Successful Identification of and Discrimination Between Atrial and Ventricular Arrhythmia with the Aid of Pacing and Defibrillator Devices

Abstract

The presence of supraventricular tachycardia is the leading cause of inappropriate shock in ICD recipients, and it can be a significant cause of morbidity, psychological distress and worsened clinical outcome. Modern pacing and ICD systems offer a number of discriminators that are integrated into algorithms to differentiate sustained ventricular tachycardia from supraventricular tachycardia. These algorithms can be adapted and optimised for each individual patient to ensure that only those arrhythmias that need treatment through the use of an ICD, are actually treated. This review summarises the single- and dual-chamber discriminators that can be used in the detection and classification of tachyarrhythmias.

Catastrophic implantable cardioverter-defibrillator misclassification of ventricular tachycardia

“…An automated feature for collecting templates periodically verifies the template's quality and updates it when modifications to the intrinsic EGM are detected [6] . Some manufacturers establish their own algorithms for VT/SVT discrimination using different sequences of discriminators, as shown in Table 1 [2] . In this case, the patient implemented a single-chamber discriminator ICD device whose data collection set-up applies the far-field vector (can to right ventricular -RV -tip) and near-field vector (RV tip to RV ring) for alignment and correlation of the far-field QRS complex with the template.…”

“…There are several possible causes why the Wavelet morphology criterion device can result in an inaccurate ICD classification. These include errors in aligning the electrograms, truncation of the electrograms (signal clipping caused by incorrect amplifier settings), distortions in the electrograms due to myopotentials, changes in the morphology of the lead over time or bundle-branch block, and distortion in the electrograms immediately after shock delivery [2,10] . A non-randomised study by Toquero et number is reduced by about 42% when the programmed threshold is 75% instead of 70% (the nominal value).…”

“…Intracardial devices (ICDs) are crucial therapy for ventricular tachyarrhythmias (VT or ventricular fibrillation, VF) and to reduce the risk of sudden cardiac death [ 1 ] . Inappropriate shock transmission or undelivered shock have been linked to a considerable increase in morbidity and even worse, fatal outcomes in patients with ICDs [ 2 ] . The most common cause of inappropriate ICD therapy is inaccurate interpretation by the device of sinus tachycardia or atrial fibrillation/flutter with rapid atrioventricular conduction.…”