Discrimination of ventricular tachycardia from supraventricular tachycardia in implantable cardioverter defibrillators by automated electrogram morphology analysis: can leads finally replace the electrophysiologist?

Inappropriate device discharges for misclassified supraventricular tachycardia (SVT) may be considered as unavoidable burden within the safety philosophy of implantable cardioverter defibrillator (ICD) therapy. At least, this seems to be the painful lesson that patients and their caring doctors had to learn during the past decade with ever increasing rates of device implantation for secondary and primary prevention. During this recent period, almost all studies that at first hand showed significant survival benefits by the ICD also reported rates of up to 52% of all shock therapies in 10–22% of patients to be inappropriately delivered for SVT, as retrospectively assessed from the stored electrograms.1–3For a long time, only standard programming features, such as ‘rate stability’ and ‘sudden onset’, were available to address this clinical problem. In the late 1990s, dual-chamber ICDs received market approval, and the integrated information from an atrial lead for SVT detection significantly improved the suppression of inappropriate electrotherapy.4 In clinical practice, this was specifically relevant in patients with recurrent slow ventricular tachycardias (VTs) with the need of programming very long detection intervals resulting in a more than three-fold increase of the SVT burden.5 However, overall benefits of dual-chamber vs. single-chamber ICD implantation remain a matter of controversial debate.Moreover, the dominant arrhythmia inappropriately treated with shocks is fast-conducted … *Corresponding author. Tel: +49 40 1818824811; fax: +49 40 1818824819. E-mail address : g.groenefeld{at}asklepios.com