Ventricular rhythm, determining

You can use eHher of the following methods to determine atrial or ventricular rhythm. 

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... 

Disturbances of cardiac rhythm (e.g., tachycardia, atrial fibrillation, ventricular flutter, and A-V or intraventricular block) are the most frequent causes of death. Thus, management of cardiac function is critical. If the patient survives the early phase, recovery without sequelae is probable, and vigorous resuscitative measures are important. A major clinical problem is determining when a patient is no longer in danger. Many patients with mild overdose have been hospitalized... 

Electrocardiography is useful for determining rhythm disturbances (tachy-or bradyarrhythmias) and changes in ventricular and atrial size. 

Arterial pulses are an accurate measure of the ventricular rate in healthy persons with good ventricular function. In patients with a rapid ventricular rate—because of supraventricular tachyarrhythmias such as atrial flutter or fibrillation or rapid ventricular rates (e.g., ventricular tachycardia or premature ventricular beats)—extremity pulses (e.g., radial pulse) may be considerably slower than the true ventricular rate. A more accurate ventricular rate is determined by listening to the ventricles with the stethoscope (usually at the apex) or counting from an ECG. In patients with atrial fibrillation and a fast ventricular rate, a pulse deficit (measure of the difference in true ventricular rate and peripheral pulse rate) may exist. This may be as much as 10 to 20 beats per minute. Thus the location of the pulse (radial or apical) should be recorded. The pulse deficit will be reduced as the ventricular rate is controlled with drug therapy or normal sinus rhythm is restored. 

While the true impact of rhythm control on mortality remains to be determined, current data suggest that the restoration and maintenance of sinus rhythm in patients with AF may impart other important clinical benefits, such as improvements in symptoms, exercise tolerance, ability to perform activities of daily living and quality of life (41). In the Rate Control versus Electrical Cardioversion (RACE) study, patients with AF who converted to sinus rhythm had a significant reduction in atrial size and improvement in left ventricular function (36). Despite efforts to enroll patients who would tolerate rate-controlled AF, the AFFIRM Functional Status Substudy showed that AF was associated with poorer New York Heart Association (NYHA) functional capacity and rhythm control was associated with a modest improvement in six-minute walk distance compared to rate control (42). 

Lidocaine is the drug of choice for ventricular dysrhythmias, but the client must be monitored by telemetry to determine the specific rhythm. 

The effects of therapy should be evaluated once it is determined that the electrograms and symptoms are consistent with a ventricular tachyarrhythmia. Evaluation of electrograms also provides clues on the effects of therapy. After therapy was given did the patient have return to sinus rhythm or was persistent arrhythmia present For episodes treated with shocks, the impedance measured during the event should be compared to impedances obtained during shocks at implant. Impedances normally range from 30-80 Q, depending on lead type... 

The tachycardia is clearly VT, and terminates spontaneously as the device begins to charge. After completion of charging, this model ICD (Guidant Prizm) makes a determination of the need to divert the shock due to a non-sustained rhythm. In order for a divert to occur in this ICD model, however, slow" (below rate cutoff) ventricular events need to be sensed. Paced beats are not counted as slow in this device. Because there were no sensed ventricular events, due to the patient s complete heart block, the ICD assumes the rhythm to be VF too fine to be sensed and delivers a shock. 

Differentiating ventricular tachycardia (VT) from supraventricular tachycardia (SVT) with aberrancy is difficult. Careful assessment of a 12-lead ECC or rhythm strip can help you determine the arrhythmia with 90% accuracy. 

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