus Rhythm

Pirmenol. Pirmenol hydrochloride, a pyridine methanol derivative, is a racemic mixture. It has Class lA antiarrhythmic activity, ie, depression of fast inward sodium current, phase 0 slowing, and action potential prolongation. The prolongation of refractory period may be a Class III property. This compound has shown efficacy in converting atrial arrhythmias to normal sinus rhythm (34,35). 

Propranolol. Propranolol hydrochloride, considered the prototype of the P-adrenoceptor blocking agents, has been in use since 1964. It is a nonselective, highly Hpid-soluble P-adrenoceptor blocker having no ISA. It is a mixture of (+) and (—) enantiomers, and the (—) enantiomer is the active moiety. The local anesthetic effects of propranolol are equipotent to those of Hdocaine [137-58-6] C 4H22N20, (see Anesthetics). Therapeutic effects include termination of catecholamine-induced arrhythmias, conversion of SA nodal tachycardias (including flutter and fibrillation) and AV nodal tachyarrhythmias to normal sinus rhythm, digitahs-induced arrhythmias, and ventricular arrhythmias (1,2). The dmg also has cardioprotective properties (37,39). 

The sinus rhythm is the heart rhythm in which the sinus node generates an electrical impulse that travels through specialized cells (that form a conduction system) and leads to a ventricular contraction. 

Singh S, Singh B, Reda D, et al. [Abdellatif M]. Comparison of sotalol vs. amio-darone in maintaining stability of sinus rhythm in subjects with atrial Fibrillation (Sotalol-Amiodarone Atrial Fibrillation Effectiveness Trial [SAFE-T]). Am J Cardiol 2003 92 468-72. 

Normal sinus rhythm and a left atrial diameter >5.5 cm... 

A CarboMetrics bileaflet valve or Medtronic Hall tilting disk mechanical valve in the aortic position, with normal left atrial size and normal sinus rhythm... 

ECG normal sinus rhythm, PR 0.16 s, QRS 0.08 s, QTC 0.38 s, occasional polymorphic premature ventricular contractions, 3 mm ST-segment elevation anterior leads... 

Compare and contrast the mechanisms of action of drugs used for ventricular rate control, conversion to sinus rhythm and maintenance of sinus rhythm in patients with AF, and explain the importance of anticoagulation for patients with AF. 

Antiarrhythmic drug therapy for maintenance of sinus rhythm/reduction in frequency of episodes of AF should be initiated only in patients in whom symptoms persist despite maximal doses of drugs for ventricular rate control. 

The desired outcomes for treatment are to restore normal sinus rhythm and alleviate patient symptoms. 

Monitor the patient for termination of AV nodal blockade and restoration of normal sinus rhythm, heart rate, and alleviation of symptoms. 

Direct current cardioversion is the process of administering a synchronized electrical shock to the chest. The purpose of DCC is to simultaneously depolarize all of the myocardial cells, resulting in interruption and termination of the multiple reentrant circuits and restoration of normal sinus rhythm. The initial energy level of the shock is 100 joules (J) if the DCC attempt is unsuccessful, successive cardioversion attempts maybe made at 200,300, and 360 J.14 Delivery of the shock is synchronized to the ECG by the cardioverter machine, such that the electrical charge is not delivered during... 

Conversion to Sinus Rhythm Termination of AF in hemodynami-cally stable patients may be performed using antiarrhythmic drug therapy or elective DCC. Drugs that may be used for conversion to sinus rhythm are presented in Table 6-7 these agents... 

Conversion of AF to sinus rhythm is usually performed in patients with the first detected episode of AF or in patients with an episode of persistent AF. In patients with permanent AF, conversion to sinus rhythm is usually not attempted because cardioversion is unlikely to be successful, and in those... 

Maintenance of Sinus Rhythm/Reduction in the Frequency of Episodes of Paroxysmal AF In many patients, permanent maintenance of sinus rhythm following cardioversion is an unrealistic goal. Many, if not most, patients experience recurrence of AF after cardioversion. Therefore, a more realistic goal for many... 

In recent years, numerous studies have been performed to determine whether drug therapy for maintenance of sinus rhythm is preferred to drug therapy for ventricular rate control.28-31 In these studies, patients have been assigned randomly to receive therapy either with drugs for rate control or with drugs for rhythm control (Table 6-8). These studies have found... 

TABLE 6-7. Drugs for Conversion of Atrial Fibrillation to Normal Sinus Rhythm... 

FIGURE 6-7. Decision algorithm for conversion of atrial fibrillation to normal sinus rhythm. 

TABLE 6-8. Drugs for Maintenance of Sinus Rhythm/ Reduction in the Frequency of Episodes of Atrial Fibrillation... 

Monitor ECG to assess continued presence of AF and to determine whether conversion to sinus rhythm has occurred. 

The desired outcomes for treatment are to terminate the arrhythmia, restore sinus rhythm, and prevent recurrence. Drug therapy is employed to terminate the arrhythmia and restore sinus rhythm nonpharmacologic measures are employed to prevent recurrence. 

Monitor patients for termination of PSVT and restoration of normal sinus rhythm. 

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