Introduction: Premature ventricular contractions (PVCs) frequently originate from the outflow tract of the right ventricle (RVOT) or left ventricle (LVOT). Catheter-based mapping and ablation of RVOT PVCs employs simple venous access, while LVOT PVCs often require arterial access and more extensive mapping of the aorta, coronary cusps, and coronary venous system. Pre-procedural determination of PVC origin could direct an operator to the appropriate anatomical site and significantly improve procedure times, success rates, and patient safety. Detailed analyses of leads V1 and V2 on a 12-lead ECG are helpful in this regard, but results are strongly dependent on accurate placement of those leads. A particular type of QRS morphology, composed of a broad base and early slurring with terminal sharp activation, has been observed on ambulatory Holter monitors. We have designated this pattern the “Teton Sign” (ARROWS ON ACCOMPANYING IMAGE). It is observed independent of specific lead location.
Hypothesis: The characteristic Teton Sign QRS pattern is due to fusion of epicardial (early) and endocardial (late) activation of the LV ostium, and is therefore present for LVOT PVCs but not RVOT PVCs.
Methods: 40 consecutive patients undergoing catheter ablation for outflow tract PVCs were included. Retrospective review of pre-procedure 3-lead Holter monitors (for presence of Teton Sign) and procedure reports (for successful ablation site) was performed.
Results: Mean PVC burden was 27,879/24 hours. Teton Sign was observed in 18 patients (45%). Site of successful ablation included 17 RVOT and 23 LVOT (1 RCC, 7 LCC, 7 RCC/LCC commissure, 5 intramural, 3 LV summit). Teton Sign was present on Holters for 0/17 RVOT and 18/23 LVOT patients. Teton Sign demonstrated 78% sensitivity, 100% specificity, 77% NPV, 100% PPV for LVOT PVCs.
Conclusion: Presence of a Teton Sign on a standard 3-lead ambulatory Holter monitor strongly predicts LVOT site of origin, independent of specific lead location.