LVOT Ventricular Tachycardia

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Contents 1 EKG 2 EKG Characteristics 3 Ablation 4 Criteria for Successful Ablation 5 References

EKG

EKG Characteristics

• All patient have a LBBB, inferior axis, with pointed QRS in the inferior leads and early transition in V2 or V3.
• Patients with LCC commonly have a rS in Lead I and NCC may have a bifid (notched) R wave in Lead I
• QRS voltages on leads II, III, and aVF on the coronary cusp group ECGs are signifcantly greater than those on the endocardial LVOT group ECGs (2.25+/-0.30 mV vs 1.66+/- 0.42 mV).
• The presence of an S wave on both leads V5 and V6 or on V6 alone identifed the endocardial LVOT VT with 100% sensitivity.
• Absence of an S wave on either lead V5 or V6 identifed the LVOT VT as originating from a coronary cusp with 88% specifcity.
• In Cusp VTs the presence of an S wave on lead I and an R/S ratio>1 on lead V1 or V2 can be seen
• It was difficult to separate the right coronary cusp focus from RVOT VT due to there close proximity. However, right coronary cusp VT can be distinguished from RVOT VT based on the location of the transitional zone in the precordial leads. Precordial R wave transition occurred on either lead V1 or V2 in the patients with right coronary cusp VT, whereas precordial R wave transition occurred on either lead V3 or V4 in patients with RVOT VT.

Ablation

• Pacemapping often requires high output pacing (between 5 to 40 mA) and long pulse width (> 40ms)

Criteria for Successful Ablation

1. The earliest V at the successful ablation site must begin earlier than the earliest V recorded from the anterior interventricular vein and -35 to -60 ms prior to QRS
2. Perfectly matched pace mapping from a coronary cusp must be performed successfully.
3. The distance from the ablation catheter tip to both left and right coronary ostia should always be 1.0 cm.
4. Tip temperature should be maintained at 55°C during energy delivery.

References

1. How to Diagnose, Locate, and Ablate Coronary Cusp Ventricular Tachycardia HITOSHI HACHIYA, M.D., KAZUTAKA AONUMA, M.D., YASUTERU YAMAUCHI, M.D.,MASAYUKI IGAWA, M.D., AKIHIKO NOGAMI, M.D., and YOSHITO IESAKA, M.D. J Cardiovasc Electrophysiol, Vol. 13, pp. 551-556, June 2002
2. Ventricular Tachycardia from the Aortic Sinus of Valsalva. Natale A. JAAC 2001:37:1408-1414