[Optimized programming of sustained rate duration in patients with implantable cardioverter-defibrillators and...

The discrimination of supraventricular versus ventricular tachycardias by an implantable cardioverter-defibrillator (ICD) is still a remaining clinical problem. The false positive detection of supraventricular as ventricular tachycardias causes inadequate electrical therapies of the ICD. To improve the increase of specificity criterias like "Onset" or "Stability" are offered. If these criterias during tachycardia are not fulfilled, the "sustained rate duration" (SRD) is offered as a security criterion. The SRD reasons the delivery of the therapy during tachycardia after a programmable time. Aim of the study was to evaluate, if SRD in patients with known arrhythmia absoluta (AA) in atrial fibrillation and programmed "Onset"/"Stability" increases the sensitivity without loss of specificity in the treatment of hemodynamically tolerated ventricular tachycardias and which programming should be chosen. Our patient collective included 274 patients (pts) with new implanted ICD of the third generation. In 39 (14%) pts AA was known in the medical history. From these 39 (100%) pts, 18 (46%) pts had known tachyarrhythmic episodes (group I) in the area of the ventricular tachycardia-zone > or = 160 beats per minute, whereas in 21 (54%) pts a tachyarrhythmia absoluta (TAA) was unknown (group II). During follow-up of 12 +/- 8 (2-26) months, 151 tachycardias occurred and could be classified as supraventricular tachycardias by stored electrograms. In 9/18 pts of group I, a TAA occurred during follow-up. The initial programmed SRD during first TAA was 62 +/- 39 (35-90) s and was prolonged to 135 +/- 64 (90-180) s. After this prolongation, no inadequate therapy was delivered. In group II, 19/21 (90%) were inadequately treated during TAA. The initial SRD-programming was 45 +/- 28 (0-90) s and was prolonged to 201 +/- 150 (60-480) s during follow-up. After prolongation of the SRD, no more inadequate therapies due to AA were delivered. In pts with new implanted ICD and known TAA, which is hemodynamically tolerated, the SRD should be programmed beside all other available detection parameters for improving the increase of specificity at least 135 s to avoid inadequate therapies of the ICD. In pts with unknown TAA, SRD should be prolonged to 135 s at least the second tachyarrhythmic episode, which is hemodynamically well tolerated.