Focus on the origin of NCT

1. 5TH ANNUAL SCIENTIFIC CAMBODIAN HEART ASSOCIATION CONGRESS
PREAH KOSSAMAK HOSPITAL
S. SAKHAN, MD
NOVEMBER 2018

3. § Definition of NCTs
§ Cases presentation
§ Discussion
§ Take Home Message

4. ➣ NCTs are defined by the presence in a 12-leads EKG :
- QRS complex duration less than 120 ms
- HR greater than 100 bpm
➣ The NCTs is a blanket term that includes a lot of different rhythms and is simply a starting point on
the road to diagnosis.

5. Fig1 : Schematic the origin of arrhythmia

7. Is it wise to say all NCTs are SVT ?

8. § A 61-year-old male
§ Suffered an acute STEMI, undergone RCA stenting with a DES.
§ Later on, he has RCA in-stent thrombosis requiring repeat stenting with a DES.
§ Develops sustained tachycardia + lightheadedness but no chest pain or dyspnoea.
Sundhu M, Yildiz M, Gul S, et al. Narrow Complex Ventricular Tachycardia. Cureus 1423

9. 115ms
115ms
Sundhu M, Yildiz M, Gul S, et al. Narrow Complex Ventricular Tachycardia. Cureus 1423

10. Sundhu M, Yildiz M, Gul S, et al. Narrow Complex Ventricular Tachycardia. Cureus 1423

11. § The arrhythmia failed to respond to (IV) Diltiazem
§ but resolved after 150 mg of (IV) Amiodarone !
§ EP study was performed using PES from both the RVA and RVOT.
§ A non-clinical rapid monomorphic tachycardia was induced.
§ Dissociating the HB and A from V activation, confirms VT in orgine.
§ The patient underwent subsequent placement of a dual-chamber ICD.
Sundhu M, Yildiz M, Gul S, et al. Narrow Complex Ventricular Tachycardia. Cureus 1423

12. § A 62-year-old male
§ Hx Inferior MI with CABG and a dual chamber ICD
§ Multiple shocks related to recurrent VT despite anti-arrhythmic drug therapy with Sotalol
§ Coronary angiography revealed a chronic total occlusion of the RCA, with moderate
atheroma in the LCA.
Stephen et al. Ischemic Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 14 (4): 203-210 (2014)

13. Stephen et al. Ischemic Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 14 (4): 203-210 (2014)

14. Stephen et al. Ischemic Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 14 (4): 203-210 (2014)

15. § EP study was performed
§ Baseline measurement including anterograde and retrograde testing respectively.
§ NCT easily induced by PES from RV with a QRS morphology which was very similar, but not identical,
to the QRS morphology during SR.
§ His-synchronous VPB did not advance the subsequent His signal.
§ It was not possible to entrain the tachycardia from the Atrium.
Stephen et al. Ischemic Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 14 (4): 203-210 (2014)

16. § Activation mapping localized the earliest
ventricular signal to the base of the LV
approximately 2 cm below the His catheter
within the border zone of a large area of
scar on the inferior LV wall.
§ A mid-diastolic signal was identified in this
area and pacing from this site was
associated with concealed entrainment.
Stephen et al. Ischemic Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 14 (4): 203-210 (2014)
Fig2 : 3D voltage mapping of LV. Bipolar voltage < 0.5mV designated as scar (gray)
and normal voltage as > 1.5mV (purple) with area of intermediate voltage
(yellow/green/blue)

17. § RFCA was delivered at this site with termination
of the tachycardia after 16s.
§ No Purkinje potential was recorded at this site
either during tachycardia or during SR.
§ The tachycardia was non-inducible with
programmed stimulation subsequently.
§ The patient made an uneventful recovery and
remains well 6 months later with no recurrence
of VT.
Stephen et al. Ischemic Ventricular Tachycardia Presenting as a Narrow Complex Tachycardia
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 14 (4): 203-210 (2014)
Fig3 : Fluoroscopy of catheter position at successful ablation site

18. Fig4 : Schematic of potential mechanisms of narrow QRS VT

19. § A high index of suspicion should be maintained that any tachycardias , NC or WC, which commences
only after MI may be Ventricular in origin.
§ In 1988 study by Tchou, et al. reports of middle-aged males with a history of MI and scarring who
presented with a NCT which was ventricular in origin.
§ In 1991 study by Hayes, et al. on VT reported a prevalence of 4.7% (five out of 106) with narrow QRS
complexes.
§ In 2006 study by Bogun, et al. confirmed the involvement of HPS in post-infarction ventricular
tachycardia which had narrow QRS complexes.

20. § MIs are frequently complicated by tachyarrhythmia, which commonly has wide QRS complexes.
§ However, a NC-VT is not unusual and the nearly indentical QRS morphology the SR might lead to an
erroneous diagnosis of SVT unless alert to the possibility of this rare form of VT.
§ EP studies may be useful to help eliminate uncertainties in tachycardia mechanisms in such
challenging cases.