Feasibility of Two-Dimensional Speckle-Tracking Echocardiography for Assessing Ablation Complexity in Left Ventricular Outflow Tract Premature Ventricular Contractions
Shinya Yamada, Takashi Kaneshiro, Minoru Nodera, Sadahiro Murota, Hidetomo Onuma, Yukio Yamadera, Masayoshi Oikawa, Takafumi Ishida, Yasuchika TakeishiBACKGROUND:
The origins of left ventricular outflow tract premature ventricular contractions (PVCs) differ in depth and may involve preferential pathways, potentially requiring complex ablation. However, a noninvasive method to preprocedurally estimate ablation complexity has not been established.
METHODS:
Sixteen patients with idiopathic left ventricular outflow tract PVCs (V2 transition ratio ≥0.6) underwent 2-dimensional speckle-tracking echocardiography during monomorphic PVCs. Endocardial peak systolic strain timing in 18 left ventricular segments was displayed on a bull’s-eye map using 8 color-coded intervals (0–800 ms). Patients were classified as localized (n=6) when the earliest interval appeared in 1 segment and nonlocalized (n=10) when it involved ≥2 segments. Ablation outcomes were compared according to whether a simple ablation approach (PVC elimination within 30 s at a single site) was achieved.
RESULTS:
Baseline electrocardiographic characteristics were comparable between the groups. Ablation-related parameters, including contact force, power output, and impedance drop at the initial ablation site, were also similar. However, the nonlocalized group required statistically significantly greater total radiofrequency energy to eliminate the targeted PVCs (median, 22 206 versus 10 409 J;
CONCLUSIONS:
A localized earliest-strain pattern was associated with successful PVC elimination using a simple ablation approach, whereas a nonlocalized pattern indicated the need for more complex ablation. This simple, noninvasive metric may aid preprocedural planning for left ventricular outflow tract PVC ablation.