Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM)
Condition: Arrhythmia; Cardiovascular Diseases; Death, Sudden, Cardiac; Heart Diseases; Tachycardia, Ventricular; Ventricular Arrhythmia; Ventricular Fibrillation
MeSH terms: Cardiovascular Diseases; Heart Diseases; Arrhythmias, Cardiac; Tachycardia; Ventricular Fibrillation; Tachycardia, Ventricular; Death, Sudden, Cardiac; Death, Sudden
Study type: Interventional
Phase: Phase 3

Summary: 
      To determine whether electrophysiologic study (EPS) or Holter monitoring (HM) was the better
      method for selecting effective long-term antiarrhythmic drug therapy in patients with
      sustained ventricular tachycardia, ventricular fibrillation, or an episode of aborted sudden
      death.
    

Detailed description: 
      BACKGROUND:

      There had been no prospective, randomized studies that compared the accuracy of EPS versus HM
      in guiding long-term drug therapy for ventricular tachycardia or ventricular fibrillation.
      Success had been reported using both techniques. Using a rigorous ECG monitoring protocol in
      patients, a less than five percent per year incidence of sudden death had been reported.
      Several investigators reported that the results of electropharmacologic testing were
      predictive of clinical response. One of the largest studies, by Mason and Winkle, reported
      that, in 51 patients with recurrent ventricular tachycardia who were treated with drugs
      predicted to be effective based on the results of electropharmacologic testing, ventricular
      tachycardia did not recur in 68 percent at 18 months of follow-up. In contrast, ventricular
      tachycardia did not recur in only 11 percent of patients treated with drugs predicted to be
      ineffective.

      Two prior studies had compared, in a non-randomized fashion, the predictive accuracy of EPS
      and HM in treating patients with ventricular tachycardia/ ventricular fibrillation. A
      retrospective analysis of 44 patients with ventricular tachycardia/ventricular fibrillation
      who underwent both HM and EPS was performed in which the elimination of ventricular
      tachycardia on the HM and the suppression of ventricular tachycardia induced during
      programmed stimulation was the therapeutic goal. The positive and negative predictive value
      of EPS was found to be 88 percent and 94 percent, respectively. The corresponding values for
      ECG monitoring were found to be 70 percent and 50 percent, respectively. It was concluded
      that EPS provided a higher degree of accuracy than HM in predicting the long-term clinical
      response to drug therapy, over a mean follow-up of 18 months. However, in this study the
      criterion for judging efficacy by HM was a liberal one and involved only the elimination of
      ventricular tachycardia.

      A second study examined the results of HM in 19 patients with ventricular tachycardia who
      were treated based on EPS. Among eight patients, in whom inducible ventricular tachycardia
      was suppressed during electrophysiologic testing, six had no change or worsening of premature
      ventricular contractions on the HM. These patients had a benign follow-up despite the
      continued presence of frequent or complex ventricular ectopy. It was concluded that EPS was
      superior to HM in predicting successful drug therapy.

      Existing data suggested that both electrophysiologic testing and Holter monitoring might be
      effective techniques for determining effective drug therapy for ventricular
      tachycardia/ventricular fibrillation. However, there was not enough data available to assess
      which technique was more effective. A prospective, randomized comparison of the two
      techniques would be a very significant contribution which could potentially have a major
      impact on the medical community.

      DESIGN NARRATIVE:

      Randomized, fixed sample, multicenter trial conducted at 14 institutions. Patients meeting
      clinical criteria underwent Holter monitoring. Those having an average of 30 premature
      ventricular contractions per hour underwent EPS. Those having inducible ventricular
      tachycardia were randomized into an EPS arm or to a Holter exercise treadmill arm of drug
      testing. Each patient received, in random sequences, up to six antiarrhythmic drugs. When an
      effective drug was found, patients underwent a predischarge HM and exercise test. Follow-up
      continued for one year after the last subject had been randomized. The primary endpoint in
      the trial was time to arrhythmia recurrence during therapy with a drug predicted to be
      effective by either EPS or HM.
    

Intervention name(s): electrophysiology; electrocardiography, ambulatory; imipramine; mexiletine; procainamide; quinidine; sotalol
Intervention type(s): Procedure; Procedure; Drug; Drug; Drug; Drug; Drug
Intervention MeSH terms: Quinidine; Sotalol; Mexiletine; Procainamide; Imipramine
Allocation: Randomized
Primary purpose: Treatment