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Functional Substrate Mapping of Ventricular Tachycardia
Quick Takes
- Mapping late potentials (LPs) with right ventricular sensed protocol (SP) single extra pacing results in a larger area of LPs identified for ablation than during sinus rhythm (SR) mapping.
- Right ventricular SP single extra pacing has a sensitivity of 87% and a specificity of 96% for identification of LPs, compared with 78% and 65%, respectively, when done in SR.
Study Questions:
What is the role of dynamic substrate changes in facilitating conduction delay and re-entry in ventricular tachycardia (VT) circuits?
Methods:
Thirty patients (mean age 67 years; 27 male subjects) underwent ablation. Mapping was performed with the Advisor HD Grid multipolar catheter. A bipolar voltage map was obtained during sinus rhythm (SR) and right ventricular sensed protocol (SP) single extra pacing. SR and SP maps of late potentials (LPs) and local abnormal ventricular activity (LAVA) were made and compared with critical sites for ablation, defined as sites of best entrainment or pace mapping. Ablation was then performed to critical sites, and LP/LAVA identified by the SP.
Results:
At a median follow-up of 12 months, 90% of patients were free from antitachycardia pacing or implantable cardioverter-defibrillator shocks. SP pacing resulted in a larger area of LP identified for ablation (19 mm2 vs. 6 mm2) during SR mapping (p = 0.001), with a sensitivity of 87% and a specificity of 96%, compared with 78% and 65%, respectively, in SR.
Conclusions:
The authors concluded that LP and LAVA observed during the SP were able to identify regions critical for ablation in VT with a greater accuracy than SR mapping.
Perspective:
The identification of critical areas for radiofrequency ablation of VT includes the characterization of the underlying substrate guided by mapping LPs and local abnormal ventricular activity in SR. The authors of the study show that mapping during right ventricular SP single extra pacing produces a broader area showing both LPs and LAVA, and accounts for dynamic substrate changes facilitating functional block. The authors showed excellent outcome at 12 months. The hypothesis that ventricular SP single extra pacing more accurately identifies critical areas of the substrate must be tested in a randomized prospective trial.
Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure
Keywords: Arrhythmias, Cardiac, Arrhythmia, Sinus, Cardiac Pacing, Artificial, Catheter Ablation, Defibrillators, Implantable, Heart Failure, Myocardial Ischemia, Tachycardia, Ventricular
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