Abstract DGKherbst2002

P249	One chamber ICD patients: Classification of tachycardias by the new Wavelet algorithm.
¹L.G.C.Luethje, ¹D.Vollmann, ²G.Goertler, ¹Chr.Unterberg
¹Georg-August-Universität, Göttingen; ²Medtronic Inc., Düsseldorf.

Purpose: Wavelet is a new algorithm for the classification of tachycardias implemented in the Medtronic Marquis VR. This template matching algorithm automatically compares the EGM morphology in the ventricular tachycardia/fibrillation (VT/VF)-zones to a stored template during baseline rhythm. If the matching percentage of at least 3 of 8 beats is (nominal) above 70%, the rhythm is classified as supraventricular, otherwise it is classified as VT/VF. So far it is not known which EGM source is best for correct classification. Two EGM sources Can to SVC (HVA/HVX) and Can to RV (HVA/HVB) were compared for the adequate classification of tachycardias by the Wavelet criterion.

Methods: 20 patients with a dual coil lead implanted were randomly programmed to EGM Can to SVC or Can to RV for the Wavelet algorithm. To accelerate the underlying supraventricular rhythm an exercise test was performed and the VT-zone was programmed to 100/min (therapies off). The matching percentage between the template and the EGM morphology during the test were evaluated at different frequencies. In the second run the same test was repeated with the other EGM source programmed.

Results: 4873 matching percentages were analyzed. The similarity of EGM morphology to the template was significantly higher (p<0,05) with the Can to RV source (mean±SD: 89,6%±5,47) than with the Can to SVC source (mean±SD: 72,42±13,84). However, in one patient Can to SVC showed significantly higher similarities (p<0,001). Altogether 21 episodes in the VT-zone were stored by the ICD. 7 episodes with Can to SVC and 8 episodes with Can to RV as EGM source were adequately classified as SVT. Inadequate classification was apparent in 5 episodes with Can to SVC and 1 episode with Can to RV.

Conclusion: For the majority of patients Can to RV is the EGM source of choice for the new Wavelet algorithm and should be programmed routinely. Nevertheless in a small percentage of patients Can to SVC may be superior.