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Premature Ventricular Complexes and Intramural Scarring
Quick Takes
- A shallower scar depth was associated with an increased chance of procedural success, independent of the total scar size or septal wall thickness.
- Ablation in the presence of a larger scar often changes the breakout sites of the intramural focus necessitating mapping and ablation of adjacent anatomic areas.
- DE-CMR imaging can suggest the potential need for adjunctive measures to target deep scar (e.g., bipolar or simultaneous unipolar radiofrequency ablation, half-normal saline ablation, needle ablation, coronary venous and arterial ethanol ablation).
Study Questions:
What are the intramural scar characteristics associated with successful premature ventricular complex (PVC) ablations?
Methods:
The investigators performed mapping and ablation of PVCs in a consecutive series of patients with intramural scarring and frequent PVCs. Data from delayed enhanced cardiac magnetic resonance (DE-CMR) were assessed and the proximity of the endocardium containing the breakout site to the intramural scar was correlated with outcomes. Receiver operating characteristic curves were created to compare scar depth with procedural outcomes, and cutoff points were calculated based on the Youden index. Logistic regression was used to assess the impact of scar depth on procedural outcomes.
Results:
Fifty-six patients were included, and intramural ventricular arrhythmias (VAs) were successfully targeted in 42 patients (75%) and ablation failed in 14 patients (25%). Scarring was more superficial to the endocardium in patients with successful ablations compared with patients with failed procedures (0.35 [interquartile range (IQR), 0.22-1.20] mm vs. 2.45 [IQR, 1.60-3.13] mm; p < 0.001). In 18 (32%) patients, ablation at the breakout site resulted in a significant change of the PVC-QRS morphology that could successfully be ablated in 9 of 12 patients from another anatomical aspect of the wall harboring the intramural scar. The scar was larger in size (1.79 [IQR, 1.25-2.85] cm3 vs. 1.00 [IQR, 0.59-1.68] cm3; p < 0.005) compared with patients who did not have a change in the PVC-QRS morphology with ablation.
Conclusions:
The authors concluded that ventricular arrhythmias in patients with intramural scarring can be successfully ablated especially if the intramural scar is within close proximity to the anatomic area containing the breakout site.
Perspective:
This study suggests that a shallower scar depth was associated with an increased chance of procedural success, independent of the total scar size or septal wall thickness. Furthermore, ablation in the presence of a larger scar often changes the breakout sites of the intramural focus necessitating mapping and ablation of adjacent anatomic areas. Of note, DE-CMR can identify the extent and depth of intramural scar and suggest the potential need for adjunctive measures to target deep scar (e.g., bipolar or simultaneous unipolar radiofrequency ablation, half-normal saline ablation, needle ablation, coronary venous and arterial ethanol ablation).
Clinical Topics: Arrhythmias and Clinical EP, Noninvasive Imaging, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Magnetic Resonance Imaging
Keywords: Arrhythmias, Cardiac, Cardiac Electrophysiology, Catheter Ablation, Diagnostic Imaging, Endocardium, Magnetic Resonance Imaging, Tachycardia, Ventricular, Ventricular Premature Complexes
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