title: Differentiation between monomorphic ventricular tachycardia and sinus tachycardia based on the right ventricular evoked potential.
abstract: The differentiation between ventricular tachycardia (VT) and sinus tachycardia (ST) is problematic in some patients with implantable defibrillators and/or antitachycardia pacemakers. The integral of the ventricular endocardial evoked response, or paced depolarization integral (PDI), has been demonstrated to undergo characteristic changes with a variety of stimuli including catecholamines, pacing rate, and exercise. We hypothesized that the PDI recorded from a unipolar transvenous right ventricular endocardial catheter would differentiate VT from ST. The PDI was calculated from a unipolar pacing stimulus, delivered via a cathode in the right ventricular apex, and the reference electrode, a quadripolar catheter positioned in the superior vena cava. PDIs were measured in 22 patients during VT and sinus rhythm. The PDI measured during sinus rhythm was 579 +/- 240 microV-sec and the PDI during VT was 894 +/- 411 microV-sec (P < 0.001). In a subset of seven patients, PDIs were measured during VT, sinus rhythm, and ST induced by catecholamine infusion or exercise. In this subset, the PDI during sinus rhythm was 645 +/- 295 microV-sec, during ST 588 +/- 308 microV-sec (9% decrease from sinus, P = 0.05), and during VT 863 +/- 342 microV-sec (33.9% increase, P = 0.01). These data indicate that the measurement of the PDI is potentially useful in differentiating VT from ST.
mesh_terms: D000465:Algorithms; D006328:Cardiac Catheterization; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003937:Diagnosis, Differential; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D013616:Tachycardia, Sinus / Q000175:diagnosis* / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology; D016278:Ventricular Function, Right / Q000502:physiology*