THE VALUE OF RATE REGULARITY AND MULTIPLICITY MEASURES TO DETECT VENTRICULAR-TACHYCARDIA IN THE PRESENCE OF ATRIAL-FIBRILLATION OR FLUTTER

The predominant cause of inappropriate therapy by implantable antitach ycardia devices with pacing and nonpacing cardioverter ter defibrillat ors, is mistaking a fast ventricular response during atrial fibrillati on or flutter with true ventricular tachycardia (VT). The distinction between these arrhythmias is an important consideration in addressing the problem of reducing false-positives in detection mechanisms for im plantable devices. Dual chamber analysis that examines atrial and vent ricular event ratios has been proposed as a solution to this problem, but would still fail in distinguishing paroxysmal VT requiring treatme nt from a fast but otherwise benign ventricular response during atrial fibrillation or flutter. In this study, two methods for discriminatin g these tachyarrhythmias were evaluated. Method 1 examined ventricular rate and rate regularity as a method for VT detection. Method 2 combi ned rate and regularity as well as an additional multiplicity criterio n for recognition of atrial flutter with a fast ventricular response. In 20 patients, Method 1 had 100% sensitivity of VT detection and 80% specificity for detection of atrial fibrillation or flutter. Method 2 had 90% sensitivity and 90% specificity. These results suggest that us e of these algorithms in future implantable devices would result in a decrease in false-positive device therapies.