References:
  1. Kredieh B, Rodriguez-Manero M, Schurmann P, Ibarra-Cortez SH, Dave AS, Valderrabano M. Retrograde coronary venous ethanol infusion for ablation of refractory ventricular tachycardia. Circ Arrhythm Electrophysiol. 2016, 9; e004352
  2. Anderson RH, Mohun TJ, Sanchez-Quintana D, Mori S, Spicer DE, Cheung JW, Lerman BB. The anatomic substrates for outflow tract arrhythmias. Heart Rhythm 2019; 16: 290-297
  3. Hachiya H, Yamauchi Y, Iesaka Y, Yagishita A, et al. Discrete pre-potential as an indicator of successful ablation in patients with coronary cusp ventricular arrhythmia. Circ Arrhythm Electrophysiol 2013; 6: 898-904
  4. Liao H, Mei W, Tanager KS, Miele F, et al. Left ventricular summit arrhythmias with an abrupt V3 transition: Anatomy of the aortic interleaflet triangle vantage point. Heart Rhythm 2021; 18: 10-19
  5. Anderson RD, Kumar S, Parmeswaran R, et al. Differentiating right- and left-sided outflow tract ventricular arrhythmias: Classical ECG signatures and prediction algorithms. Circ Arrhythm Electrophysiol 2019; 12: e007392
  6. Bradfield JS, Homsi M, Shivkumar K, Miller JM. Coupling interval variability differentiates ventricular ectopic complexes arising in the aortic sinus of Valsalva and great cardiac vein from other sources.
  7. Waight MC, Li AC, Leung LW, et al. Hourly variability in outflow tract ectopy as a predictor of its site of origin. Present issue of this journal
  8. Hsia BC, Greige N, Patel SK, et al. Determining the optimal duration for premature ventricular contraction monitoring. Heart Rhythm 2020; 17: 2119-2125
  9. Janse MJ, Coronel R, G Wilms-Schopman FJ, de Groot J. Mechanical effects on arrhythmogenesis: from pipette to patient. Progress in Biophys Mol Biol 2003; 82: 187-195
Figure legends:
Figure 1: Delayed activation recorded in left coronary sinus during PVC. The electrograms marked by the blue arrows represent delayed activation of local muscle bundle during sinus rhythm. The delay is likely due to insulation by surrounding fibrous tissue of the ventriculo-aortic junction. The more rounded early electrogram that correspond in timing to the QRS is the electrogram generated by activation of larger muscle of the LV summit. During PVC (second complex in the trace), this electrogram represents earliest activation (black arrow, 40ms pre-systolic) suggesting site of origin of the PVC. PVC = premature ventricular contraction.
Figure 2: Electroanatomic map in the left anterior oblique view with caudal tilt of the ventricular outflow region showing the RV outflow, aortic leaflets and coronary sinus. Earliest activation (red, early; purple, late) is registered in the distal great cardiac vein overlying the LV summit. Ablation suppressed PVCs in the infra-aortic region (blue solid circle) below the commissure of the right and left aortic valve leaflets where electrograms were indistinct. RCC = Right coronary cusp; LCC = left coronary cusp; NCC = non coronary cusp.