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ICD discrimination of SVT versus VT with 1:1 V-A conduction: A review of the literature.

Cardoso RN, Healy C, Viles-Gonzalez J, Coffey JO - Indian Pacing Electrophysiol J (2016)

Bottom Line: They also impair patients' quality of life, increase hospitalizations, and raise health-care costs.V-A time, electrogram morphology, and response to antitachycardia pacing suggested atrioventricular nodal reentry tachycardia, which was confirmed in an electrophysiology study.Inspired by this case, we performed a literature review to discuss mechanisms for discrimination of supraventricular tachycardia with 1:1 A:V relationship from ventricular tachycardia with 1:1 retrograde conduction.

View Article: PubMed Central - PubMed

Affiliation: Cardiovascular Division, Department of Medicine, University of Miami, Miller School of Medicine, Miami, USA.

ABSTRACT
Inappropriate ICD shocks are associated with increased mortality. They also impair patients' quality of life, increase hospitalizations, and raise health-care costs. Nearly 80% of inappropriate ICD shocks are caused by supraventricular tachycardia. Here we report the case of a patient who received a single-lead dual-chamber sensing ICD for primary prevention of sudden cardiac death and experienced inappropriate ICD shocks. V-A time, electrogram morphology, and response to antitachycardia pacing suggested atrioventricular nodal reentry tachycardia, which was confirmed in an electrophysiology study. Inspired by this case, we performed a literature review to discuss mechanisms for discrimination of supraventricular tachycardia with 1:1 A:V relationship from ventricular tachycardia with 1:1 retrograde conduction.

No MeSH data available.


Related in: MedlinePlus

SMART algorithm for tachycardia analysis used in the Biotronik DX single-lead ICD. In our patient, atrial activity occurred during the post-ventricular atrial blanking period. Thus, the device identified VR > AR (Line 1), and (mistakenly) called the rhythm VT. In case the device had correctly identified VR = AR, the bold sequence illustrates how the rhythm still would have been called VT. Notice this sequence is unable to discriminate AVNRT from VT with retrograde 1:1 conduction (see text for full explanation). Modified from: Lori et al. Implantable cardioverter defibrillator system with floating atrial sensing dipole: A single-center experience. Pacing Clinc Electrophysiol. 2014;37:1265–1273. AR = atrial rate; A/V ≠ N:1 = conduction ratio not integral; SVT = supraventricular tachycardia; VR = ventricular rate; VT = ventricular tachycardia.
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fig5: SMART algorithm for tachycardia analysis used in the Biotronik DX single-lead ICD. In our patient, atrial activity occurred during the post-ventricular atrial blanking period. Thus, the device identified VR > AR (Line 1), and (mistakenly) called the rhythm VT. In case the device had correctly identified VR = AR, the bold sequence illustrates how the rhythm still would have been called VT. Notice this sequence is unable to discriminate AVNRT from VT with retrograde 1:1 conduction (see text for full explanation). Modified from: Lori et al. Implantable cardioverter defibrillator system with floating atrial sensing dipole: A single-center experience. Pacing Clinc Electrophysiol. 2014;37:1265–1273. AR = atrial rate; A/V ≠ N:1 = conduction ratio not integral; SVT = supraventricular tachycardia; VR = ventricular rate; VT = ventricular tachycardia.

Mentions: Different manufacturers use the various discriminators in distinct sequences to establish an algorithm for VT/SVT discrimination. The DX Biotronik ICD system utilizes the SMART algorithm (Fig. 5), which includes heart rate, interval stability, A:V association, and P:R pattern analysis. Atrial and ventricular rates are analyzed first. If the ventricular rate is faster (Fig. 5, line 1), the rhythm is classified as VT. If the atrial rate is faster (Fig. 5, line 2), the rhythm is identified as SVT if either the RR is unstable (suggests variable AV conduction) or the A/V relationship shows an integral conduction ratio (e.g., 2:1, 3:1). If the ventricular and atrial rates are equal (Fig. 5, line 3), the system checks for stability and association. If the RR is stable but the PP is not, there is AV dissociation and VT is identified. If both RR and PP are stable, the rhythm is classified as VT if either the PR changes (AV dissociation) or if there is suddenness of onset. If the RR is unstable, a stable PR (AV association) indicates SVT, whereas an unstable PR (AV dissociation) indicates VT [44]. As shown in the bold sequence of Fig. 5, this algorithm cannot reliably differentiate AVNRT from VT with retrograde 1:1 conduction, given that both arrhythmias present with equal atrial and ventricular rates, stable RR and PP intervals (stability), no PR change (AV association), and sudden onset. In this particular sequence, the SMART system identifies VT. Therefore, the electrophysiologist should have increased awareness of the possibility of AVNRT and apply the concepts discussed here to successfully discriminate this potentially curable arrhythmia.


ICD discrimination of SVT versus VT with 1:1 V-A conduction: A review of the literature.

Cardoso RN, Healy C, Viles-Gonzalez J, Coffey JO - Indian Pacing Electrophysiol J (2016)

SMART algorithm for tachycardia analysis used in the Biotronik DX single-lead ICD. In our patient, atrial activity occurred during the post-ventricular atrial blanking period. Thus, the device identified VR > AR (Line 1), and (mistakenly) called the rhythm VT. In case the device had correctly identified VR = AR, the bold sequence illustrates how the rhythm still would have been called VT. Notice this sequence is unable to discriminate AVNRT from VT with retrograde 1:1 conduction (see text for full explanation). Modified from: Lori et al. Implantable cardioverter defibrillator system with floating atrial sensing dipole: A single-center experience. Pacing Clinc Electrophysiol. 2014;37:1265–1273. AR = atrial rate; A/V ≠ N:1 = conduction ratio not integral; SVT = supraventricular tachycardia; VR = ventricular rate; VT = ventricular tachycardia.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834441&req=5

fig5: SMART algorithm for tachycardia analysis used in the Biotronik DX single-lead ICD. In our patient, atrial activity occurred during the post-ventricular atrial blanking period. Thus, the device identified VR > AR (Line 1), and (mistakenly) called the rhythm VT. In case the device had correctly identified VR = AR, the bold sequence illustrates how the rhythm still would have been called VT. Notice this sequence is unable to discriminate AVNRT from VT with retrograde 1:1 conduction (see text for full explanation). Modified from: Lori et al. Implantable cardioverter defibrillator system with floating atrial sensing dipole: A single-center experience. Pacing Clinc Electrophysiol. 2014;37:1265–1273. AR = atrial rate; A/V ≠ N:1 = conduction ratio not integral; SVT = supraventricular tachycardia; VR = ventricular rate; VT = ventricular tachycardia.
Mentions: Different manufacturers use the various discriminators in distinct sequences to establish an algorithm for VT/SVT discrimination. The DX Biotronik ICD system utilizes the SMART algorithm (Fig. 5), which includes heart rate, interval stability, A:V association, and P:R pattern analysis. Atrial and ventricular rates are analyzed first. If the ventricular rate is faster (Fig. 5, line 1), the rhythm is classified as VT. If the atrial rate is faster (Fig. 5, line 2), the rhythm is identified as SVT if either the RR is unstable (suggests variable AV conduction) or the A/V relationship shows an integral conduction ratio (e.g., 2:1, 3:1). If the ventricular and atrial rates are equal (Fig. 5, line 3), the system checks for stability and association. If the RR is stable but the PP is not, there is AV dissociation and VT is identified. If both RR and PP are stable, the rhythm is classified as VT if either the PR changes (AV dissociation) or if there is suddenness of onset. If the RR is unstable, a stable PR (AV association) indicates SVT, whereas an unstable PR (AV dissociation) indicates VT [44]. As shown in the bold sequence of Fig. 5, this algorithm cannot reliably differentiate AVNRT from VT with retrograde 1:1 conduction, given that both arrhythmias present with equal atrial and ventricular rates, stable RR and PP intervals (stability), no PR change (AV association), and sudden onset. In this particular sequence, the SMART system identifies VT. Therefore, the electrophysiologist should have increased awareness of the possibility of AVNRT and apply the concepts discussed here to successfully discriminate this potentially curable arrhythmia.

Bottom Line: They also impair patients' quality of life, increase hospitalizations, and raise health-care costs.V-A time, electrogram morphology, and response to antitachycardia pacing suggested atrioventricular nodal reentry tachycardia, which was confirmed in an electrophysiology study.Inspired by this case, we performed a literature review to discuss mechanisms for discrimination of supraventricular tachycardia with 1:1 A:V relationship from ventricular tachycardia with 1:1 retrograde conduction.

View Article: PubMed Central - PubMed

Affiliation: Cardiovascular Division, Department of Medicine, University of Miami, Miller School of Medicine, Miami, USA.

ABSTRACT
Inappropriate ICD shocks are associated with increased mortality. They also impair patients' quality of life, increase hospitalizations, and raise health-care costs. Nearly 80% of inappropriate ICD shocks are caused by supraventricular tachycardia. Here we report the case of a patient who received a single-lead dual-chamber sensing ICD for primary prevention of sudden cardiac death and experienced inappropriate ICD shocks. V-A time, electrogram morphology, and response to antitachycardia pacing suggested atrioventricular nodal reentry tachycardia, which was confirmed in an electrophysiology study. Inspired by this case, we performed a literature review to discuss mechanisms for discrimination of supraventricular tachycardia with 1:1 A:V relationship from ventricular tachycardia with 1:1 retrograde conduction.

No MeSH data available.


Related in: MedlinePlus